Essentials: The Science of Eating for Health, Fat Loss & Lean Muscle | Dr. Layne Norton

0:00Andrew Huberman:Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science-based tools for mental health, physical health, and performance. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. And now for my discussion with Dr. Layne Norton. Dr. Norton, thank you so much for being here. This is a long time coming, and I have to say, as a fellow PhD scientist, I feel a great kinship with you. I know you have tremendous experience in fitness and nutrition in a number of areas. I'd like to start with something that's rather basic and yet can be pretty complex, and that's this issue of energy balance and energy utilization.

0:41Andrew Huberman:What happens when we eat food of any kind, and how is that actually converted into energy as a way of framing up the discussion around weight loss, weight maintenance, weight gain, and body composition? It's a great question. And like you said, this is one of those things where people use the term calories in, calories out. And they say, well, that's way too simplistic. And I'm like, if you look at what actually makes up calories in, calories out, it's actually very complicated. So a calorie just refers to a unit of energy, of heat specifically. Really what you're talking about is the potential chemical energy that is in the bonds of the macronutrients of food, right?

1:22and by digesting, assimilating, and metabolizing those nutrients, we're able to create energy. The end product of that mostly is ATP, adenosine triphosphate, which is your body's energy currency. So a lot of metabolism is simply creating ATP. Protein's a little bit different because protein gets converted to amino acids, which can be used for muscle protein synthesis or protein synthesis in other tissues. But it also can be converted through gluconeogenesis to glucose. And there also are some ketogenic amino acids as well. Then you have fatty acids, which are able to create energy through what's called beta oxidation, where essentially you're taking these fatty acids and you're lopping them off two carbons at a time to produce acetyl-CoA, which again can go into the Krebs cycle, produce those hydrodions that can then power the production of ATP.

2:18So that's kind of like at the cellular level of how this stuff works. But stepping back and taking it back out, like what does that have to do with weight loss or weight gain, right? When you think about the balance of energy in versus energy out, sounds very simple. But let's look at what actually makes up energy in versus energy out. First of all, you've got to realize that the energy inside of the equation is more difficult to track than people think. So one, food labels, which we like to think is being, you know, like from upon high, can have up to a 20 % error in them. Really? Oh, yeah. The second aspect is there's what's called your energy, but then there's also metabolizable energy, right?

2:59So if you have foodstuff with, say, a lot of insoluble fiber, typically insoluble fiber is not really digestible. And so you could have, you know, quite a bit of carbohydrate. but if you can't extract the energy from it, and typically this is because insoluble fiber from like plant material, the carbohydrate or, and even some of the protein is bound up in the plant structure, which makes it inaccessible to digestive enzymes. And so this is what like adds bulk to your stool and whatnot. But again, reduces the metabolizable energy in there. And there's some evidence that based on people's individual gut microbiome, that some people may actually be better at extracting energy out of fiber compared to other people.

3:45So just starting off right there, okay, there's quite a bit of play in the energy inside of things. Now, one of the things people will say is, well, see, that's why you shouldn't worry about tracking calories because, you know, if the food labels can be 20 % off. And what I'll say is, okay, I understand where you're coming from, but typically if it's off, it's going to be consistently off. And if you're consistent with how you track it, eventually you'll be able to know kind of what you're taking in. So now let's look at the energy outside of the equation, which is actually way more complicated, right?

4:14And so your energy out is a few different buckets. The first one and the biggest one is your resting metabolic rate. So your RMR. That for most people is anywhere from 50 to 70 % of your total daily energy expenditure. Sedentary people will be on the higher end of that. So it'll be a bigger proportion, whereas people who are more active, it'll be a little bit lower, not because their metabolic rate is lower, but because they're expending a greater percentage of their calories from physical activity. Then you have something called the thermic effect of food, which is a relatively small percentage of your total daily energy expenditure.

4:48It's about five to 10 percent. Very difficult to measure. And usually what researchers do when they're kind of looking at this stuff is they just kind of make an assumption about it. They use a constant. And that refers to the amount of energy it takes to extract the energy out of food. You can't just eat food and then, you know, it just appears in your cells and you start doing stuff. It has to be systematically broken down and put into forms that can actually produce energy. A lot of times people will say something like, well, not all calories are created equal. That's not true because calories are just a unit of measurement, right?

5:22That would be like saying not all seconds on a clock are created equal. Yes, they are. All sources of calories may have differential effects on energy expenditure and appetite. So if we look at something like fat, for example, the TEF of fat is about zero to 3%, meaning if you eat 100 calories from fat, your net will be about 97 to 100.

