#299 ‒ Optimizing muscle protein synthesis: the crucial impact of protein quality and quantity, and the key role of resistance training | Luc van Loon, Ph.D.

22 Apr 2024 · 2 h 30 min

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Podcast Summary: The Peter Attia Drive - Episode #299

Episode Overview In this episode of *The Peter Attia Drive*, Dr. Peter Attia interviews Luc van Loon, Ph.D., an expert in skeletal muscle metabolism, focusing on optimizing muscle protein synthesis through the quality and quantity of protein intake, and the role of resistance training. They delve into the significance of various protein sources, the impact of exercise on muscle health, and the nuances of protein digestion and absorption.

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Key Topics & Discussions

Introduction to Luc van Loon

  • Background in physiology and exercise, focusing on skeletal muscle metabolism.
  • Work includes research on substrate selection during exercise and protein metabolism.

Protein and Muscle Protein Synthesis

  • Key Factors: Insulin and triglycerides play vital roles in energy metabolism, particularly in endurance exercise.
  • Protein Quality: Different types of proteins affect muscle protein synthesis rates.
  • *Animal vs. Plant Proteins*: Differences in amino acid profiles, absorption rates, and overall effectiveness for muscle synthesis.
  • *Whey vs. Casein*: Whey protein is rapidly absorbed, while casein offers a slower release of amino acids.

Digestion and Absorption of Proteins

  • Digestion Process: Begins in the stomach and continues in the duodenum with enzyme action.
  • Impact of Food Texture: Ground beef digests faster than whole steak due to increased surface area for enzymes.
  • Protein Composition: The amino acid profile influences muscle protein synthesis; higher leucine content in whey compared to casein.

Timing and Distribution of Protein Intake

  • Optimal Protein Intake: Around 20 grams of protein per meal is suggested to maximize muscle protein synthesis.
  • Post-Exercise Feeding: Consuming protein after workouts enhances recovery and muscle synthesis. However, benefits can extend into subsequent meals.

Aging and Anabolic Resistance

  • Anabolic Resistance: Older individuals tend to have a reduced response to protein intake, which can be overcome by resistance training.
  • Muscle Health in Aging: Exercise can mitigate muscle loss and maintain muscle mass, even in older adults.

Importance of Resistance Training

  • Discussed the necessity of resistance training in maintaining and building muscle mass, especially in older populations and during periods of inactivity.
  • Clinical Findings: Studies show that resistance training can prevent muscle loss during androgen deprivation therapy in prostate cancer patients.

Collagen and Its Role

  • Collagen supplements are popular but provide limited benefits for muscle protein synthesis compared to high-quality protein sources.
  • Importance of glycine and proline from collagen, yet overall amino acid balance is crucial for muscle health.

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Key Takeaways

  • Protein Quality & Timing: Both the quality of protein (animal vs. plant) and the timing of intake significantly influence muscle protein synthesis.
  • Exercise Impact: Resistance training is crucial for maintaining muscle mass, particularly in aging populations and those undergoing medical treatments that may cause muscle loss.
  • Aging & Anabolic Resistance: The decline in muscle synthesis response with age can be mitigated by engaging in regular physical activity and adequate protein intake.

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Final Thoughts This episode emphasizes the critical intersection of nutrition and exercise for muscle health, especially in the context of aging and recovery. Luc van Loon's insights into the biochemistry of protein metabolism provide valuable guidance for optimizing muscle protein synthesis through diet and exercise.

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Additional Resources

  • To delve deeper into the topics discussed in this episode, you can view the [Show Notes](https://peterattiamd.com/lucvanloon/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=240422-pod-lucvanloon&utm_content=240422-pod-lucvanloon-podfeed).
  • For exclusive content and benefits, consider becoming a member of the podcast community [here](https://peterattiamd.com/subscribe/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=240422-pod-lucvanloon&utm_content=240422-pod-lucvanloon-podfeed).

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Transcript

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0:10Hey everyone, welcome to the Drive Podcast. I'm your host Peter Atia. This podcast, my website, and my weekly newsletter all focus on the goal of translating the science of longevity into something accessible for everyone. Our goal is to provide the best content in health and wellness, and we've established a great team of analysts to make this happen. It is extremely important to me to provide all of this content without relying on paid ads. To do this, our work is made entirely possible by our members, and in return, we offer exclusive member -only content and benefits above and beyond what is available for free.

0:46If you want to take your knowledge of this space to the next level, it's our goal to ensure members get back much more than the price of the subscription. If you want to learn more about the benefits of our premium membership, head over to peteratia -md .com forward slash subscribe. My guess this week is Professor Luke Van Loon. Luke is a professor of physiology and exercise and the head of the M3 research unit, which is a part of the Department of Human Biology at the Faculty of Health Medicine and Life Sciences at Masterich University. He is internationally renowned for his research that is focused on skeletal muscle metabolism, inhumans, and he is focused on four main fields of interest, which include skeletal muscle metabolism, exercise metabolism, sports and clinical nutrition, and aging.

1:37I first came across Luke when I saw a video from a lecture he gave many years ago, and it's not common that I'm watching a video of somebody talking about protein, where I'm actually stopping and watching it for great lengths because I'm actually learning something. So I immediately became hooked, became more and more familiar with his work, and ultimately wanted to have him on the podcast. Luke received his PhD from Masterich University in the Department of Human Biology, subsequently did an internship at the Department of Kinesiology and Health Education right here in Texas at the University of Austin, though long before I got here.

2:10And then he did a couple of postdoctoral fellowships, one in Australia and one back at Masterich University. He is also the associate editor of the International Journal of Sports and Exercise Metabolism and is on the editorial board of the European Journal of Sports Science. In this episode, we talk about the role of insulin and glucose for endurance exercising. We talk about the role of protein in all of this. We speak about how different types of proteins in different forms will foster muscle protein synthesis in different rates. So we talk specifically, of course, about the absorbability, digestability, amino acid quality, and other features there.

2:48Of course, we talk again, and length about some of the different types of protein, first of all, the difference between animal sources and plant sources, but using probably more helpful designations than that, we get into even specific types of proteins. So for example, even if you're talking about milk -based protein, what are the differences between way and case and we also talk about the use case, if at all, for collagen protein. Talk about how protein digestion is impacted not just by the type of food but even by the preparation of the food. And we cover the relationship between activity, lean mass, building muscle and protein from resistance training and the role that protein specifically plays in that in terms of timing and type of protein.

3:28So without further delay, please enjoy my conversation with Luke Venloon.

3:37Luke, thank you so much for being here. I know it's evening time for you. And as we were talking a moment ago, I think there's a decent chance we're not going to get through all of this. You laughed when you saw my agenda of topics. So maybe we will have a little Austin reunion. We'll do the next one in person here in Austin. But let's give folks a little bit of a bit of your background. You had quite a storied resume. Can you give us a little bit of the highlight? Yeah, as many people I didn't know were to go to college. as most of us exercise physiologists, we're all field athletes. So we want to know how our genetics can be actually just compensated for by science.

4:15And so I wanted to do movement sciences. So I studied movement sciences here, Masteryct, the Netherlands. After that, I went to Austin, Texas for my master internship to work with Jack Wilmore, who people in next -sized physiology will obviously know at UT. After that I finished my PhD in Maastricht again. Then after that I went to Melbourne to work with Mark Hargraves, also well known to most people in this field, spent some time in Melbourne and then came back and actually did the rest of my career here in the Netherlands. So from assistant prof to associate and to prof here and that's already been like 13, 14, 15 years ago.

4:53Today, we're going to not talk so much about the movement stuff, although that would be obviously very interesting in our audience. I think we'd appreciate that as much as what we're about to talk about. But we're going to talk more on the nutrition side of things. We're going to talk specifically and in great detail about protein. But that's, if I'm reading your CV correctly, not necessarily the first foray into nutrition that you took correct. No, that's correct. So my main interest was in the beginning and also my PhD was in fuel selection. So substrate selection during exercise. And of course, most of that stuff is done during endurance type exercise.

5:28And if you're thinking about substrates, you of course are not thinking about protein, which is from a quantitative point of view, is not a very good substrate. So it's carbohydrate fabbentabolism. And most important or most interesting thing for me at that time was that they had set up a stabilizer to research facility here. So you could track metabolites. the first things that that lab did is actually measuring carbohydrate oxidation rates. So you would simply throw in some stabilizer -to -labeled carbohydrates you drink, and by simply the oxidation of those carbohydrates, and you would actually expire, exhale 13 CO2.

6:07Because then if it's labeled with 13C, you get 13 CO2 after you oxidize it, and by simply acquiring your expired breath, you can actually calculate how much of your energy came from a sports drink. Now it was so cool for me at that time. Just to be clear, you would also need to know the amount of oxygen consumption to be sure that that CO2 came from glucose and not from fat, correct? Yes, so it's a combination of indirect calamity. So that's total oxygen uptake, total carbon dioxide production combined gives you total energy expenditure and also total oxidation of carbohydrates and fats. And then because you know what percentage of the carbohydrate derived CO2 was expired by 13 CO2, you could calculate back how much of the carbohydrate is coming from your drink.

6:56And that is cool because they see how much of the drink are you actually using. Now it's interesting, Luke, that there's a method obviously that uses deuterated water and C13 doubly labeled water to measure energy expenditure in a free living environment over a long period of time is the method you're referring to only using labeled carbon and therefore only suitable for a short period of time to evaluate glucose oxidation or do you also label oxygen and potentially get energy expenditure over a long period of time. If you use doubly labeled water, you can actually do that over several days. You need several days in order to do that.

7:33So this is really a way of you're getting carbohydrates in. You start oxidizing them that CO2 is also mixed in your blood. So it takes a while before the expiration of labelled carbon is also a good proxy for the amount of carbohydrates that you're oxidizing. So it takes about two hours. They are a nice steady state. That's why we're measuring endurance athletes, of course. And then for one or two hours, you can measure oxidation rates. So that's only for exercise trials, for example. And did this tend to be more accurate than the estimate you would get of carbohydrate oxidation rate just using the indirect calorie metri and the weird equation, or was the point here to determine not total carbohydrate metabolism, but specifically how much is coming from the drink.

8:20Exactly. Exactly. So the basis is still in the red calamatory. So respiratory exchange ratio and then from the carbohydrates, oxidation, you can see how much of that carbohydrate is coming from your drink. Got it versus glycogen, for example. Exactly. So you have your glycogen coming from your liver, you have your glycogen coming from your muscle, you can actually detect that with an intravenous glucose tracer with a different label, and then you have your 13C label in your drink, so you can actually see all three substrates. So you can see what is coming from the drink, what is coming from your muscle glycogen, and what is total coming from your plasma glucose, which includes, of course, the drink, but you can subtract that from total.

9:00And then you have all three different sources, and of course that was not enough for us. So we also wanted to know what fatty acids are being used from your intermuscular triglycerides, so the fat inside your muscle fibers, and what is coming actually from the fatty issue that is releasing fatty acids and then transported to the circulation and taken up in the muscle. Because that is also an important topic for ad leads, but as we will probably touch upon later, also for example, diabetes patients. Well, it's not going to be possible for me to just leave that one. alone, Luke, and jump into protein because I got to understand, especially for my own selfish needs as I'm preparing for kind of a long distance endurance thing.

9:42I thought my long endurance days were behind me, but I do have one more very long endurance event that's going to take about 20 hours coming up in a few months. And it's been so long since I've thought about how to prepare energetically for something like this. And I really believe at least based on my history that nutrition can make or break you in these 20 -hour marathon events. So tell me some of the things that you learned in studying, even though I know you're only studying it only, you know, over two hours. But what did you learn about, for example, the rate of carbohydrate metabolism, muscle glycogen, liver glycogen in the steady state?

10:23So I thought we already had a quadrilist, but I think just add something to it. Now, so one of the most important things is basically all the glucose that is extra coming in your circulation will be used for oxidation during exercise. So we continue supply of glucose coming from your gut is a good idea to save your liver glycogen, to keep your liver glycogen intact or at least not depleted too fast. And so if you can maximize that and of course we know that with glucose or glucose polymers, That is about the rate of 1 to 1 .1 grams per minute. So about 60 to 70 grams per hour. However, it can be a little bit higher if you actually add some fructose, because fructose requires a different transporter.

11:08So if you combine both glucose or glucose polymers with fructose, you actually can get a little bit higher, but that's only for really the high end athletes that can actually gain that high energy expenditure. then you can maybe go to 1 .31 .4 grams per minute. And so that would be the ideal from the carbohydrate point of things. But of course, if you're doing a 20 -hour endurance event and you're well trained, you'll actually be using quite a lot of fat because that's what you're training for. And in that case, you require your fat stores in your muscle as well as in your, yeah, I mean, you already have enough fat stores in your fat issue, of course, because theoretically, if you're 70 kilogram weighing lean men, you can run for almost, I think so.

11:54So it would be probably three days or something like that, 24 hours. Of course, that is only theoretical. But it's obvious that the amount of fat inside just clear muscle tissues is also very relevant because I mean, you know, you appreciate that your muscle glycogen storage increases as you become a better endurance athlete or better athlete on itself. Same goes for into musculoskeletes, right? Right. Just to clarify one thing, Luke, because people who listen to this podcast may remember, gosh, it was a couple of years ago, I had Gerald Schulman on from Yale, Jerry's one of the world's experts on insulin resistance.

12:31And we spoke there about the mechanism by which intracellular fat, or it was actually diacyl glyceride, not triacyl glyceride, within the cell was one of the hallmarks of insulin resistance. But I think you're talking about something different here. Are you talking about triglyceride between the muscle cells and not in? Now this is actually, I mean, you will actually appreciate that as a physician as well. So a lot of the clinical work is done by clinicians and people that focus on the clinical work. The exercise physiologist focused on the exercise work and sports and sports supplements. You do notice that a lot of work that has been done in the two fields does not get used by either side.

13:16So when I was doing substrate metabolism muscle and the selection and how that is organized and regulated, first I was interested of course in carbohydrates because during moderate to high intensity exercise, from a quantitative point of view that's the most important substrate source. And so as exercise intensity increases, you depend more on your endogenous carbohydrate source. But what you can see is doing moderate intense the exercise and lower, much of the fat is actually being used by athletes and that increases also during high -entense the exercises you become a better athlete. So as a good athlete you get the same exercise intensity, even the same relative exercise intensity, you can oxidize more fat and that is the benefit because you need less of your limited stores of carbohydrates.

14:02Now the body of an athlete or the muscle of an athlete adapts to store more glycogen, but But it also adapts to store more fat inside muscle fibers. And that's a it's from my cell a lipid. So that's really inside the cell, lipid droplets that you see in a muscle fiber. So in these days, I was actually cutting muscle biopsies up looking under the microscope. And if you actually see those individual fibers, a lot of lipid droplets, it looks like you're looking at a soup from the top and you see those little droplets floating around. Now, that is a storage that is ample used by athletes and Hans Hopler in those days was one of the first to do electron microscopy pictures of that.

14:43And if you then look inside one of those lipid droplets, you see that on most of those lipid droplets, there's a mitochondrion attached to it. It's like a backpack. It's like the mitochondria is where the backpack of a big lipid droplets. And so we started and I think we were running the first to start measuring how many of that lipid inside the muscle, inside the muscle fibers, is being used during exercise. And we did that using those stabilizer toasts indirectly, but also by taking muscle biopsies before and after exercise and looking at the number and the size of these small lipid droplets.

15:20And that goes down. So Adelites use a lot of the intromiocelar lipid for their energy provision. and particularly in the beginning of exercise. And then you think like, hey, this makes sense. When you start exercising, all your liposis in your fat tissue takes time to get that process going. Pufusion liposis. Yeah, this is almost immediate access, prime the pump. Exactly. Yeah. So just to be clear, I was never aware of this that you could actually see mitochondria on the fat droplets within the cell of the muscle. With this be a fundamental distinguishing feature between the muscle cell of an athlete and the muscle cell of somebody with type 2 diabetes, which will also have fat within the muscle.

16:06Will it simply not have the mitochondria and therefore not be turning to it as an energy source out of the gate? Very likely, I've never seen electro -microscopyctius of that because it's difficult to quantitative because there's so many lipid droplets so you can't make it quantitatively. But we actually, and exactly what you said, there were also other people in our university in our department looking at diabetics. And then I started to be interested in, hey, what's the difference? Because if you compare an endurance strain athlete and a diabetic, they both have huge intermiased cello lipids.

16:38And the difference is, the athlete uses it, the pleats it, builds it up again, but the diabetic doesn't. And if we actually exercise the diabetics, they are not really using that indoor mice cellar lipid. And that makes perfect sense because why? Because the blood is full with free fatty acids. So the muscle is not going to use those limited stores in the muscle because it's constantly getting free fatty acids from the circulation. So in the diabetics, it's a permanent storage with very little turnover while in the athletes, it's a substrate source that is constantly being used. And so the use the turnover of that substrates is the important factor driving towards insulin resistance or actually insulin sensitivity.

17:24Yeah, I remember reading a paper 12 years ago that very erroneously came to the conclusion that athletes on a ketogenic diet who had high amounts of intramiocelular lipids were insulin resistant. And I was shocked because I couldn't believe they could fail to look at turnover rate and actually differentiate a static from a dynamic process. This is obviously a more important example and a more relevant example. Yeah, one of the fun things that we actually did is we saw that ed leads in the beginning use a lot of intermyselolipids. But in the second stage of that and due and exercise, they stopped using them.

18:05And then we thought like strange, why is that? But it It actually happens when your free fatty acids in the circulation go up. And it makes a sense, of course, by the time that your etepost tissue is constantly actually feeding free fatty acids, you're not using that storage depot anymore in the muscle. So as soon as free fatty acids went up, the use of intermyocylolyphids went down. And then we thought like, hey, what would happen if we reduced the free fatty acids in diabetics during exercise? And we actually gave them a sip of mox. So, it's something that blocks adipose tissue like polices.

18:40So in the diabetics, the free fatty acids would not go up anymore. They would actually go down and they suddenly started using the intermiased cell lipids. And that improved post -exercise insulin sensitivity. So, it's a very nice way to stimulate, to turn over, of the intermiased cell lipids. And it's probably one of the mechanisms that makes insulin sensitivity improve after exercise. What role does insulin play in accessing the intramiosellular fat store? Obviously, insulin plays along with maybe hormone -sensitive light paste. The most important role in determining the rate of esterification versus lipolysis in the fat cell.

19:21Obviously, we know the role insulin plays for glucose into the muscle cell. Obviously, there is also non -insulin -dependent glucose uptake. But where does insulin, if at all, factor into both the athlete and the diabetic with respect to how fat is getting into and out of the muscle or into the muscle and then oxidized? So insulin, of course, also stimulates fatty acid uptake. But if we're talking in an exercise setting, insulin doesn't play a whole bond role anymore during and immediately after exercise. Because stimulation of your AMPK pathway also stimulates glucose uptake, as you know, the glut4 transporters are actually translocating to the outer membrane, insulin dependent or exercise dependence to separate pathways.

20:05For fatty acids, it's even a lot more difficult because the fee fatty acids and a lot of it is actually facilitated diffusion. Yeah, I was about to say because the membrane is fat soluble, I was going to ask you how I assumed it was just going to diffuse through with a gradient. A very chance -finding, we were just a lucky finding on the side of the study, when we were measuring depletion of intermiocel lipids in the leg in a non -invasive way using MRS magnetic resonance spectroscopy, we did that in the leg, but we just for fun, we also measured the arm. And of course, you're not cycling with your arm.

20:40So we did an MRI before and after exercise, and of course the fat in the muscle went down in the legs, but it actually increased in the arm. So simply the greater turnover, the greater flux of free fatty acids in inactive muscle, it actually increased the amount of intermised cellulipids. A lot of it is not regulated. The muscle is not dead intelligent. The muscle just takes what it can get. It's very opportunistic. Yeah, this is incredibly fascinating. What do we know about the endurance athlete's capacity to consume fat and during a steady state exercise? So, for example, if a person is doing, again, just be selfish and use my own example, right?

21:20If I'm doing a 20 -hour activity and let's just say energy needs are going to be relatively low because the energy expenditure is, let's just say we're requiring 500 KKH per hour. So we could almost meet that through ingested glucose. That would be 1 .25 grams per hour. But truthfully, that would be punishing on a GI system for 20 hours. So you'd want to potentially maybe limit that to 30 grams per hour of carbohydrate, which would meet about half those needs. Would you say, look, you're very likely going to need nothing else because the remainder of that will be met through endogenous fat stores and a little bit of endogenous glycogen, or would you say, no, you could prime that with a little bit of additional substrate that is presumably fatty acid.

22:11Yeah, I mean, that's a difficult question, of course, because nobody's done a lot of work in long term. I mean, that long term and during type activities. But after I've done, and this is always fun if you do nutrition research, first you start with carbohydrate related research, because I thought the B all and end all of everything is liver and muscle glycogen. But then you start looking at, oh, the intramuscular triglycerides are important substrate source as well. What happens if you deplete them after a few hours of exercise? And how far do you replete them? Because if you were to do a next session with depleted intermuscular triglycerides, you wouldn't have that prime that you're referring to.

22:49So repleting that is also important. And then we realize that only carbohydrates is not enough. You also need fat. And of course now that I'm actually doing a lot of research in protein, We now know that we also need protein and then we're back to food. But that's the little discussion. Let's talk about that. Let's talk about your transition. I could sit here and pick your brain all day on the carbon and fat issue, but how did your own interests transition you towards protein metabolism? So just going slightly back to your last question because I think you're asking also a practical question for yourself.

23:24So when we saw that fat was important in the muscle, we started also looking at post -exercise fat replacement. So you have enough fat to provide enough fatty assets during that long, the 20 -hour endurance event. But I think you should not start doing that with too low of an intermuscular fat level. And when we started talking with ultra endurance athletes, they were actually proving me right, but even though there's no data, they were saying like, look, I can't really perform in several day events, so multi -day events if I don't eat enough fat. And that's maybe because of the intermiased cell lipid storage that you want to replete between several days.

24:03And it takes one or two days to replete it. So if you do more of these 20 day events back to back, then the fed repliation is important. For single event, I would think it wouldn't be that important. Do you have a sense we do tend to quantify glycogen capacity. We would say maybe a healthy, athletic, reasonably sized male would have 100 grams of glycogen storage capacity in the liver, 3 to 350 grams in the muscle. I'm sure there are athletes even higher. Do you have a sense of what those numbers are like in the muscle for how many grams of fat could be stored in the muscle of a healthy athlete?

24:40No, it's way less than that. I think there were estimates and now I have to really think because I'm going back 20 years. I think it was also around like a hundred, 200 grams. But that's still a lot because of the color identity of that being higher. I mean, that's functionally as many calories as you would have from glycogen. Yes, but I think the calories are not important, the most important, but the priming those to actually cover from activating the adipose tissue towards having enough free fedia acid in this circulation. And that takes about half an hour, 45 minutes. And that's where it's important.

25:17Last question on this topic, I know I said we would leave it, but this just reminded me of something else, which is, what does the window of time look like in which an athlete has the greatest opportunity to replenish intramuscular fat stores and intramuscular glycogen? Presumably it's a window following exercise. How long does that window remain open? At first, I mean, they know no exactly, but within about the first four or five hours, we see that insulin that glucose uptake is less or almost not insulin dependent. So basically the more carbohydrates you ingest, the more it goes into the muscle.

25:56But then as your glycogen levels increase, then you get a break on glycogen deposition. So glygogen storage is inhibited simply by its content. So it's a self -limiting process, which is great because if you don't, you actually have a muscle disease. So the first few hours, all the glute -for -transporters are in the sacrolemma. So all the glute -goes that comes into circulation get sucked in the muscle. Meaning just the contraction of the muscle alone during exercise is getting that glute -for -transporter into the membrane without the need of insulin and it's open field running for glucose coming into the cell.

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26:36Exactly. And that's one of the reasons why exercise is so good for maintaining glucose homeostasis. It's not only the total amount of muscle, but especially the way you use the muscle. I mean, the easiest way to actually cruise to your organ glucose torments test is before you go to your GP, you actually run for two hours because then you'll have the lowest OTT day you'll ever see. Yeah, I did that actually once just as a test. I wanted to see how insulin sensitive I could make my muscles before a two hour OTT. And I don't remember the exact results, but it was astonishing. Glucose at the start is maybe 80 milligrams per desoliter, 30 minutes in an hour and two hours later, it never went above 100 milligrams per desk leader in glucose.

27:24But also, to your point about the insulin independence, I don't think my insulin went above 11. Even a fasting insulin above 11 is not uncommon. So yeah, that's a very interesting experiment. What about the fat window? Is that also about a four hour window? For those of you interested in that insulin effect, I mean, that goes up to 24 to even people have shown 48 hours often. And that is the reason why nowadays for exercise for diabetics. They say 150 minutes of exercise throughout the week. I would think that's a minimum. That's the advice. But at least every other day. And at least every other day is because every session improves your glucose homeostasis for up to 24 hours.

28:06So if that exercise is actually every other day, you maximize benefit from the exercise with each and every meal that you ingest afterwards. For fatty acids, it's actually less difficult because it doesn't seem to be tightly regulated because of the facilitated diffusion of your fatty acids. But of course, if you are an athlete and you're consuming a huge load of carbohydrates, especially also during exercise, of course, you're going to limit your lapolosis and then you have less fatty acids. So the only thing that we really did, that doesn't seem to be a short frame. It's just constantly going.

28:39It seemed like up to about 48 hours, the fatty acids, the into my cell lipid was almost at the same level again. And just to be clear, are you saying that most of the filling of the muscle with fat will come from endogenous fat stores via lipolises or is there a role for exogenous I .E. dietary fat in the post -exercise phase to boost that further? And I understand your point, but I want to make sure the listener understands that the relationship between carbohydrate and digestion and lipolysis is very clear. The more carbohydrate you ingest and the higher insulin goes, the more you inhibit lipolysis, which is the breakdown of fat from the stored fat cell.

29:23But with that explanation out of the way, does my question make sense for you about the source of the fat? Yes. So in well trained athlete, about 50 % of the fat oxidation during exercise comes from your intermuscular triglycerides. And the other 50 % comes from free fatty acids released from your adipose tissue transported to your blood taken up. Now, the only studies that we've done here was with fat supplements during exercise because there's not much reason to take fatty acids because there's enough fatty acid being released from your adipose tissue. We did play around, and I was Oscar Jokinder actually playing around, but if medium chain triglycerides, so medium chain triglycerides are actually smaller fatty acids, the tail is less long, and they can be actually transported directly into the mitochondria.

30:09So they don't need to connoisse CPT1 facility or transport. So we thought that was nice to get a faster oxidation labeled substrates. They show that the medium -chains rye glycerides, even during high -intensity exercise, are really oxidized and the idea was that could save carbohydrate use so that you can maximize fat use during high -intensity exercise and and therefore, spear glygogen and improved performance. Now, basically it worked with MCTs, but then we tried to see whether we could make it quantitatively interesting, and then almost everybody got the idea. Yeah, I was about to say the big challenge with getting sufficient enough MCT volume is the gastrointestinal distress.

30:56And I think for most people, at least if consuming it in a pure oil form, 30 CC is really pushing it. I mean, when I was hard on MCT oil back in the day, this is 12 years ago, I could do two tablespoons of MCT, so how many of our milliliters that is? That said, and I haven't done this, but I do see other products out there that are somehow waffleizing the MCT. They're almost putting it into a powder form. Have you seen any of these things? Yeah, I've seen suggestions that there's a lot of MCT's or MCT -like products that presumably have less issues on the gastrointestinal tract. Yeah, I haven't used them and I haven't used them in research.

31:41Still, I would contemplate like in what amounts do they actually contribute substantially so that it improves performance? And I think as long as you can actually reach your goals with carbohydrates, why would you play around? But yeah, is there a role for MCT oil? immediately following exercise as a very quick rapid source of fatty acid. Are the muscle ore you saying no because right after exercise, your insulin is so low, just let the lipolysis fill the tank. Why would you bother adding, we all want to lose a little bit of adipose tissue anyway, right? Yeah, I think so, my name is Neuroth, of course.

32:16So I love to see what is happening, but I don't think it has any relevance in practice. Okay. So with that very interesting detour out of the way, let's talk about how So your professional interests pivoted from this obviously interesting and relevant field to another. I think one of the interesting things was when I saw they called out the athletes paradox, I intermised a phety assets in high intermised cello -lippid stores in diabetic and obese people and also in athletes. So what is the difference between them? So I started doing some diabetes related research and exercise work in diabetics to improve insulin sensitivity and improve substrate metabolism.