5:42Andrew Huberman:So the process of breaking down that fat essentially subtracts some of the calories away because you used it in creating energy by breaking those chemical bonds to create ATP? Correct. Okay. Fat is actually the easiest thing to convert into energy. Then you have carbohydrate, which has a TEF of like 5 % to 10%. So you eat 100 calories from carbohydrate. And obviously, like the fiber content makes a big difference on this. But if you eat 100 calories, you'll net 90 to 95. Protein is about a 20 % to 30 % TEF. So if you eat 100 calories from protein, you're only netting 70 to 80. Now you're still net, you know, people say, well, you can't eat too much protein.

6:20Well, you know, people will ask, well, can protein be stored as fat? The carbons from protein, it's unlikely it's going to wind up in adipose tissue. But if you're eating a lot of protein overall as part of a lot of calories, it has to be oxidized and it can provide a calorie cushion for other things to be stored in fat. But protein itself does provide, you know, a net positive for calories, but less so than carbohydrate or fat and tends to be more satiating. So again, when people talk about, you know, are all calories created equal? yes, but all sources of calories may have differential effects on energy expenditure and appetite.

6:51So that's the TEF bucket and the BMR bucket. Then we go to physical activity. And physical activity is essentially two parts. There's exercise, which is kind of your purposeful movements. Like you go out for a walk, you do a training session, I mean, whatever, any purposeful activity. And then you have what's called NEAT, which is non-exercise activity thermogenesis. So for example, when I'm talking, if I'm waving around my hands, if I'm tapping my feet, if I'm whatever, that's NEAT.

7:20Andrew Huberman:The calorie burn from NEAT is actually pretty significant. We're not talking about 100 calories or 200 calories per day. We're talking about in some cases, hundreds of thousands, excuse me, hundreds to maybe even close to 1 ,000 calories per day. And what's very interesting about NEAT is that seems to be the most modifiable of BMR, TEF, and NEAT. NEAT seems to be far more modifiable. The next thing is a lot of people weigh very sporadically. And I'll tell people like if you're going to make an intentional weight loss a goal, and again, this can be different for different people. But typically I tell people weigh in first thing in the morning or I have to go to the bathroom, do it every day and take the average of that for the week and then compare that to the next week's average.

8:01As somebody who weighs themselves pretty regularly, I mean, my weight will fluctuate, you know, five, six pounds and not seemingly changing much, you know, and that's just, you know, Those short-term changes are fluid. So if you're somebody who just randomly is weighing in and you're eating in a calorie deficit and you just weigh in one day where you've just whatever reason holding some more fluid, then you go, see, this isn't working. When in reality, your average might be dropping. Weight fluctuations are actually identified as a major reason why people get discouraged from weight loss. It kind of stops the buy-in, you know, when they have a fluctuation up.

8:37So that's one of the reasons early on that low carb diets tend to work really well is because people lose a lot of water weight really quickly and they get that buy-in. So, oh, this is working. People think about, I'm going to do a diet and I'm going to lose this weight and they do not give any thought to what happens afterwards. Think about if you have some kind of chronic disease or a diabetic, right? You can't just take insulin once and that's it, right? You got to take it continuously. Otherwise, you're going to have problems. You can't create a new version of yourself while dragging your old habits and behaviors behind you.

9:09So what I'll tell people is, because people say, well, I'm doing a carnivore diet or I'm doing this diet or that diet. And I'll say, that's fine. Do you see yourself doing that for the rest of your life? And if the answer is no, you probably need to rethink what your approach is going to be.

9:24Andrew Huberman:Hey everyone. All right. My book is finally ready for release. Protocols, an operating manual for the human body is coming out in three months. It's my first book, and I've been working on it for many years now, and it's really a reflection of decades of research and experience that came even prior to starting the book. My goal for this book is that it serves as an easy-to-use manual for dealing with any number of different pain points or performance goals that you might have in terms of mental health, physical health, and performance. It covers the science and most effective protocols for sleep, nutrition, exercise, focused learning and neuroplasticity, stress management, and much more.

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10:37Andrew Huberman:Especially if your goal is like mine, which is to maintain or build muscle while also losing fat. I've been raving about the Carbon app to friends and to family and to members of my Huberman Lab team over the last few years. And everyone who's joined me in using it has found it to be tremendously useful. Now, there are a lot of apps out there that are focused on fitness and nutrition, but what makes Carbon different is that it doesn't just hand you a one-size-fits-all plan. It actually learns your metabolism over time, and it adapts your program based on your results. So if you're looking to take a smarter, more personalized approach to your nutrition, I can't recommend the Carbon app enough.