32:55And then we were taking muscle biopsies. I meant to back then, Dr. Hans Geyser. He was actually teaching me how to take muscle biopsies. And he's a physician, so he was taking biopsies. And what we often saw is that when you took a biopsy from an athlete, it's like a chunk of muscle sitting there, like a piece of good steak. But then if we took biopsies from the diabetics, often sedentary people, it was like a blob. It wasn't standing up. It didn't have any structure. it was just like liquid. And then we always saw that and we were discussing that and it was obvious that diabetes or a more sedentary lifestyle comes with changes in muscle quality.

33:37And of course, if you start thinking about muscle quality, you start thinking about protein synthesis and protein metabolism. And because I was working with older people, because the diabetics were older than my athletes, this is much more interesting than the athletes. What is happening with that muscle? And then you automatically go from only substrate to protein metabolism and yeah, that's where I got stuck and still haven't figured everything out or actually I have more questions than I ever had before. Well, I think that's the mark of a really fun place to be truthfully. Let's give folks some basic background.

34:11Let's not say anymore about carbs and fats for the moment because we could spend hours just defining them. But I do think people at a high level clearly understand that if you include ethanol, there are four major macronutrients. But let's talk about this one called protein. What is protein? What are the building blocks? What's it's made up of? What defines a protein? Which ones can we make? Which ones can we not? I'll let you run with that in any way you see fit. Protein is one of the three macronutrients. Protein consists of amino acids. amino acids are the building blocks of protein. And so they're also the building blocks of ourselves because all our tissues is mainly protein, of course.

34:51We have, say, about 20 or depends how you define it, 2022, amino acids of which nine are essential. The rest is non -essential. The definition of essential is always confusing to my students because essential means we can't make ourselves so there's no endogenous synthesis in our bodies in humans, whereas the non -essential you can actually to some extent synthesize. Now I'm probably mucking it up for everybody because what I always say to the students that doesn't mean that your non -essential amino acids are not essentially your diet and then they never differentiate between them anymore because as far as I know I reckon that it's almost impossible to synthesize those non -essentials.

35:36That is something that is still a topic that I would like to dress, but that's difficult in humans, of course, because you can't simply just throw away all the protein and start feeding amino acids. And maybe we'll just also, just so people kind of get a sense of these things. They're called amino acids because they have a very clear structure, and I have to be honest with you. My biochemistry is so rusty, but I sort of remember them having, was it, did they have a carboxyl head and a nitrous tail with a carbon in between and then each... Or organic acid. Yeah. Yeah. So it's an organic acid with this nitrous tail.

36:10So nitrogen is the big piece here that we don't see in carbohydrates and fat. Carbohydrates and fat are basically carbon hydrogen oxygen. Here you have carbon hydrogen oxygen, but you also have this big piece of nitrogen. So I'm sure we will talk about nitrogen balance. And then you have other things thrown in there. Methionine has a little sulfur in it and things like that as well. But I guess the point is biochemically they all have a similar backbone, but what differentiates the 20 or 22 of them is kind of the what's in the middle. That's the special sauce for each one. And that's what differentiates them.

36:42That's what differentiates them. Yeah, that also defines their individual characteristics. Now, we see that amino acids are important as our own building blocks, of course. And so that's why we need to consume protein because they provide us with those building blocks. But what is interesting and we'll come to that later is that those amino acids are more than building blocks. There are also sickly molecules that directly stimulate muscle protein synthesis. So they directly activate the empty pathway driving muscle protein synthesis. And so it's interesting and I always explain it to first year students, you have a building site where you actually have bricks being delivered and the bricks themselves pick up the phone and call the brick layers to come over.

37:28So it's really amazing how that works. So simply eating and I'll come to that later stimulate your muscle protein synthesis. Now, of course, I'm a muscle physiologist, so most of my work is a muscle. We've been starting to work also on different organs because it's of interest and there's not a lot of data there available. But what we do need to know is that you're synthesizing about 300 grams of protein on a daily basis. That includes tissues, that includes hormones, that includes enzymes, blood proteins, everything together. It's about average estimate by 300 grams. As most of the listeners will consider, is that they are consuming about say 70 to 100 grams of protein per day.

38:11That means that for 70 grams for one gram a day for a 70 kilogram of eight men, that will be your recycling 230 grams. And this is something that people don't realize. So yes, we consume food, And we need those building blocks, but you're also constantly using amino acids that are being released from the breakdown of tissues. And then you use them again. You're making 300 grams. You're only ingesting 70 grams. So that means on a 24 -hour basis, you're recycling 230 grams of amino acids from your own body. So you're very sustainable. Let's talk a little bit about the use case for it, right? So 300 grams being utilized per day.

38:55Let's talk about how that differs in an active person, a person who's strength training, a person who's doing steady state cardio training, a person who's not training. Let's just use those three examples. I don't think anybody would have died on that because this is on a whole body level. So organs still use the guts, everything. And I think if we're asking these questions, we have to just move back to a muscle centric perspective. There's a question I want to ask before all of this, which is a technical question that explains to people the methods that you use to actually do these types of measurements.

39:30You already talked a little bit about one isotope method with respect to carbohydrate metabolism. Can you explain the technical tools that permit this type of study for amino acids? on keep it very simple you have stable isotopes so everybody knows from high school or most of you will know from high school then in chemistry you have carbon 12 or carbon is weight of 12 in nature there's also carbon 13 and carbon 13 means it has an extra nutrient in its core it's stable doesn't fall apart you also have 14 carbon that's unstable falls apart and you're at radio activity and that's why it's a radioactive isotope now you can actually purchase carbon -13 labeled metabolites.

40:12And so you can also, by carbon -13C, carbon -13 labeled vanilla lenein, for example. Nowadays we often use vanilla lenein as the tracer because it's an essential amino acid that is hardly metabolized in muscle or not metabolized in muscle and it's not as volatile as, for example, lucine and lucine, of course, has a lot of other effects. So you want to have a nice stable amino acid that is a good representation of other essential amino acids. So if you actually buy 13c labeled finile underneath, you can dilute it in a bag of saline, infuse it in the body, and then you actually have like 5 % of all your finile underneath floating around your circulation, and then you take a muscle biopsy, then you take the muscle out of the biopsy, you take the protein out of the biopsy, you can even separate and mitochondrial protein or myofibular protein.

41:06So that's ectonymizing, for example. And then hydrolyze that protein back to its free amino acids, and I use mass spectrometry to look at how many of those amino acids in the muscle protein are coming from the carbon 13 -C labeled finiline. Now, a few hours later, you take a new biopsy, and you see how much more of that 13 -C finiline is built to do the muscle protein. If you divide that by the availability in the circulation and the time between the two biopsies, you have a fractional synthetic rate, jelly expressed in percent per hour. Now, on a daily basis, that's about 1 to 2 % per day. So, it's always confusing, it's always magic to me.

41:47That means if all the proteins in your muscle are generic, which they aren't, of course, but assume an average, then they are actually completely refurbished in 50 to 100 days. So, I always ask people to look at their own arm and realized that in 50 to 100 days they have a new arm. It's completely refurred. That is amazing. So, the individual proteins in the muscle are broken down and build up again. And we can measure that by infusing those labeled amino acids and simply measuring their synthesis rates. First of all, that is an absolutely amazing idea that is, of course, self -evident based on the nature of what we know about protein turnover, but when phrased that way is simply remarkable.

42:36Right? We don't take it as so earth shattering that every three months our entire hematopoetic system turns over. I mean, we know this. We know that every 90 days a red blood cell is gone and it's replaced with a new one. Effectively, the entire red blood cell architecture in my body today is completely new from what it was three months ago. But when you talk about it through the lens of muscle, it's much more complicated. I mean, it's just much more difficult to wrap your mind around. Obviously, one of the questions is, but I don't notice any difference. What preserves the architecture? This gets to what is being replaced and what is technically not being replaced.

43:19How does the shape change so that we don't look different so that we're not a constantly morphing creature. So you have more questions than I can ever answer, but that is also, and we'll come back to that later, I hope. So we started also measuring turn off rate of tissues other than muscle. And then it gets even more freaky. And then you start really thinking like, how is this regulated? Let's not do this because it will be confusing, but we've also measured protein turn -over in the brain, in the human brain. And then if you see those turn off rates, then you have different questions. but let's not go there, let's take it for the muscle for now.

43:54So it means that in order to keep the muscle and maintain muscle mass, you need to stimulate it because the breakdown will continue and so in order to maintain your muscle as it is, you actually have anabolic stimuli that stimulate the synthesis. And then we come back to nutrition and exercise because it's food intake and particularly, of course protein intake and exercise that stimulate muscle protein synthesis. How these two stimuli know which proteins to build and in what structure? Oh man, that is just an enigma. I always show a picture of Lance Armstrong and I don't know who I'm showing as bodybuilder, actually that changes every so many years, one of the Mr.

44:38Universe's. And so I showed him that these two guys have huge protein synthesis after an exercise session, But the phenotypic response is completely different. And so if resistance type exercise, you built a lot of my phyball protein. Well, the endurance athlete will build a lot of mitochondrial proteins. So how the body knows by the recruitment of your fibers, which proteins should be synthesized? I mean, we know a lot of molecular pathways, of course, but how it's directly regulated. I mean, first we thought we had everything by measuring mRNAs. Then we thought we had everything, my measuring Western Blots, protein content and protein phosphorylation.

45:16And then we went to trans -retomics and then we suddenly knew that we had post -translational modification and then we had M &A splicing. It's getting complex, the complex, the complex, the complex. Let's use that example, right? So we put up a world class endurance athlete against a world class bodybuilder. And let's even simplify the equation and take drugs out of it. So let's even suggest, let's talk about not the best body builder because obviously they are using high amounts of anabolic steroids But a world -class natural body builder who's still by any metric is enormous and a world -class endurance athlete The question of course is how does the body know in the case of the body builder to build myofibular protein Meaning to disproportionately build that whereas in the endurance athlete you're disproportionately building mitochondrial protein Now the obvious answer to me seems to be the training stimulus.

46:10The bodybuilder is pushing enormous amounts of weight repeatedly within the confines of certain reps and certain sets. And the endurance athlete is never, ever stressing the muscle at a single rep. If you think about it, an endurance like this might be 80 to 180 to 100 cadence. And they'll do that. They'll do hundreds of thousands of those repetitions, but none of them are as hard as the reps that the body builder is doing for six to 12 reps. So that's an obvious difference. Is the question that we don't understand how that is translating a signal into the MPS? Yes, I mean, we don't know. And if I would actually post this question to a second or third -year student, they would actually just move away from the real answer by going towards saying like, hey, it's different fibers.

47:00And of course, that's part of the answer because resistance type lead will more likely recruit the type 2 fibers. The more type 2 fibers are more likely to build in mass. If we see people doing resistance training, it's mainly the type 2 fibers that get bigger. We see that with the bodybuilders as well. You stack 2 fibers. The opposite happens when we get older. You get smaller type 2 fibers, actually. And that is where most of the muscle loss with aging actually comes from. Well, the endurance at least we don't see much happening with the size of the fibers. we just see greater capillary density, we see more mitochondria, high -density mitochondria, subcircle amelm mitochondria.

47:37So the adaptive response is completely different and part of it is because of which fibers you recruit. But it's not to complete answer because if you do for example you probably notice the discussion about high reps, low reps, low weight, high weight. There's now very very nice studies that show if you do high reps with low weight, if you do the two exhaustion, you also start using the Type II fibers and then you also get hypertherfee and that's a nice way especially in rehabilitation that you can actually drive those Type II fibers without putting too much effort on the just operated, the hip order, the leg, whatever just operated on.

48:16So it's not the complete answer. There's more going, but what is exactly the signal, the molecular signal from the the tension on the muscle towards the synthesis of the specific sets of proteins. There's enormous amounts of pathways involved, and I'm not sure whether we'll ever completely know what is happening now and where that selection is going to be. And that's actually... It's just so fascinating that we can't understand the cascade that goes from stimulus to muscle protein synthesis. Would it be reasonable to assume that the bodybuilder has more up -regulation of M -Tore than the endurance athlete, or is that even a stretch in terms of an assumption?

48:58Given that it's difficult to measure that. I mean, we now also know that a lot of the hypertrophy is actually M -Tore. The stimulation muscle -produced synthesis can be M -Tore independent. There's so many parallel pathways that are driving responses. And like I said, for example, if you ingest protein, you stimulate M -Tore signal. you stimulate M -on -A translation initiation and you get greater protein synthesis. But it actually is not continuously stimulated if you do not provide all the building blocks. So if we, for example, after exercise or even at rest, we provide people with the brine chain amino acids.

49:34So main and lucine is driving that antibiotic response. It's the signaling response. Here you stimulate muscle protein synthesis and for up to two hours. But if we give the same amount of Lucine on this case branch chain amino acids in the similar amount of milk protein. So containing the same amount of branch chain amino acids plus all the other amino acids, we see that response is actually sustained over more prolonged period of time. So it's not only the stimulation, it's the stimulation in combination with the right amount of building blocks at the right amount of time. How I always tell it to the students, you have a parking lot where you want to park as many cars as possible, you can put the light on green to drive in, but if there's no cars, nothing's going to happen.

50:15And so it's a combination of the right, secretly responses, plus the availability of your substrate. I want to come back to this in detail because it's very relevant. It's also there was a recent study that came out that I believe you were an author on if I'm not mistaken. Maybe I am mistaken, but the study looked at the duration of muscle protein synthesis following the digestion of different types of amino acids. So we come to that. But let's take a step back for a moment and make sure we at least cover the basics of how protein is even digested. And I want to talk about three types. So one, I want to talk about a whole meal.

50:50So a meal of protein that often comes with fat. So let's talk about eating a steak. And they want to ask how that differs from two different types of milk -based proteins, way protein and casian. So, I want to understand what is actually happening from a digestive standpoint and how the thing that you actually consume and put in your mouth turns into building blocks that presumably are being absorbed somewhere in the Ilium or Jajunum. So, I'll just first take protein and then go to the specific protein sources or meals. So protein is basically ingested, goes to your stomach, acid is added to it.

51:34So you have the first basically start of the digestion. You actually can get clotting of your protein due to the acid. We'll come to that later away if we compare casin versus weight. Then it goes to the duodenum, then you have all your enzymes being unloaded on your protein if they can get access to it. You actually get the free amino acids. A lot of people have suggestions that also oligopeptides die and tripeptides, so small proteins composed of a few amino acids. There are transporters in the gut that would allow them to actually enter the intestinal wall or the intestinal cells. We think from a quantitative point of view, it's hardly relevant, but it's possible.