11:12Andrew Huberman:To try Carbon, you can go to joincarbon.com slash Huberman. While Carbon does not typically offer trials or promotions, they've agreed to give a free seven-day trial to all Huberman podcast listeners. Again, that's joincarbon.com slash Huberman to get a seven-day free trial. Could you briefly talk about how macronutrients, including protein, impact satiety from the standpoint of somebody who, for instance, would like to, quote unquote, lose a few pounds, right? Probably would be happy to gain a little bit of lean body mass, provided it was in a particular location on their body. That seems to be a thing now, directed hypertrophy, if you will.

11:49Andrew Huberman:And how much they should focus on protein as a core component of creating this diet. And are animal sources of protein, indeed, more bioavailable. That's a tricky word for sake of muscle building, but also for sake of somebody who just would like to lose body fat. They don't want to lose muscle and they'd like to bring their weight down a few pounds. Of the macronutrients, protein is definitely the biggest lever that you can pull. Because even if, you know, it doesn't take a ton of protein to get a lot of the muscle building benefits. I mean, I think the benefits really start to plateau out around 1.6 grams per kilogram of body weight.

12:22There's some evidence that maybe even up to like 2.4 or 2.8 grams per kilo may give like a little bit more benefit. I think it probably looks something like an asymptote in terms of a curve where as you put more into the system, you always get a little bit more, but it just gets to the point where it's so infinitesimally small benefit that it's for all intensive purposes, no benefit. There doesn't seem to be really downsides to it. Even like up to very high levels of protein, Jose Antonio did a study there was a year-long randomized control trial. And again, it's just one year, but they were looking at all sorts of different biomarkers.

12:56And basically even up to like four grams per kilogram of protein, they couldn't really find any negative health outcomes from it. Other than people were just so satiated, they ended up eating less calories. So protein is a big lever because one, it has a higher thermic effect of food. So you're getting a little bit more calorie burn per day, even though it's not a ton because TEF is a pretty small percentage of your overall energy expenditure, but still a benefit. You're getting the effects on lean body mass. It's going to, if you're in a diet, it's going to help preserve lean body mass. If you're at maintenance, it's going to help build a preserved lean body mass.

13:28And if you're in a surplus, it's going to help build a preserved lean body mass.

13:31Andrew Huberman:If I'm going to eat, let's say two grams per kilogram of body weight protein, and I'm not eating multiple meals, maybe I'm eating two or three meals per day. I'm certainly going to be eating more than the 30 gram threshold that was thrown around for a long time that we can only assimilate 30 grams of protein per meal should i just not worry about that some of it is going to go towards the thermic effect of food some of that might be converted into glucose of all things through gluconeogenesis so should i worry about this 30 gram cut off because i think balancing the the 1.6 gram per kilogram body weight threshold with number of meals with the need to exercise and work and live my life and sleep etc pretty soon you you run into bottlenecks yeah where you just can't do it all or you're spending so much time trying to focus You can't optimize all the things at the same time.

14:15You lose your mind and your body. Most Americans get about 65 to 70 % of their protein at dinner, right? Breakfast tends to be pretty minimal protein. So to answer your question, I do think that timing and frequency matters a little, not so much frequency, but distribution more so. But it's a much smaller lever than just getting enough total protein in. And then as far as like animal versus plant, I used to be in the camp of there's no way somebody can build as much muscle on a plant-based diet. And now I think I've come back to, you can, it just requires a little bit more planning. And I don't want to say always, but it's very difficult to do without an isolated source of protein.

14:53So unless you're going to supplement with an isolated plant source of protein, it's very difficult to get enough without going over on total calories because you can figure that, especially like take somebody who may be calorically restricted, trying to get enough protein from whole intact plant sources. So you've got a few different things working against you. One, the sources of protein you're consuming also have carbohydrate and or fat. Two, it's a less bioavailable form of protein. And three, it's a lower quality of protein in terms of it has typically less leucine, less branched amino acids, and less essential amino acids.

15:24Andrew Huberman:You answered the question that I almost interrupted you to ask, which was, does it boil down to the leucine content? And it sounds like that is one of the components and that a lot of the vegan and vegetarian sources of excellent protein, that excellent protein, vegetarian or vegan source is co-packaged with calories from carbohydrates and or fat that make it hard to stay under the caloric threshold. Whereas a steak is, I'm not, and obviously people might want to avoid that for ethical reasons, but that's a different matter entirely. But a steak or a piece of chicken or an egg is, well, an egg has a yolk, which is there's fat there, but is almost a pure protein fat source.