52:15The amino acids are then, part of them are actually incorporated into intestinal protein, because the gut also has a very rapid protein much faster than muscle. So part of it actually remains in the intestinal tissues as protein. Some of it is released on the other side of the intestine in the portal vein. The portal vein transports it to the liver. The liver can do something with the amino acids if it wants to make proteins. But most of it is actually released in the circulation. And there it can basically perform that to all those different tissues, taken up and used for muscle protein synthesis.

52:50We don't have a real storage depot. There's a small free amino acid pool if you compare it with the intact protein pool. They always say it's very small in muscle, but acutely after a meal, it can actually vary a lot. So it's a buffer, a temporary buffer, but we don't really have real storage sites for amino acids. So that's the whole pathway. Let's finish one thing there, actually, Luke, because that's an important point you rays, which is unlike fat, which can be stored in unlimited quantities and glucose, which can initially be stored in glycogen, although that's a relatively finite store, and then eventually can be stored as fat through denova -like peogenesis.

53:32What exactly happens to excess protein if we consume it? Let's just use an extreme example, right? Like, I sit you down and give you a 200 gram protein meal, make it whatever number you want such that the point is you clearly have excess amino acids once fully digested. What do you do? What does your body do with those? Yeah, so first, the amino acids, you said that we have no storage like the glucose, the stored is glycogen, the fatty acids are stored as fat, but the amino acids are stored as protein. But is it a real storage depot? Now if you ask me and yourself, we hope we're not losing muscle, so we say we don't have a storage depot.

54:11But if we end up in a concentration camp, then we're actually quite happy that we have a storage depot of amino acids in the form of muscle. So it is a storage depot, but hope that we're not using it. So if we get excess protein, we thought, I mean, in the literature, a lot say that everything that you can't immediately process is being oxidized. Now that study by your entomaler that you just referred to that we published a few weeks ago, we showed that about a hundred gram oxidation, at least in the first 12 hours after ingested is very overestimated. But I mean over the long run, if you keep continuing eating more protein in a setting of overcalories, you simply store the protein as fat.

54:53What's the pathway that that happens? Because it's so funny. When I think back to biochemistry classes more than 25 years ago, what I vaguely remember was amino acids could undergo gluconeogenesis to become glucose and then either glycogen or fat. Is that what you're referring to? Yes. Okay. And then it's different for different amino acids. And of course, it's a very inefficient way so that it's also one of the reasons why people tend to get less fat accumulation if they overeat in a form of protein besides the satiety effect. Right, because there's a thermogenic and thermodynamic loss or use of energy just in the metabolism of protein that itself is obviously beneficial if your goal is to store less energy.

55:42Correct. Now, I have to say something about the techniques that we use because we were interested, I mean, we've done protein synthesis measurements all the time, but at some point, exactly where you were saying, I wanted to know more about the digestion and the absorption prior to stimulating muscle protein synthesis. And in order to understand that, you need those stabilized up traces, not only in an infuse rate, but you would like to have those labeled amino acids in the food as protein. Now, you can't purchase those. So about 15 to 20 years ago, we worked with ethorea in France because they already made intrinsically labeled protein.

56:23So what they did, they infused a cow with those labeled amino acids. And so the cow integrates those labeled amino acids in the milk. And then you can actually use the milk in clinical experiments. Now we wanted to take it one step further because we wanted to have the number of labeled amino acids in the milk, so high, which is very expensive, to actually see the digestion and absorption, but even the incorporation in the muscle. So we spent more than 50 ,000 years of tracer and the first time that's pretty challenging because you actually put it in account, you infuse it in account and you just hope you are ever going to see that money back.

57:02We put labeled vanilla nine in account. The cow made milk, we extracted the milk, we got the protein powder and we used it in clean up experiments to assess digestion, absorption, release, extraction over the like an incorporation in the muscle. Now, if you see this, I mean, we can now go into the quantitative measure because we actually did this to see the difference between KZN and Wei, welcome to that later. But simply that I bought traces, isotopes in the US, they send it over, I had it in a small jar on my desk, then I went to bargaining it to, or firstly, France actually, and we've done it a few times since.

57:45You actually, if you use it in a cow, you actually get the milk. You bring the milk to a factory to extract the milk protein about a year later. That same infinal anine is now integrated in milk protein on my desk. The same whole molecule that came from the US to my desk, from the US to France in a cow, then from the cow's milk on my desk again. Then it went into an older subject in the study. We took a muscle biopsy. Now, year later, I have a muscle biopsy on my desk that has that same full amino acid integrated in the muscle and I actually dissolve it, bring it to the mass spec analysis and I have that same amino acid in my hand again.

58:32That amino acid has been around for four years and went from a lab in the US through a cow, through cow's blood protein, through the milk protein, to my desk, back into somebody else's leg. That's amazing. And just give me a sense of yield when you made the caseeaner the way protein from the cow's milk, what fraction of the phenylalanine was actually labeled with the isotope? We got 25 % of the tray so we found back in the milk. And so you can imagine as a Dutch person I'm supposed to be cheap. So losing 75 % of that money in a cow is not something that you can sleep on. So we butcher the cow.

59:19How much of the phenylalanine did you find in the meat of the cow then? Exactly. So this was really funny because we actually butcher the cow. So we got, of course, it gets difficult because you have to multiply it by a total amount of meat. And if you butcher a cow, you don't get all the meat. But we sampled all the organs. And that was a starting point for us to start measuring turnover of other organs and humans. But what was interesting is that different muscles had different enrichment, but it was all ballparked the same. We never calculated whether we actually came back to 75 % but it must be very close.

59:51But we use that meat and that would come back to your other question to see whether there's a difference in the digestion and absorption when you ingest meat as a steak. Or if that same steak was first put in a meat grinder and you had basically mincemeat. Huge difference. With mincemeat you get more rapid digestion and absorption which should also expedite your muscle protein synthesis because the more rapid absorption the greater and faster the release of losing the greater distillation of muscle protein synthesis. Now that was a fun study for us to do and when we were writing it down I was trying to find in the literature some suggestion that the mincemeat first instinct there was some data to suggest that it improves accelerates digestion and absorption potentially improves metabolic responses.

1:00:39We came up over study that was done in the 60s that showed that this was epidemiology and has its limitations, that people that have their older people that still have their own teeth generally also have their muscle still intact. So that was a nice link to say that your mom has been right on a lot of things because I mean I spent and probably like 30 million euros of research money in the last 30 years to provide clinical proof that my mom was right and a lot of things. Meaning when she said, chew your food. Chew your food, but even something as simple as sitting up right. Huge effect on digestion and absorption.

1:01:15So all of these things come back. So chewing is a factor that drives the antibiotic response to feeding. And so it's really funny than if you go to mixed meals, but you just said, if there's micronutrients coming together, a lot of energy will actually reduce gas gig empty or slow down gas gig empty. That is one factor, but the matrix of foods, the chewing of the foods, all of these, whether you cook it or not, even that is an important one. We'll come to that later as well. I mean, there's so many topics here. We did a study with eating eggs that were raw or cooked. A huge effect on digestion and absorption.

1:01:52I actually tried to have a silvestre alone on that paper, but he never responded, unfortunately. Rocky. Rocky's protein shakes. We basically said was Rocky right or wrong because when the first movie we actually used part of his script. He's ingesting those raw eggs. Wouldn't it not be better to actually cook those eggs because you have more rapid digestion and absorption? I think of how many raw eggs I consumed as a child because I watched Rocky. It's insane. How I didn't get Salmonella, it's a miracle. Anyway, so it was. Let's go back to the example of the steak versus the ground beef. So iso quantities, so 50 grams of protein in a steak that obviously will have some fat with it.

1:02:38In fact, let's make them not just iso -chaloric and iso -protein, but everything about them is the same. So same amount of fat, same amount of whatever. One is ground, one is not. Talk me through the kinetics of those two in an individual. Yeah, so I think the most important factor is of course that all the enzymes that are being released in the duodenum and also part of it also the gastric emptying of course is accelerated with your minstMeep, with your ground beef. So you have more rapid gastric emptying. The acid has already had more space to actually have its effect, faster gastric emptying than it gets into the duodenum.

1:03:12You don't have those big chunks of meat, but you actually have those enzymes that can actually attach everywhere much easier. So you get more rapid digestion and absorption. It's a little bit similar to for example, casing away Everybody knows now everywhere. I mean all the athletes that say are we need way protein But that's because my cell a casing the other 80 % in milk 20 % way 80 % Casing that was actually the first study that's actually the study why we did the intrinsic label protein We got the milk process the milk down to my cell or casing and down to way because for all those years, especially the companies was telling me that pre -digested protein, the hydrolyzed protein, is more rapidly digested and absorbed.

1:03:56And I said, where's the proof? And they said, like, yes, this in vitro essay shows, I said, in vitro essay doesn't mean anything to me. In vitro essay, if you have all these tubes and glass things and then they screen for digestion and absorption. But to me, the human and vivo system is much more complex because all those tubes and glass cylinders are actually alive in the human. So I want to assess this in a human and vivo setting and then they asked me like, how would you want to do it? And then I said like, yeah, I would infuse a cow and then this and that and then they looked at me like I was completely crazy.

1:04:29Took me seven years until they funded it. And then we got the milk processed my cell acazine And we also got the mycelic casein and we pre -digested it with enzymes. So you get a casein hydrolyze. Now we've all checked them for digestion and absorption. And then you see that the hydrolyzed casein and also the way protein are much more rapidly digested and absorbed than the mycelic casein because the mycelic casein in the acidity of the gut starts coagulating, like spoiled milk or something like that. And so the gastric emptying is probably reduced or slowed down, but also the capacity of the enzymes to basically start digesting the foods.

1:05:16And so that's how we now know that rapidly digestible protein is more likely to stimulate muscle protein synthesis to a greater extent. So there's two characteristics of a protein that is the digestion of it and the rate of digestion. But then you would expect that the pre -digested casin would do exactly the same as a wayprotein, but it doesn't. Just as rapidly digested and absorbed, but the wayprotein still has a greater antibiotic response. And of course, that might have something to do with the amino acid composition. And we know the wayprotein has a higher leucine content. And so if we add, for example, free leucine to casin, we get a greater antibiotic response.

1:05:58So obviously the amount of Lucy is important factor. So in a nutshell, two characteristics of a protein and their capacity to stimulate muscle protein synthesis is digestibility, the rate of digestion and the amino acid composition with particularly the amount of Lucy in the protein. And anything that slows down the gastric emptying or the release of Lucy in the circulation will likely also slow down the antibiotic response. So let's unpack that a bit because there's a lot there. We're kind of collapsing digestibility and rate of digestion into one feature. Although, can't they be disentangled a little bit?

1:06:38Because the example of the whole meat versus the mince meat, presumably they have similar digestibility. They have just as much sinew. They have just as much fat. But one has been effectively broken down and it would have a higher rate of digestibility. correct? No, I think with cook meat, the digestibility is the same. It will take a little bit longer for the steak than for the mincee. Sorry, I mean the rate of digestion wouldn't that be quicker? Yes, yes, yes, yes, exactly. I mean, if you ever enforce a medical, you want to do a few years of research and master's rate, please come over because these are all the same questions that I had and there's so many more.

1:07:18I mean, we as nutrition scientists, we love to work with a single ingredient because otherwise we don't know what is going on. So most of the work that we've done in the past is actually comparing protein x with protein y and then with protein, I mean protein isolate or protein concentrate. So protein powers and that's why a lot of people in the public media just of course read or like to see our studies because it's about the powders they eat but of course normal people don't eat protein powers. Protein isolates are concentrates. We eat foods. Now if you go back to the literature and looking at how many studies have assessed the antibiotic response to eating foods, that is very slim.

1:08:01Because I mean nobody is interested in foods. I mean it's often like is protein x versus this because if you start having meals, everything comes together. Plan -based proteins, animal -based proteins, the processing of the protein whether it's heated or not heated, whether it's cut fine, minced, not minced, chewing well, not whether it's combined, how much on the plate, how many fibers, all of these things together, actually determine the antibiotic response to feeding, and then the digestibility becomes most important. I think 99 % of our studies, the digestibility is not an issue because we use extracted proteins.

1:08:41Also, when we go to plant -based proteins, and that's, I guess, also a topic that you want to discuss, most of the plant -based proteins that we have assessed are plant -based proteins, and I prefer to call them plant -derived proteins that have been extracted from the whole foods. And then the digestibility, it's often still little less than animal -derived proteins, but it's not a major issue anymore. It's a major issue if it comes in the form of whole foods. All right, let's go through this in some detail because this is super fascinating, but before we I do, I want to really ask the question of how much does it clinically matter the rate at which muscle protein synthesis is stimuli?

1:09:24Because what I'm hearing so far, and I want to try to summarize this for both myself and the listener, is that you really have three factors that are going to determine the rate at which muscle protein synthesis takes place. You have the digestibility of the thing that you are ingesting. And this could be the difference between a plant derived protein and an animal derived protein. This could be the difference between a cooked protein versus a not cooked protein. And this could be the difference between two different types of proteins, period. You then have the rate at which this protein is digested.

1:10:04You can picture a curve with the X -axis being time and the Y -axis being digestion. The rate of digestion will speak to the shape of that curve. And again, I think there are probably many things that impact that, but the obvious examples you've given here would be how the food is cut and it could be ground beef versus whole beef, how well the person choose, all of those things impact the rate. And then the third factor is the composition of the amino acids itself. You've alluded to leucine many times. We talk a lot about leucine on this podcast because of course it is the number one in the most potent mTOR stimulator.

1:10:45But obviously there are other proteins as well, lysine, methionine. These are probably more pro -anabolic and therefore the concentration of distribution of amino acids plays a role. Now, let's go back to the macro question, which is a person is looking to maximize, optimize, maintain, increase lean body mass. This should be a goal of everybody, right? It doesn't matter if you're a 75 year old woman or a 25 year old man, the maintenance of lean body mass, if not the increase in lean body mass is a very important pillar of living a long healthy life. So if that is true, then presumably anything we can do nutritionally, we'll talk about training later, but anything we can do nutritionally to maximize or increase muscle protein synthesis should be good.

1:11:39But the one thing that we're missing is the window over which that happens. So is the goal always to maximize that for the highest peak independent dependent of the base, or do we want more of a time -release defect, where we say, look, we'll take a lower rate or a lower peak muscle protein synthesis, but I'd like to sustain that for many, many hours. You're laughing, so I've touched a nerve, which means I'm probably asking a question you are asking, but I'll let you go from there. This is awesome. I mean, these are all the questions that the field has and that we all have. So it becomes much more difficult because one factor we didn't discuss is the amount of protein because the amount of protein also has an effect of course on the curve and you can compensate with the amount.

1:12:28We'll probably come back to that as well but yeah, as estimations up to two the three grams of loose seen in a meal. We'll actually induce a rapid increase in circulating loose seen and that will stimulate muscle protein synthesis and if you have enough building blocks available you have an antibiotic response for at least up to five hours. So this has led most of us in the field to believe that it's best to ingest at least now we're talking about healthy people. If you become older you become less resistant to the antibiotic properties of amino acids and antibiotic persistence probably also something that we come back to later.

1:13:03But if you're a healthy, active male or female, 20 grams of protein is assumed to be the optimal amount to maximize muscle protein synthesis for up to four to five hours after a meal. And this is the reason why in so many packages you now see 20 grams, every way you see 20 grams. Now that comes from studies showing that ingestion of 40 grams of protein does not result in greater muscle protein synthesis rates than 20 grams of protein. So it's assumed that 20 gram is the optimal amount in healthy people and of course we always have those discussions. If you're 120 kilograms you probably need more.

1:13:41If you're 50 kilograms you probably need less. Yes, but you can't do a study with every individual in the world. But 20 grams. Now, if you assume that you will have an antibiotic response to each main meal, then the advice is there to ingest 20 grams of protein with each main meal. Now, if you're becoming older, there's suggestions you need more to compensate for that, but let's stick now with healthy people. That's 2020, possibly also an evening protein snack, and then you already have 80 grams of protein, which for most people is already more than one to 1 .1 grams per day. Now, we are people that believe that you actually could use more protein, which automatically happens when you become active, because when you become active, you eat more, and then you easily eat more than 1 .1.

1:14:28So it's a non -discussion. But so, the idea is, distribution of protein that every meal is an antibiotic response. Just one question before you go further. other, this 20 grams is the maximum amount of protein you need to get maximum protein synthesis, muscle protein synthesis, was based on what type of protein? That was based on milk and egg. So there was a study on milk and there was a study on an egg. Okay, so it's whole food. It's not using just way or just casein. No, it's not whole foods. This is protein constraints. So egg protein constraints, I'm not protein constraints. So that's in a very important point because as I said, if your digestibility is not 100 % which in a meal is never, of course, and you have a delay in digestion and absorption, then 20 grams could be suggested to be a minimum.

1:15:20Yeah. So in other words, what I'm hearing here is for people like me who don't really like shakes that much. I prefer to eat food as opposed to drink shakes. I do drink them because because sometimes it's convenient. But if you're going to try to get this through food, by definition, you're going to be working with an inferior protein from the standpoint of speed in terms of digestibility and rate of digestion. So you might need a protein meal that's 30 grams or more than if you're 90 kilos, you're probably on the bigger end of that. Anyway, you might be 40 grams that you need per meal of real food.

1:15:54Is that kind of how you would think about that? Yes. Yes. And so, automatically also get to that because we always have those discussions, of course, because if I say that you need more protein, you're in just more protein, and they look at me like I'm advocating a high protein diet, but these discussions are, of course, always a little bit weird. If you have a 65 kilogram weighing two at a France cyclist, and he only consumes a very little amount of protein in the form of only 10 % of his energy intake, he's still ingesting probably more than two and a half grams of protein per kilogram body mass per day.

1:16:24Even though he absolutely doesn't need it for his limited amount of muscle. The more active you become and the more healthy you are, the more protein you consume. We always have, I mean, World Health Organization says, .8 grams per kilogram body mass per day. But yes, maybe you can survive on that. That's fine. But it's certainly, in my beliefs, not optimal. But whether it's optimal or not, it's a non -discussion. Every healthy, relatively sedentary person, I mean whether it's here in England or the US, healthy people, nothing strange and not complete recreational athletes, already consume between 1 .1 and 1 .3 grams of protein per kilo and more than that.

1:17:02And they're not even trying to consume more protein. We're typically pushing our patients much higher than that. We're asking patients to be closer to 1 .6 grams per kilo per day. And truthfully, if we're really trying to put muscle on people and their training volume is high, we're closer to two grams per kilo. It's great if you can reach that. I mean here in the hospital, I mean we're doing a lot because I do a lot of clinical work So we evaluate it protein intake in the elective hip and knee surgery patients So the all the population, but these are not sick. They're coming in for a new knee or new hip So this is a new generation of patients that we get of course because in the past I was associated with a lot of pain But these are patients that want to go skiing with the grandchildren again So they want a new hip or new knee.

1:17:51So they come in. They're very healthy, but in the four days that they're in the hospital To go back to your advice aspen guidelines for example between 1 .2 and 1 .5 grams of protein pekinia and body mass per day That's the clinical advice for recovering patients You know what they actually so in our hospital? So what they actually get what they're being delivered is It's point eight grams. How much lean master they lose in four days of in activity? Welcome back to that. So they get point eight and you would say like oh give them more. They consume point five. So the healthy patients in the hospital here, the healthy patients go for elective surgery in those four days.

1:18:32They consume point five grams, which is one third of the clinical guidelines for the advice amount. And they lose about one point four kilograms. Wow. So they'll lose more than three pounds of lean mass in four days. And I've talked about this extensively on the podcast about the asymmetry in how quickly you lose versus how long it takes to get back. And of course, we talked about this a lot in the context of falls that result in fractures because here it's an even more vulnerable population for many reasons. first, unlike the elective hip replacement and the elective knee replacement, whose patients are generally very healthy and able to get back to PT quite quickly, especially in the hips.

1:19:15The people who are falling and fracturing femur and neck, neck of femur and hip, they're typically not as healthy, and they're much longer to get back to recovery, and they're potentially bedridden for much longer periods of time, and oftentimes they never make it back to the level of muscle mass strength and function prior to, in fact, I'm not sure if you're aware of this statistic. You probably are, but Adam Cohen on this podcast mentioned that, you know, we talk a lot about the 15 to 30 % of people over 65 who will die within a year of a hip fracture. Well we don't talk a lot about of the people who don't die call it the 70 to 85 % who don't die within a year.

1:19:5450 % of them never regain their same function pre -fall. And many ways I find that statistic even more profound. I was giving lectures for a group of older people, general public here, and I basically mentioned those numbers, not thinking about basically what I was saying. So half the audience turned white when I said that because of course there were a lot of people that actually broke their hip. But we took biopsies from patients coming in with a hip fracture after falling. And we compared that muscle with aged matched people that didn't have a head fracture, didn't have a fall. And we compared it with young women, most women are the ones with a head fracture because the men have already passed away.

1:20:35But you actually saw the size of the Type II Fibers was tremendously smaller in the women with the head fracture than the ones that didn't have the head fracture, even though we match for almost everything, lifestyle and everything. What's very interesting there is the causality could be in reverse. I think you could also make a very compelling case that having smaller type 2 fibers, which means having less power, having less force generating capacity, would make you more susceptible to a fall. In fact, I wouldn't be surprised if there's a bidirectional association. So lower type 2 muscle fiber size and density, much more predisposition to a fall.

1:21:17Once you are inactive, you now experience even greater atrophy, which as you pointed out earlier, atrophy of the type to a muscle fiber is, I would argue it should be described as one of the hallmarks of aging, right up there with decreased mitochondrial functioning, increased senescent cells. All of the things we typically think of with aging, we should really be adding atrophy of type 2 fibers. And that's why maintaining muscle, there is more than maintaining muscle. It's also so many, especially maintaining the type 2 fiber size. Because what we now often see with patients getting back and especially now with COVID, we are sending people home much more fast because we don't want them to get a bacteria or anything like that.

1:21:57And we don't want them to attract COVID. So we send them home earlier. Now what happens when a lot of all the people go home, even if it's not a hip fracture, but an elective knee or hip surgery, everybody means well, so children, grandchildren, will act the first thing that they will do while you're in the hospital, they'll put your bed downstairs into the living room. So those people will never walk stairs again. First of all, they're afraid of walking stairs. They won't walk stairs again anymore because everything is put down. So they never recruit that type two fibers anymore. They might go for walks, but you don't recruit those type two fibers.

1:22:31So you need to stand up from the toilet several times in a row. You need to do or if possible resistance training. You need to have somebody do resistant straining with your walking stairs. You need to recruit those type two fibers because otherwise it just goes down. I mean we now believe that age -related muscle loss, I mean it's a demographic but it's not a physiological process of a slow decline in muscle. We now believe it's short, successive periods of reduced physical activity that are actually experienced after which they don't fully regain their muscle. And that adds up in the last two decades of life.

1:23:10And that seems to be contributing to the muscle loss that we see in those demographics. Let's talk about that again, because I think that is such an important point that I want to make sure not a single person listening to us missed that point. Let me restate it and I want you to clarify. We have long looked at data. These are all sorts of data. These are anthropometric data. These are functional data where we put activity monitors on people. And there is an unambiguous and clear decline in spontaneous activity, deliberate activity, and lean mass in the aging individual. and the decline starts somewhat slowly and by about the seventh decade starts to accelerate.

1:24:05By the eighth decade, when a person is in their 70s, the decline is so rapid that it appears almost irreversible. We would typically talk about this as an inevitability of aging. Hey, that's just the physiology of what happens to the muscle. But I'm going to go, you said something entirely different, which suggests that it is not inevitable, and that it is not a continuous slope of decline that reflects some physiologic process within the atrophying muscle, but instead it's a series of discrete declines each one precipitated by a period of inactivity. Some of them perhaps deliberate, meaning, hey, I'm going on vacation for a week and I'm just going to sit on the beach and do nothing, some of them forced upon us by injury or illness.

1:24:59First of all, did I get it right? Is that what you basically said? Yes. And I think everybody has that observation. Think of parents or grandparents that you saw in the last, say, 10 years before they died. Everybody will say, it started with that urethra infection. It started with that surgery on the hip. And then you actually have all these little episodes and they you saw that happening. And that's exactly what is happening. But it is, of course, muscle centric. So I'm talking about muscle loss. Of course, if we're talking about cardiovascular disease and progression, that's a different story.

1:25:33But for the muscle loss is not something we don't believe anymore that it's in an individual, there's not a gradual loss over time. Because in the individual level can be completely different. The demographic showed is because as we age, there are more people in that situation where they have short successive periods of reduced physical activity. And I think one of the first period people to actually publish this was Douglas Penn Jones who unfortunately passed away himself at a way to young age, but he called it the catabolic crisis model. What I find interesting about that is you mentioned that maybe this doesn't apply to a decline in cardio -respoutory fitness or cardiovascular functionalism of the things.

1:26:16Maybe, but I would argue that a muscle -centric view could potentially be the most important view, because when your movement stops, everything else deteriorates with it. People say, well, what would that have to do with heart, health, or brain health? I would argue it has everything to do with heart, health, or brain health. When a person becomes sedentary, everything deteriorates in its wake. Of course, your cardiovascular system will deteriorate at an accelerated rate. And of course, we know unequivocally your brain will erode at an accelerated rate when you become inactive. And of course, we know that the quality of your life, your happiness, your wellbeing will deteriorate as you become inactive.

1:27:02And so you could make a very compelling case, I believe, that a muscle -centric view might be the most important view. I agree and that sometimes it's like talking to a mirror. As you know, when you respond, we've done bad rest studies in healthy people because we often use healthy young people as a model to see what inactivity does. And besides that 1 .4 kilograms of muscle that we see disappear in a week or if we immobilize a leg almost 220 grams of muscle that is lost in a week, we also see a massive decline in oxidative capacity. We see a decline in insulin sensitivity. So all of these markers that we have for cardiovascular, mother -batic health go down in a single week of inactivity.

1:27:47So it's completely right. But of course in one person it might be the cardiovascular decline that is driving the muscle loss. While in the other person it's the muscle loss that's driving the cardiovascular decline. Yeah. I'll make another shameless plug for an idea that we talk about a lot on this podcast, which is this idea of the centenary into Catholic, and this idea that the best way to avoid this fate when you're middle -aged, when you're young, whenever, is to be very deliberate and specific about the type of training, and of course nutrition, that is necessary to have the most physically robust final decade of life, what we call the marginal decade.

1:28:24And so if you train with great specificity to be very active and very independent, and free of pain and all of those things in the last decade of your life. By definition, you're going to be doing a lot of varied forms of exercise and you're going to have to be supporting that nutritionally to get there. I want to go back to kind of one last housekeeping issue on the protein side, which was the difference between whey and casean protein in identical amounts relative to the parameters you've spoken about digestibility, speed of digestion, and amino acid composition. What are the differences and where do you see the use cases clinically between them?

1:29:10So the digestibility is the same. It's 100%. So there's no differences there. But if you ingest casene versus, and that's my cellar casene versus way protein, the way protein is much more rapidly digested and absorbed, you see a greater spike in your essential amino acid concentrations in your blood, including lucine, and you get a greater stimulation of muscle protein synthesis as a result. However, the longer you measure, the more the casing catches up in the way. That's also something that you have to realize. Yeah, tell us about that study that just came out a few weeks ago, which seemed to challenge a lot of the conventional thinking around the amount of usable substrate that one could ingest.

1:29:54So traditional thinking had been boy, it's awfully hard to use more than 40 to 50 grams of protein in a meal for muscle protein synthesis. And if I recall, you had three groups in this study, a group that was given zero protein, 25 grams of protein and 100 grams of protein. That was all case in, correct? That was milk protein. Constructed. It was a milk concentrate. So that means equal parts KCNN way or what was the breakdown? 80 -20. 80 -20 in favor of which? KCN is always 80 and way is 20 in milk. Okay. So if you have milk about 80 % is KCN 20 % this way. Got it. And then tell us what you saw in that study over a long enough period of time.

1:30:38So this was a study where we use that intrinsic labeled protein combined with introvunus infusions of amino acids and that allows us not only to measure muscle protein synthesis, But also, how much protein is actually released in the circulation from what you ingest, and so we could make a full quantitative assessment of what is happening. Now previously, like I said, most of our studies people like to work on office hours, so you have two hours of a run -in period, maybe an hour of an intervention, and then four to six hours of post -prandial, so after a meal measuring of muscle protein synthesis, those are long days.