16:03Andrew Huberman:There's no carbohydrate along for the ride. You know, you can do it. It takes a little more planning. And you're almost always, if you're a vegan, especially, you're going to be better off like supplementing with some isolated form of protein or vegan form of protein. Now, this is where it gets into people say, well, what about the limiting amino acids and those sorts of things? It's a consideration. Some of the better forms of vegan protein in terms of amino acid content are like soy. Now, I can hear everybody screaming online about their testosterone levels. in terms of actual outcomes and looking at testosterone, there was a recent meta-analysis looking at soy.

16:39And I think if it's your only source of protein, then maybe the dosage is high enough to cause some weird effects. But if you're just using it like once or twice a day, it doesn't seem to have an effect on testosterone or estrogen. So that can be a decent source of protein because it is a complete protein source. It does have a PD-COS of one, which PD-COS is basically a a measure of protein quality based on does it provide enough of all the amino acids so that none are limiting. And so soy is one of the only vegan sources that does that. Interestingly, potato protein isolate actually has a similar essential amino acid content to whey.

17:17So isolated potato protein, it's just really hard to find. Another reason using an isolated protein can be helpful is because it's more bioavailable as well when it's been isolated out. When it's the protein bound up in the actual plant material, it tends to be less bioavailable. Now, cooking can help increase the bioavailability because it breaks some of those bonds and whatnot. The other thing to consider with the vegan sources of protein is the leucine content. So one of the studies we did was we looked at wheat, soy, egg, and whey, isonitrogenous, meaning we equated protein between the groups, isochloric, we equated calories, and we looked at muscle protein synthesis.

17:55and I think this was, the meals were 15 % of total energy from protein. So like your food guide pyramid level of protein. And we saw that in the wheat and soy group, they did not increase muscle protein synthesis, but the egg and whey group increased muscle protein synthesis. Now, what's really interesting is we went back and we took wheat and added free leucine to it to match the leucine content of whey and the protein synthetic response was identical. So, again, I don't like to simplify things too much, but leucine appears to really be driving this ship. A few different options for the vegan folks out there.

18:35You can use an isolated source of protein. And again, like there's going to be good options coming because this plant-based whey is going to be a great option for folks. You can add free leucine to it, to whatever your source of protein is. Just buy supplemented leucine powder. Now, it tastes horrible. It's completely nonpolar. It does not dissolve in anything. It can be put into capsules. Gross. It can be put into capsules. Yeah. So you could take a capsule. Like, for example, if you're eating your normal meal, you could just take a capsule of like one gram of leucine. It's probably going to bump you up enough that you're going to be good to go.

19:08There's options like blends, especially with corn. Corn is actually very high in leucine as a percentage of its protein. Now, you got to remember, like, you go eat corn on a cob and you're getting like two grams of total protein. So it's not that much leucine. But if you isolate out the protein, put it into a powder, well, now, you know, when you're getting like 80, 90 percent of the weight is now protein, corn is actually about 12 percent leucine in terms of the protein. So a great source of leucine, it is like almost frank deficient in some other amino acids, but you can blend it with a few other sources of protein.

19:40Like you could blend it with a soy, a pea, and you can create these complementary blends that would actually have quite a bit of leucine, but also some of the other essential amino acids. So there are options out there for plant-based folks. And, I mean, we have seen people who are plant-based build impressive amounts of muscle. There's quite a few bodybuilders that are plant-based.

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21:50I would 100 % agree with what you said, that trying to focus on minimally processed foods is very important. The one caveat I would say is I think it's important to understand why. Processed food just gets people to spontaneously eat more. Kevin Hull showed this in his study that was very, I mean, he designed some of the most elegant studies in nutrition. They basically took people from a minimally processed food diet and then gave them access to ultra processed foods. Very few instructions, just eat till you feel satisfied. And they spontaneously increased their calorie intake by 500 calories a day.

22:23That's massive. Now, that being said, it depends on the individual and their goals. If your goal is to, for example, build muscle or maintain a high body weight for a sport, for example, like an NFL offensive lineman or something of that nature, your protein, your fiber, your micronutrients, these are your responsibilities. But those become much easier to hit when you have higher calories. If you're eating 4 ,000 calories a day for whatever goal you have, you're probably going to have some left over. And like, good luck eating 4 ,000 calories from minimally processed foods. Quite frankly, you'll be miserable because you're going to have such gut fill that you're going to feel like you can't even move.