1:31:16So most of the studies so far show that 20 grams of protein does not do better than 40 grams of protein to stimulate protein synthesis for up to four to six hours because that's typically what we do. Why do we always measure a four to six hours that's all the labs doing this kind of work is because that's the time between two meals. So that makes sense. So the 40 grams always, if you see the studies and a lot of other labs, it looks like a greater response than the 20 grams, but it's not significantly different. And what we saw with the intrinsic label protein, that a lot of the protein is not digested yet or at least not released in the circulation.

1:31:53And the longer you measure, the more of the protein is still coming in. Same with what I said, the case in is catching up on the way because a lot of the case in is not absorbed yet. So what you're in wanted to do and this was crazy because he wanted to ingest a hundred grams of protein to be honest He's so crazy. He actually wanted to have more treatments and it said it's not gonna happen because that's way Expensive and this was already very expensive So it is zero to only five is what is being advised to give a take and then the hundred gram as an absolutely Unpractical amount and so we actually measured if I'm corrected for eight and twelve hours after the ingestion.

1:32:30And so what you saw is that if you measure for an extended period of time, that 100 gram is still increasing muscle protein synthesis for a longer period of time, resulting in a greater response over time. So the suggestion that you can't get a greater response with more protein is biased. It's biased because you don't measure long enough. Now the problem is, This is a study that everybody at least in my field needed to see. So the better understand what is happening, but it doesn't necessarily translate. And of course, that's the problem now. If papers people start calling me, like interview this, interview that, like, should I eat one meal a day?

1:33:09No, that's not what we're saying. I still think that it's good to have a distribution of protein throughout the day that every meal has an antibiotic response. But it doesn't mean if you have small meals that you're going to disappear in three weeks. So the body adapts and if the body has a huge meal, it's still being used. It makes sense because if you have a, we also wrote it in a discussion. If you have a snake or crocodile that runs in so many days, devirus, the goat or chicken or whatever, then it can actually see that animal actually stuck in the gut for weeks and it's actually consuming it.

1:33:44Now, to some extent humans can also do that. So it just shows you that the response, there's no limitation in the response and it can actually range longer than what is previously expected. Do you think if you did that experiment, but instead of using a milk concentrate, which was majority casian, you used a pure way isolate? Do you believe that you would have still seen muscle protein synthesis at the 12 hour mark or do you think that the rapid digestibility of way would have changed the kinetics significantly and you would have been largely done at the four to six hour mark? I think the difference between the 25 and the hundred grams might have been smaller but it would still be evident because then the duration of the extension is small of course with the way then with my cell acacy but the comparison with milk is very small because I mean milk still is very rapid I mean, it's always funny that people say like this is slower, this is fast.

1:34:45It's all relative. Yeah. It's all very fast. It's all concentrated proteins. If you compare it with full meals, you get a completely different picture. And that's what Philipp Pinkert's in our group did. He compared the real meal. A vegan meal versus a typical Dutch, you know, not even know what I was still allowed to say that typical meal was actually in Holland vegetables, potatoes and a piece of meat. Now, we made those two plates having exactly the same energy and exactly the same amount of protein. But now, we also have that digestibility factor in there because we weren't using powders in a drink.

1:35:22We actually have a full meal, a plate with all vegan, all foods, and a plate with a piece of meat and potatoes and some veggies. And was the vegan plate cooked protein or was it raw? Yes, it was cooked protein. but it has a little bit more fiber to play this also a little bit bigger because the energy densities of course smaller and then everything comes together also with the digestibility. And then you actually saw no measurable antibiotic response with the vegan meal and you saw a massive antibiotic response, muscle protein synthetic response with the omnivorous meal. And that shows you that, I mean, and that doesn't mean before everybody just staggles again that I say that you shouldn't be even vegan.

1:36:07But the point is that a non -neivorous meal with animal derived proteins has a greater response when you compare it in a amount, the same amount, matter the same amount of protein. So quality counts. Yeah. Let's go back to what you talked about with respect to. We completely talk about the relative speed between way and casean. But let's put those in the context of a meal. So what does the kinetics curve for a casean shake look like compared to ground beef or whole steak? Is it significantly faster? No, that's similar. Cook beef is still very fast. So if you have cooked meat or concentrated protein isolate from an animal source, it's all very rapidly digested and absorbed with speak amino acid levels, I think between 30 and say 75 minutes.

1:36:57If you have a full meal with potatoes, veggies, fibers in it, it will take two to three hours longer. From a very selfish standpoint, I want to ask you a question. So I always do my strength training in the morning. Many days, I just don't, even if they're not that hungry or I kind to run out of time before I need to jump into stuff and I'm not always diligent about eating or consuming protein right after that workout. Now truthfully, in part, it's because, well, I want to ask you this question. Let's just assume two scenarios. Scenario one is finish exercising, finish strength training, consume nothing but water, coffee for another three or four hours before consuming a high protein meal, versus finish exercising and immediately consume 25 grams of way protein in a shake, with nothing else in it.

1:37:49Just way protein in water, you're getting 100 calories, chug it down, and then eat that protein -rich meal of 40 grams four hours later. Significant difference in muscle protein synthesis between these two over the course of days, or does it all come out in the wash where assuming you get ISO amounts of protein throughout the day, does it matter? On 24 hours, definitely, there's a difference. For example, if you ingest protein immediately after exercise, you get at least for the first five hours, you definitely have a much greater response because exercise makes the muscle more sensitive to the antibiotic response to food intake.

1:38:28However, what people forget is that your response to breakfast in the next day is still increased. And probably also your lunch and dinner the next day. So if you do an exercise session today and you get all freaked out that you didn't get a milkshake after your session Don't worry because the next day all your three meals are going to be greater responses because of the exercise So I get so many times the question like how important is the meal before or after the exercise And I say if you do an consistent training then there's always three meals before your session and after your session, because you train every day, so then every meal is still responding to the previous exercise session.

1:39:11Now is there a benefit of immediately after exercise versus a few hours later? We've done that study, so not sure whether we touched the topic as well, priestly protein feeding, that's the topic that we've been working on, other one or so on patients. So we gave people, I think it was even 60 grams, really proofed principle study, exercise in the evening and then 40 or 60, I don't remember, we gave protein then and then we measured the response the next morning after breakfast, after 20 grams of protein in the morning. So what I was thinking like if there is a window of opportunity, then if you give 60 grams of protein immediately after exercise, maybe you shorten the window of opportunity.

1:39:52So if you already provided the exercise after the session, you don't respond as well to the next dinner the next morning. What I'm basically hearing you say is if you have 100 units of response in you, the timing of your meal might not impact the total amount of response. It just determines when that response occurs. If I slug that 25 grams of way protein as I'm walking out of the gym, I will get more of my 100 units of response then, but I will get less of it four or five hours later when I have a big protein lunch. I think that's a much clearer explanation then. So that was basically the design of the study.

1:40:31And it fits with what I've learned of course for glygogen because you ingest carbohydrates immediately after exercise, so you expedite, accelerate glygogen recynthesis. But if you don't have to exercise until two days later, it doesn't make a difference because then you have a full 100 % recovery of your glygogen. Which again is very different from the way I grew up. I mean, when I grew up as an endurance athlete, could all be wives' tails. But the traditional thinking was, you need to be mainlining carbohydrates the second you get off the bike or out of the water or whatever, because you have this very small glycogen window where for an hour you're going to maximally assimilate.

1:41:11And it might be the case that, well, it's true, your maximum assimilation would occur in that window, but you will still incorporate carbohydrates into glycogen later. it just might not occur at his higher rate. Is that kind of the same situation? If you're exercising every Saturday, it doesn't make a difference. Luis Burke has clearly shown within 24 hours, you're gliding back to normal. If you are in the Tour de France and you have to excel every day, you're going to miss the third day of the tour if you don't start taking in carbohydrates off the session. Now, going back to so that study, protein ingestion, after an exercise session before the evening, does that impact your response to the morning?

1:41:50And so the other trial was no protein after the exercise and doing the same thing in the morning. I thought that the response to breakfast will be reduced if you already ingested the 60 grams of protein in the evening. It didn't. The responses were exactly the same to my surprise. So the responses to breakfast exactly the same. So, net, I must say, that the people in just the 60 grams prior to sleep had a benefit in that time frame. Whether it's caught up later on 24, 48, 72 hours, I don't know. In other words, yeah, I was going to ask you that. You only did this for one dinner breakfast and sleep session.

1:42:29Yeah, so these studies, so the studies with infusion of traces are almost always limited to about 12 to 24 hours. Why? Because you have these turnover of the tissues. So at some point your tracer will become available from the breakdown and then you're measuring tracer recycling. It's different techniques and we can go into that with D2O. There's different techniques to counter that but if there's acute tracer infusion studies you're limited to 12 to up to 24 hours. But so far long -term training studies basically have shown that protein supplementation can further increase gains in muscle mass and muscle strength, that evidence is there, the evidence becomes smaller when people eat more protein.

1:43:12And it gets stronger if you look at people that do not consume enough protein. I mean, we had a black and white response to frail elderly, six months of training, if we didn't provide an additional protein, they didn't gain more muscle. So the more frail people are, the more important the amount of protein gets, but it's also because they're not consuming a lot. I want to actually come back to the elderly in some detail, but I do want to put a bow on this topic here, which is We don't really know over the long term meaning over months and years if there is a benefit to consuming a very highly digestible rapidly absorbed good quality amino acid composition protein in the immediate aftermath following exercise.

1:43:59It sounds like it's still unclear if there could be a net benefit. So if a person listening to this says, look, I want everything in my favor to maximize my odds of optimization and maximization of muscle mass, I'm going to consume 25 grams of way protein following every workout. Again, from a caloric perspective, it's irrelevant. It's 100 calories, right? It's like less than 5 % of your daily intake, but it would arguably be the most efficient way to deliver amino acids. Is there any reason not to do that. Let's just start with that. Is there any downside of doing that as opposed to going through the hassle of consuming a meal when you finish your training?

1:44:41No, the individual absolutely not. The only problem that I do have is that if you advocate too much to use protein supplements and stuff like that, people stop thinking about their foods. So we've had people coming in here saying like, oh, I put a lot of interest in my nutrition and my diets and then I asked them, so how do you do it? Yeah, I take 29 supplements. Just first think about your nutrition and if every meal contains good, solid foods and with ample, ample protein, if you're then on top of that, decide that it's easier and more practical to take away protein supplements after training sessions, be my guest.

1:45:17But if all the rest is crap, then please do not even consider those away protein supplements because first think about nutrition. So I had a lot of people in my life asking me like, how important is it whether I take my protein shake before or after the training session? But I had never somebody that came up to me like, look how important is it if I skip one training session? Or I miss one training session. Consistent training is the benefit. Consistent training so that every meal is a greater impact on your muscle protein synthesis. It's the same the question I always get like interviews on the radio and you say, Luke, what should we eat in order to lose weight?

1:45:58And I have only one to respond, it's less. Yeah, exactly. But that's people. It's easier to drink away protein supplement than actually just leave the house at six o 'clock in the morning and do an extra session of training. Yeah. Let's talk a little bit about eating less because again, people who listen to this podcast are very familiar with the I think about this, but I'll just sort of explain it to you very, very quickly. I sort of break it down into three strategies to go about eating less. So strategy one is a very deliberate strategy called caloric restriction. So it's the only way that you directly go about eating less, which is clearly what bodybuilders do where they're tracking every macronutrient, every calorie, they are counting them and they are shrinking that volume of calories lower and lower and lower to reach an energy imbalance that is sufficient for the amount of fat loss that they're trying to produce.

1:46:52Again, you could argue that this is the most flexible way to go about weight loss because it is agnostic to when you eat or what the actual constitutive elements are of the diet. It's really just paying attention to the energy balance or imbalance. The second way that you can go about doing this is indirectly through dietary restriction. You talked about a vegan diet. Hey, you're taking a lot of things out of the diet and many of them are energy dense. So there's very good chance you're going to lose weight just on the basis of the restriction. Similarly with a ketogenic diet or something of that nature, you're going to really generally eat a lot less and it's that effect of the diet on perhaps your appetite and food choices that's going to result in lower energy intake and therefore energy imbalance.

1:47:38The third technique also indirect is time restriction, which people call intermittent fasting, here you're going to make a larger and larger window of non -eating, and by extension a smaller and smaller window of eating, that eventually results in a caloric deficit. Now, we have historically, meaning in our practice, cautioned people about excessive use of time restriction if people fit a certain demographic. And that is you are obviously overnourished, which is our way of describing you have excess adiposity, you have high visceral fat, all of these things, you're metabolically unhealthy. So you're overnourished.

1:48:19We need to make you less nourished. But if you're also undermuscled, I get very worried about excessive time restriction, because with calorie restriction comes protein restriction and with protein restriction comes not just a reduction in mass, which on some level is the goal, but a disproportionate loss of lean mass. So I want to pause there. Does this resonate with you? All of these trade -offs? Foodie, agree in that. The third one is of course the time -restricted feeding or intermittent fasting. It works for people, but it doesn't work in a scientific setting because now there's a lot of studies coming out.

1:48:57We've also done a study on that. So if you standardize the nutrition, so the caloric content of the diet, you actually see exactly the same fat loss or weight loss with the intermittent or the time restricted feeding versus the same feeding, but then x % of less caloric intake doesn't make any difference. But let's just make sure people understand what you just said. And I want to make sure I understand what you just said. You're saying that if you normalize for calories across the course of the day versus in a shrunk window. If it's the same number of calories, there's no weight loss. Exactly.

1:49:32There's less weight loss. So if you have 25 % energy restriction independent of the timeframe, you're going to lose the same amount of fat mass. Now, for me, intermittent feeding or time -stricted feeding works. Because I go to the university, spend most of my day here, have no time to eat, running back and forth, and then I come home. I sit behind a computer doing all my emails and revisions of manuscripts and I start eating way too much and also crap food So I think more than 70 % of my food intake energy intake is between 7 or 8 and 12 o 'clock at night If I do time restricted feeding from say 10 to 6 I will lose weight Because I wouldn't have time to eat that amount of calories in that time frame and that's good for a lot of people because they actually change their homeostasis.

1:50:22For a few weeks, they lose a lot of fat mass, and then they start eating differently, and then they gain weight again. So sometimes it's easy to change your routine and your bad nutritional habits, but the time of feeding is not a metabolic effect to lose more weight. Yeah, so what we like to do to try to get around the effect of people losing too much lean mass, And again, I find this to be particularly important in women who want to lose weight using a time restricted feeding approach, but who frankly already have an ALMI or an FFMI that's in the bottom 20 % just for folks listening. These are two different ways that we measure and quantify lean mass on people.

1:51:08So this is people that are coming in with their undermuscle as we describe them. We will say, look, if you want to eat between 2 p .m. and 7 p .m. That's your feeding window. You have a five -hour window to eat. So 19 hours of not eating, five hours of eating, we find that women can't, and again, I say this because it is mostly women that experience this, but I think it could be true for anybody. It's very difficult to consume your total amount of protein if we're trying to get you to 1 .6 or 1 .8 grams per kilogram in a five -hour period. Furthermore, you have that 19 -hour window where you're missing one of the major inputs to muscle protein synthesis.

1:51:50So a workaround is, hey, during that period of time, you're gonna have two shakes that are virtually no calories but are gonna give you 50 grams of protein, a 25 -gram -way protein shake, again, just mixed with water at eight o 'clock in the morning, and again at 11 o 'clock in the morning, and then at two o 'clock you're going to eat a meal, and at seven o 'clock you're going to eat a meal. So you're going to get your total amount of protein, and yeah, you've sort of cheated on your time -restricted feeding because you've had 200 calories outside of it. But let's be honest, the purpose of this is caloric restriction.

1:52:25That 200 is relatively small compared to what you would have consumed throughout the day. So, again, long question I apologize. It's as much for the listener as it is for you. would you take that approach as a better way to tackle two simultaneous goals? Lose fat mass, preserve or gain lean mass simultaneously. That would be the main goal, and I would completely agree, but I miss one factor. I'm 100 % assured that you actually added the effect of the remaining... Of course, the training effect, yes. The resistance training. So even if you have, I mean, old studies show that if you have a caloric restriction, you lose fat free mass, you lose muscle mass.

1:53:04But if you do twice a week, a resistance training session, even in a caloric deficit, you don't lose muscle mass. So you can prevent the muscle mass with simply two sessions of resistance type exercise a week, preferably more, but of course that's the minimal. So besides that protein, it's the exercise that makes you respond way more to the same or less amount of protein that you ingest. And in the scenario I described where you're going to have that person have a protein shake at eight o 'clock in the morning and 11 o 'clock in the morning and then eat two meals between say two and seven It's probably not that important where the training session goes within that day at this point I mean, I think for many people it's just convenient to do exercise in the morning And I agree of course that that's half the battle is you have to have the training stimulus to produce the effect I mean, that's what people always ask us like, should we ingest the protein immediately after an hour after excite?

1:54:01Doesn't make a difference. Not really, because every meal following your training session will have a greater response. And so also, before the next session, there will again, three meals or four meals. So it's a continuous, consistent effect of training to make your response better to the same amount of protein. And also in the hospital, this is essential. So, simply feeding people more protein because the deficient and losing muscle is not the only solution. Actually if you make them a little bit more active between meals, every meal has more effect. If we do a little bit of exercise, more of the meal will actually be converted to muscle.

1:54:41So using that intrinsic level protein, I always have three different settings in my lectures. the first one is, this intrinsically protein shows you beyond any discussion you are what you eat. In fact, you are what you just ate. Now, funny enough, if you eat that same protein after you've done a little exercise, more of that protein is converted to muscle. So, if you're physically active, you are more of what you just ate. Now, every athlete is using this and every coach knows this, But we hardly use it in medical care. And so it gets worse because then you come to the third part of the lecture where I show you that with physical inactivity you become anabolic resistance.

1:55:25So if you become physically less active, you are less of what you just ate. Now the problem is when you become sick or ill or you get surgery, you have two issues. you exercise less or you become less physically active, but you also eat less. So it's a double bemid onwards. And that's what makes us so susceptible and vulnerable to a short period of inactivity or sickness. The term anabolic resistance is intuitive because obviously people understand what insulin resistance is. But with insulin resistance, we can actually really explain mechanistically what's happening. I referred to Jerry Schoelman.

1:56:03He provided a very, very elegant explanation of what's happening intracellularly. What the triglyceride or diosoglyceride, if I'm not mistaken, is doing in the cell and how it's impeding the signal transduction to move the glute -for -transporter up to the translocated site to bring more glucose in, etc. I haven't followed that discussion, but I mean, it's still a discussion which fatty acid intermediate is actually causing the whole signaling, is it the storage of the fed? Is the inflammation that you get from the storage of fed? Is it diacyl glycerol? Is it arduceramides? The fed? The acyl CoA?

1:56:40I mean, yes, but it's at least the inability to process that fed in the muscle is inducing the insulin resistance. So the question now is, do we have the same level of detail around what is actually inducing anabolic resistance? Which is a topic that I don't think people are as familiar with, but unfortunately need to be as familiar with given its prevalence under two conditions in activity and agent. I think that's the million dollar question. I think the first time that antibiotic resistance was published as a name was coined was by the people in the D. The late micro -enny. So he did the study where he provided essential amino acids to people young and elderly.

1:57:23And when they provided that a greater amount of essential amino acids you saw in the young people, a greater muscle protein synthetic response, as we discussed before, he got the greatest response, the highest muscle protein synthesis, following the provision of 10 grams of essential amino acids. Which is perfect because 10 grams of essential amino acid translates to about 20 grams of protein. So it nicely fits with those other studies. If he gave 20 grams of essential amino acids, there was no significant further increase over the next few hours. So that was normal response and in line with everything that we discussed before.

1:57:59If he did the same thing with the older population, he saw that that increase in muscle protein synthesis was less steep and also leveled off more rapidly. So that's how he coined antibiotic resistance. And that was I think 2005. Now it took our lab almost 10 years to verify or to confirm those data because we wanted to show the same thing with a less lab -based approach, not a sentient, with that 20 grams of intrinsically labeled protein. And when we actually finally managed to do that study over a long period of time, we saw that basal protein synthesis is not different between young and elderly.

1:58:41So if they're relatively active, basal protein synthesis, if there's a difference, it's actually higher in elderly than a young. But the response to the 20 grams of protein is less in the older population. So the same amount of protein that was ingested did not lead to the same amount of protein synthesis. And with the intrinsic level protein we could show that less of the ingested protein was converted to muscle. So that is also antibiotic resistance in a more single meal -like type of approach. Now the big question is, and this is now a lot of people are focusing on and antibiotic resistance, what is causing antibiotic resistance?

1:59:19That could be digestion. That could be absorption. That could be, and that's what they call, splanglyccecrestration, the uptake of amino acids, and what happens between taking up in the gut and releasing in the circulation. And of course, if scientists use difficult names, always beware, it generally means that they don't know what they're talking about. So when we go and say, splanglyccecrestration, everybody says, okay, but it just simply means we don't know to what extent the amino acids that were actually going to the portal vein are actually being absorbed in the intestinal tissues and not being released in the circulation.

1:59:57That's splangly sequestration. Where is it? Is it an liver? Is it still in the intestine? Is it taken to other tissues in between the portal vein, like lymphatic system? We didn't know exactly. And then the release in the circulation, but then insulin also plays a role because if there's not enough insulin and insulin is not stimulatory but permissive is how much of the tissues are being profunded so they get blood because if the blood doesn't perfuse the muscle those free amino acids are never going to be seen by the muscle. Then we have the uptake in the muscle and then you have those signaling responses empty apart by in the muscle.

2:00:34On all these levels anabolic resistance and scum resides. So it's impossible to find it. And so a lot of people are focusing on all these different areas. And then the problem is, and this is the problem with every study in where we actually look at aging, we compare young and older people. We don't follow the same person for 40 or 50 years because that doesn't work for studies. And it takes too long. That's why we use all those animal species or any organisms like these sea elegans or whatever. If we compare young and old, we're not comparing the same person. We're actually comparing lifestyle, comorbidity, pharmacological interventions that they have, food and take, all of these things.

2:01:18But I just said that physical activity makes the muscle more sensitive to the antibiotic properties of amino acids. Does it make perfect sense to say that less physical activity makes the muscle less sensitive to amino acids? So the only way to study this, and this is what we do is we immobilize young people. So we put one leg in a cost for a week. And then if you didn't believe the story about one to two percent turnover of muscle, you know, because even after a week when the cost comes off, you don't need an MRI scan to see which leg had been in the cost because you actually see the muscle as the loss of muscle in that leg.

2:01:56How much do you have to pay a young person to subject themselves to a week in a cast? Oh, to be honest, that is actually so one One week is, I mean, six weeks will be difficult, especially with health sciences and medicine, a lot of the students are active, but one week they actually love the experiments. I mean, now they can choose the color of the cost as well. So I think of some of the crazy experiments I got paid to do while I was in medical school. The time what I would do for a thousand dollars was I won't admit it publicly. Have you been able to study this longitudinally in a mouse, for example?

2:02:30No, so we only do animal -style human studies in vivo by hearty doing it. I mean, I do some animal work with collaborators. Is anybody studying this because again, you raise a good point, which is without a longitudinal assessment, which would not be possible in humans, we really are stuck without understanding the nuances. Of course, in humans, you can do a crossover between active and inactive, and that might provide an answer to the question. but as I listen to this list of differences in absorption, circulation, the splikening sequestration, which is, I'd never considered that, the perfusion related makes total sense uptake in the muscle, lower m -tore activity.

2:03:08We know m -tore activity is lower in the elderly. I think it could be any of the above. It could be all of the above. And what do I think that the really important? I don't think so. Yeah. At the end of the day, we know what you need to do. Control what you can control. Be more active. Consume more protein. But so if we take that previously immobilized lack and we give that person an amount of protein, I see a 35 % difference between the lack that was previously immobilized and the lack that was not immobilized. So there's a 35 % anabolic resistance after one week of inactivity. That is much more than we see as a difference between the young and the older.

2:03:51So with one week of an activity, I can make a young leg, a young muscle, respond completely like a senescent muscle. And out of fending, if I actually take an older person and I do some exercise in a given protein, I see a completely normal response. If I take a biopsy of an older person, I see smaller type two fibers. If I train that person for three months, the type two fibers bigger than the type one fiber, and I don't see any difference in the response to a younger person. And I can say the same thing about satellite cells. So muscle on itself is actually doesn't seem to get that old. It actually still responds completely normal, and I can normalize for age by physical activity.

2:04:37Yeah, I was about to say the two examples you gave there completely changed the discussion. Again, I think it's worth restating them because you're saying so many important things. I just want to make sure people are not missing these, right? So you took a group of young healthy people who presumably have lots of anabolic capacity. You put them in a cast for a week and you immediately demonstrate upon removing the cast that the leg that has been immobile for a week is 35 % less responsive to protein assimilation than the other leg. That's an antibiotic resistance factor of 35%, which you also pointed out is far greater than what you see in an aged individual.

2:05:21It depends whether that age is an active older or normal older. If that older person is lying in bed for three weeks with COVID, we're talking about not a situation, but yeah. But then the other thing you said was you can take an aged individual who might have, again, 20 or 30 % less antibiotic response to protein than a young person, but if you exercise them, you can bring them up to the same level as a younger person. These two factors suggest that activity might be the main determinant of antibiotic resistance, And an aging individual or age within an individual is simply a proxy for activity.

2:05:59And so it's more difficult for older people to maybe do the same training loads, but the muscle itself is still responsive. So the good news is you don't have to start exercising when you're 40 to actually have good muscle when you're 80. You can still do that at 70. Now it's better to do it at 40 as well. But at any age and that's also 100 plus the muscle is still very responsive to physical activity and It has nothing to do with hormones and that is also something that I get so fed up with We've just finished the study with prostate cancer patients now. You know what happens when they get energy in deficiency therapy They lose a lot of muscle mass.

2:06:43They gain a lot of fat mass. They have an increased risk of becoming diabetes developing cardiovascular disease, besides the effects that they become a little bit lethargic, we did training with them, resistance training, two to three times a week. The ADT had no effect on their muscle mass, they actually gained muscle mass. So despite the fact that they had no testosterone, they were basically chemically castrated, two to three times per week resistance training, increased muscle mass, increased muscle strength and attauated fat mass gain. It's that easy. It's ridiculous that people go on ADT and are not immediately getting resistance training in addition to it because it prevents all the negative side effects.

2:07:26You've now hit on the second point that I think is really frustrating and difficult to hear and I really hope that there are people out there in a position to do something about this, right? Which is look, there's such a disconnect in medicine when it comes from doing really wonderful things to then missing the boat on the support system that's needed. So the two examples here is the one you just gave. Does it make sense to put a man on androgen deprivation therapy? Yes, it does. Under certain circumstances. If a man has metastatic or inoperable high -grade prostate cancer, he needs to be on androgen deprivation therapy.

2:08:03And as you pointed out, yeah, as you pointed out, he is being chemically casturated. and I have seen many of these men and they are quite miserable because they are losing lots of muscle mass, they are gaining lots of fat and they are becoming metabolically profoundly unhealthy. And yet you would think that for every oncologist that puts a patient or every urologist who manages a patient through androgen deprivation therapy, it should be as important that prescribed alongside that end -region deprivation therapy is a resistance training program in a proper diet around high protein intake. And I would say, look, you should be resistance training four or five times a week.

2:08:48I mean, this is the most potent thing you have to counterbalance that. And the other example you gave that's just infuriating is to think of all of these sedentary hospitalized patients who are basically being protein restricted. Again, we talk so much in the United States, and I'm sure it's true in Europe about the cost of healthcare and the burden of healthcare and the burden of the sick individual and how so many dollars of a person's healthcare allotment are spent at the end of life when the quality is so low, and yet the system itself is broken in that it doesn't even understand the basic fundamentals of exercise and nutrition.

2:09:26And the funny thing about this that isn't really funny is this is what I think gives much of the population a total lack of trust in the medical establishment because they see, hey, you guys don't know about exercise and nutrition. So why should I believe you on these other things where you actually do have an authority? And I feel like I've seen an acceleration of this over the past few years. COVID clearly didn't help. We don't have to talk about why I think COVID policy eroded a lot of trust. But I think there's something even deeper than that, which is just a general belief that the medical system doesn't communicate through a strong position of knowledge when it comes to the real way to use exercise and nutrition as medical interventions.

2:10:12I think everybody knows that life's 1000 important, but they sometimes just do not realize how relatively easy it is to do it. And so we should have scientists and clinicians talk more. And it's changing, but it's very going very slow. Give you a nice example. I mean, when you're in the hospital, you get your nice meal at around five or six o 'clock if you're lucky, and then the next morning at, say, eight o 'clock or nine o 'clock in the morning. So you spent almost nine and six or 15 hours of fasting, 15 hours of fasting when you're at the risk of losing muscle. And you're not eating in those 15 hours.

2:10:50That's stupid. but not a single athlete in the world will do that. So we were wondering like, if you provide protein prior to sleep, does your gut actually process it while you sleep? Now, that sounds easy said and done. So we called some of our subjects and actually they call us, especially the elderly, they're really great to work with. It's amazing. So they call us and say, like, look, I haven't been to your lab in the last two years. Don't you have a study running that I can participate in? I would say like, oh, do it, must the answer come over? What we'll do is we'll take a muscle biopsy, then we'll take a laser gastric tube, put a tube down your nose into your gut, we'll make you sleep in the hospital overnight at 2 o 'clock in the morning.

2:11:31We will tiptoe into the lab, which 40 grams of pre -hated intrinsic labeled protein in your gut without waking you up. And in the morning, I will wake you up with a muscle biopsy. And then they say, where can I sign up? These guys are really amazing. But we did this and what happens if while they're sleeping and you provide the protein in the guts It's rapidly digested and absorbed just as easily as in the morning So there's no restriction there and they actually synthesize muscle protein at night Next morning we see the incorporation in the muscle. So when we published that study it was really weird I got phone calls from coaches all over the world asking me where they could buy those nasal gaseous And then I had to explain, I said, this is a proof of principal study to show you that the gut functions while we sleep.

2:12:19But if you want to do something, just give people a protein rich snack between dinner and going to bed because that will expedite reconditioning, help you with your recovery from training. And more importantly, it will might help older people or people in hospital to attain weight muscle loss while in hospital. Now, that's Part 1. Second part is, you actually start doing that with a protein, small protein snack in the evening, done then as well. Then the next step is, does it actually work in hospital? Because if you provide a protein -rich snack, do people still eat the same the next morning?

2:12:56Now that's already difficult because then in the hospital, this is actually not the invasive work that we do. I just wanted to have people bring around cheese cubes in the evening in the hospital and see how it affected 24 -hour food intake in patients. It went up by 20%. So that is stuff that we don't even manage with supplements, because people don't eat them. They get a supplement of the meal, it's just thrown away. So bring people a nice protein rich neck in the evening, the increased protein intake by 20%. It's that easy. We want to talk a little bit more about protein supplements. We've talked extensively about the milk protein isolate's way in case you're in.

2:13:37I get asked questions all the time about this and unlike you, I don't know the answer. So I'm kind of like, you know, my answer is, I don't think that matters. But for example, my wife's friends always ask me about collagen. Hey, should I be consuming this collagen or that collagen or this collagen? And my response is, I don't think that matters. I frankly think you're just better off consuming a high quality protein that has a balance of all of the amino acids. But tell folks, first of all, what collagen is. And then maybe answer my question about whether or not there's a unique benefit to consuming collagen as a supplement.

2:14:13I'm almost thinking like I should do less research. I don't get all these questions. So collagen is a protein that is pretty prevalent in your body because it's the main protein that is it's a structural protein. So collagen is in your cartilage, your bone, your tendons, your ligaments and all of that. And it's also in muscle, very small amount relatively. And it's important to transfer the force of your muscle towards your tendons. So even in the muscle, all of your contractile proteins need to be linked to collagen in order or connective tissue proteins in order to transfer the force. Now, a lot of people are in the market you see now in gesticology supplements because it helps you with strength, force, skin, bone, legaments and stuff like that.

2:15:05We're interested in because it's a very nice source of glycine and proline, about 50 % of your collagen is glycine and proline. So it's a poor protein from a total prospect of it, not as balanced as an animal derived meat protein or milk protein, but it contains a lot of glycine and proline. So what you could say is that, hey, your ligaments, your cartilage, your bone also contains a lot of glycine and proline. And so it's a good source of these two amino acids. Makes perfect sense. So the story makes sense, but it's a little bit like if you eat something that you need, it's going to be better for you.

2:15:41But the question is, do we already get enough glycine and proline in our diet and is additional via collagen or additional value. Now that is something that we don't know. We have been starting to look at this and so we have been ingesting collagen and weigh protein after exercise. And then we look at myofibler protein synthesis but also muscle -connective protein synthesis. And I hope that doesn't go too fast. Exercise stimulates both myofibler as well as muscle -connective protein synthesis. So the adaptive response in muscle is both connective proteins as well as myfibular proteins. Now if you ingest protein, it further increases the response to exercise and you see greater myfibular protein synthesis.

2:16:31However the ingestion of dairy protein or protein does not seem to increase muscle -connective protein synthesis rates. So so far at least for up to six hours after exercise, your contractile muscle responds to protein in addition to exercise, but your muscle connective does not. Now, we've tried that also with collagen, and we do not see a greater increase in connective tissue protein since its rates in muscle. So either it is not happening in the first five hours, and the exercise is already is stimulus enough and the response is later on or there's enough glycine and proline in dairy protein.

2:17:15How much are you seeing in the muscle -connective tissue response to dairy? I was in an impression, based on what you said, that it was virtually none. Is it some, but just pales in comparison to the exercise? It builds the comparison to the exercise, exactly. No significant increase in muscle -connective protein synthesis in addition to the exercise effect. Have you done this activity or this experiment without exercise? Because obviously exercise is such a potent stimulus that as you said, it might be dwarfing what we see. Have you done that experiment? Yes, we also done it without exercise and it does not seem to be responsive to nutrition, but I have to make an exception in that study by your, that huge amount of protein that hundred grams, we certainly see it.

2:18:00Interesting. So, in that study where you gave the massive dose of protein and those were not exercising patients. Over a longer period of time, yeah. But I was exercise as well. I see. So it seems that based on those data, there is no benefit in both myofibular or muscle -connective tissue protein synthesis using collagen versus using whey or casean. So if a person is taking a collagen protein, because they believe that it will disproportionately help them increase the strength of their or connective tissue, the data would say that that is not correct, at least in the presence of an exercising individual.

2:18:42Yes. Over five hours, I guess, to be fully complete. Yes. Okay. So from a practice translation, I still hold an option open for ligaments, tendons, bone, cartilage, because when I look at muscle -connective protein, a fraction that we actually take out of the muscle contains only a few percent of collagen. So the muscle doesn't contain a lot of collagen. So the question is, is it not more important for tendons, ligaments, bone and cartilage? I wouldn't say that it's not working there. So again, we are also at least, we're also patients, and we're also scientists. So as an scientist, I haven't seen evidence that it actually leads to greater connective tissue protein synthesis rates.

2:19:26But if I would actually break my hip or I would actually have a major issue with my knee and I'm recovering and Rehabitating I think I would take both a protein supplement that also has a little bit of collagen in order to be sure that I get enough glycine Primarily. The other point to consider is if there are people listening to this who are just using collagen as their supplemental protein source They're undoubtedly compromising myofibralur muscle protein synthesis because as you said, they're basically just getting a lot of proline and glycine and they're probably really missing out on lucine, lysine, methionine and the other amino acids that are far more potent.

2:20:07It's a very low quality protein from the perspective of amino acid balance. Yes, but it's a nice source of glycine protein But if you take enough protein probably the glycine protein is already sufficiently available in your diet However, if you have major issues with ligaments, tendons, or other almost purely collagen -based structures, it might be a benefit. I'm not throwing that away. That is something that we still want to look at for the next few years. But the jury is still out on that. Yeah. Let's talk a little bit about something you said earlier, which was what some targets might be for a meal.

2:20:43So you mentioned two to three grams of losing in a meal. if you really, really want to kick muscle protein synthesis into overdrive. Do you have any other rules of thumb around specific amino acids? One of the things we do try to talk to our patients about, especially patients who are plant -based, is rather than just have them worry about the different bioavailability of this protein versus that protein, it's just sort of focus on how much losing lysine methionine you're getting across the course of a day or even in the course of a meal. but I'd like to hear your guidelines around that. So many of the planned drive proteins are low in lysine and or metionine.

2:21:22So that is always a discussion, of course. Now, if you eat a lot of medalternatives, often these medalternatives lack or have a low amount of lysine or metionine. So a lot of these projects are spiked or fortified with those individual amino acids. However, if you eat a well -balanced meal, you typically have different plant -based proteins in your meal that often compensate low lysine or low methionine. For example, one protein has a high lysine and the other one has relatively high methionine, so they compensate. So that's why also your mom would say, have a diet that is balanced with a lot of different sources.

2:22:03Then the problems become smaller and you don't have to expect huge issues, certainly not if you're consuming enough protein because you can compensate for less equality by greater quantity. And that's also the confusion with, for example, the game changes documentary that everybody seems to have seen. If you have a huge football player and is consuming a massive amount of food, I couldn't even care less where the protein comes from because simply by the mass of protein, he or she already compensates for less equality by the simple mass, the large amount of protein. I mean, the hype is also here.

2:22:40I've got a phone call from somebody in the hospital saying, like, look, what do you think should we actually get only plant -based foods for our patients? And I'm thinking like, oh, no. Because equality becomes important when you actually have low quantity of food. So people that due to cancer or pain, eat less, don't give them high plant -based foods. It sounds like you're doing a good thing, but you're not helping them at that stage in life. Yeah, that's very interesting, right? You would think that the most vulnerable people, the smallest people, the people eating the least, the people who are in this case, greatest at risk for loss of lean mass need to disproportionately focus on the highest quality sources of protein.

2:23:24Everybody means well, and especially that's also the communication between clinical care and science that often you think like our plant -based diet is healthier. Yes, it's healthier if you're over -consuming energy. And so if you need a more plant -based diet, it will allow you to eat less energy, become less obese or less overweight. But that doesn't mean it's good for everybody, necessarily. Luke, I want to sort of before we wrap up, ask you one more question to think about until we meet again, hopefully in person here in Austin. Over the next 12 to 24 months, What is the single most interesting question you would like to explore in your lab?

2:24:03I don't think I could go to answer it in a year. I'll give this as a kickoff. It will start over with that one. We measured protein synthesis in brain tissue in humans. So people that have severe epilepsy, they get surgery in the brain, so the skull is lifted. These people were great. They actually wanted to participate in research. which are we infused, labeled amino acid tracer, and we actually got part of their neocortex. And we measured the synthesis rate of these amino acids in cooperation in the human brain throughout surgery. Turnover rate of the human brain is almost three times as high as muscle.

2:24:43And of course, there's slowly turning off proteins, they're fast turning proteins in your brain. But generically, on an average level, you can actually translate that into you having new brain in about three weeks. What do you still think you're you? I mean, that's interesting. Do all amino acids cross the blood brain barrier? I think so, but there might be differences on the large neutral amino acid transport is basically for all amino acids. Do you have any sense of which amino acids are disproportionately used by the cortex? No, so you're asking now, I mean, I'm not a brain physiologist, so we did measure, I mean, we published this in brain, I think about two years ago.

2:25:29I think the amino acid composition, if I remember correctly, of the brain was not that much different from muscle. Wow. But the turnover of your brain, and of course we know, is the brain has plasticity as well, just as you'll live her, just as and now we're also looking at tumors. So everything is growing and breaking down at an immense rate and I can't grasp my head around it because it means that everything is just doing this. And you don't notice it. Everything seems solid, but it's constantly broken down and built up again. The amino acids in your brain now might be in your toe tomorrow morning.

2:26:04How does the body do this and how do all these organs communicate? It's really amazing. Well, I think it is safe to say we won't have an answer to that question the next time we meet. But I think what we will have are some more questions and a deeper dive on this. So Luke, thanks very much for staying up late to talk with us this evening. Your time look forward to hopefully seeing you in person. And maybe you'll wear some orange for me next time in support of your amazing countrymen, Max for staffen. I will do so. Thanks for having me. It was fun talking. Thank you for listening to this week's episode of The Drive.

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Luc van Loon is an internationally renowned expert in skeletal muscle metabolism. In this episode, Luc starts with an exploration of the roles of insulin and triglycerides in endurance exercise, highlighting their impact on skeletal muscle metabolism, and he offers profound insights into the significance of protein in this context. He elucidates how different protein types and forms influence muscle protein synthesis rates, exploring the nuances of protein absorption, digestibility, amino acid quality, and their implications for performance and recovery. Delving deeper, he differentiates between animal and plant protein sources, unraveling the distinctive properties of various protein types, from the differences between whey and casein to the emerging trends in collagen protein supplementation. Moreover, Luc dissects the intricate connections among physical activity, lean muscle mass, muscle protein synthesis induced by resistance training, and dietary protein.

We discuss:

  • Luc’s background and insights about fuel selection during exercise [3:30];
  • Fuel utilization during endurance exercise [9:30];
  • Fat metabolism, intramuscular lipids, and the nutritional dynamics of endurance sports [17:15];
  • The optimal window for replenishing intramuscular fat stores and glycogen post-exercise [25:15];
  • Luc’s interest in protein metabolism and exploration of amino acids' dual role as building blocks and signaling molecules in driving muscle protein synthesis [32:15];
  • How protein metabolism differs between sedentary individuals and those engaged in predominantly strength training or endurance training [38:45];
  • The basics of how proteins are digested and absorbed, and how muscle protein synthesis is measured [50:30];
  • How factors like food texture, cooking methods, and protein composition impact muscle protein synthesis, and the importance of protein distribution throughout the day [59:45];
  • Differences in whey and casein proteins, and the ability of ingested protein to stimulate muscle protein synthesis [1:03:30];
  • Dietary protein distribution and quantity for the maximization of muscle protein synthesis [1:09:00];
  • Muscle loss with age and inactivity and the importance of resistance exercise to maintain type II muscle fibers [1:17:15];
  • Differences between whey and casein proteins, and the importance of both quantity and quality of protein sources [1:28:30];
  • Optimizing muscle protein synthesis: exercise, timing of protein intake, protein quality, and more [1:37:00];
  • How to preserve muscle while trying to lose weight [1:46:00];
  • Anabolic resistance and overcoming it with physical activity [1:55:45];
  • Importance of protein intake and physical activity in hospitalized patients [2:06:30];
  • Reviewing the efficacy of collagen supplements [2:13:30];
  • Plant-based diets: how to ensure a balance of amino acids, and other considerations [2:20:30];
  • Future research: understanding protein metabolism in the brain [2:23:45]; and
  • More.

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#299 ‒ Optimizing muscle protein synthesis: the crucial impact of protein quality and quantity, and the key role of resistance trainingThe Peter Attia Drive · 2 h 30 min
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