Q&A Deep Dive: Measuring Fat Loss, Testosterone vs. GainzZz, the Carnivore Diet, and More

0:04Welcome back to the Barbell Medicine Podcast. I'm Dr. Jordan Feigenbaum. This is a preview of some of the additional content that we regularly send out to our Barbell medicine. plus subscribers. And if you like what you hear, you need to join. Subscribers get the full ad-free experience, a ton of bonus content, and on top of all of that, massive discounts to include 25 % off all courses and seminars, 15 % off consultations, 10 % off all of our programs, early access to podcasts, and that's for about the cost of a cup of coffee for Austin and I. All right, that's it for the pitch. On to the show.

0:43John Rhodes, caller, what's your question? For the average recreational lifter, at what body fat percentage would you recommend they start a cut? This is actually a really interesting question. So this might – we might take a tangent here as I am prone to do. But one of the metrics, the measurements that we use to screen for obesity is body mass index, BMI, right? And it gets all sorts of hate all over the internet. People, BMI is BS, BMI is this, that, and the other. None of it's positive. Nobody is like taking up the cause for BMI. And I think that's unfair for a few reasons. One, it assumes that there's something better out there that we could be using instead.

1:28And it also assumes that BMI is doing a bad job at what it's intended to do. And in this case, BMI is designed to be a screening tool for identifying those who are carrying too much body fat. And the cutoff that we use is 30. So, you know, generally when people are complaining about BMI, they're like, I have a BMI that says I'm overweight. And I'm like, well, I don't really care about that. 30 is the number I'm working with to identify if somebody is carrying too much body fat. Below that, maybe at risk, but 30 is the line in the sand that we draw. Now, the real problem with BMI is that it does not catch enough people.

2:10A good screening test should catch everybody with the thing you're screening for and have some false positives. That would be a very sensitive test. And then you would use additional testing to rule out people who are falsely identified. Now, the problem with BMI is not that it identifies too many people. It's that it doesn't identify enough people. It misses about half of folks who are carrying too much body fat, but their BMI isn't 30 yet. There are other problems within different subgroups, subpopulations, who we either don't have great evidence on or their evidence is more mixed. And so the cut points would change just a little bit.

2:50But by and large, a BMI of 30 is very specific for excess adiposity, excess body fat, meaning that if somebody has a BMI of 30 or over, it is highly likely that they are in fact carrying too much body fat. And people say, well, what about the jacked bodybuilder? What about the person, the athlete who's super muscular? I'm like, how many of those people do you actually see? This is like a statistical aberration. But sure, that can happen. But we're really talking about less than 5%. And so a test, you know, screening test like BMI can be viable. So the main problems with BMI are that we don't have complete data on all populations and that it misses a lot of people who are carrying too much body fat, but their BMI is not greater than 30.

3:32So using waist circumference, we can help sort of shore up that deficiency. And so how this ties into body fat is that people say, well, why don't we just test body fat? Look, everybody can get a DEXA scan or use a BOD pod or BIA, something like that in the medical office. We could just directly assess body fat cut points. But we do not have good evidence suggesting firm cut points for various body fat thresholds and their correlation with disease. But we do have that for BMI. So like the World Health Organization has put forth that like men, 25 % body fat is like if you're above that, you're carrying too much body fat.

4:10Your woman is 35 percent. But these are mostly arbitrary, made up. They're not based in evidence, meaning that they've been correlated through with multiple populations and multiple disease states. It's just the amount of data we have correlating specific body fat levels with disease state is – we don't have a lot of data there. Not very good. So all of that is to say, to answer your question, I don't really use a body fat number. There's a few issues. One I alluded to just earlier, that we don't have cutoffs for specific body fat levels and specific testing methods to say, ah, you are at higher risk of disease.

4:49I mean, sure, if you wanted to say 25 % for men, 35 % for women, great. You can use that, but we still don't. That's just – it's still arbitrary. The other problem with body fat is that – like measuring it is that you can measure it so many different ways, and it's not – most ways that we can measure it aren't very accurate for actually monitoring changes in body fat. fat and lean body mass, though people will say that they are, and that is not the case. Good for populations or larger groups of people, but not great for monitoring an individual, like a DEXA scan. I would not do serial DEXA scans to try to ascertain if I was gaining more muscle mass or small changes, relative changes in body fat.

5:29It's just not set up to do that. It, yeah, a lot of issues with that. I'm not really concerned about radiation. That's a whole nother thing. In any case, so what I use for body fat sort of cut points for people when I'm working with them on nutrition or if somebody is asking me, if your BMI is above 30, I have concerns with that. Outside of individuals who are using multiple anabolic agents, yeah, I don't expect your BMI to go above 30. So that's kind of like a do not pass go, do not collect$200. There's some wiggle room there, but that's, you know, a line in the sand-ish. A harder line in the sand is waist circumference for men, particularly of European descent.

6:11If your waist gets above 37 inches, I don't like that. I think it should be less than that, less than 35, 34 inches, something like that. For really tall folks, I might be a little more liberal there. But yeah, so those are two kind of lines in the sand, two criteria you can use. And then the presence of any sort of adiposity-based chronic disease. Basically, that's the way of saying any sort of medical condition from carrying too much body fat. High blood pressure being like one of the most common ones associated with too much body fat is one of the first things that shows up. But people can also have issues with their fasting blood sugar, people who have issues with atherogenic lipids, so high LDL, high triglycerides, high APOB, things like that.

6:53So those are the things I'm using in practice to sort of monitor like, is this person gaining too much body fat or are they carrying too much body fat? Like, you know, we should probably go the other way. I think that's a better way to go about it than actual just body fat numbers. John Broci, what's your question, caller? Stretching doesn't seem to decrease injury risk or have muscle adaptation, but it can help with dealing with pain symptoms such as radicular pain. Oh, that's a question. I just put the wrong inflection in there. Any benefit worth pursuing? Cheers. Yeah, so the way I view stretching is it is a – or mobility work.

7:31We'll just use that umbrella term. It is a training modality designed to or with the goal of increasing a person's access to a particular range of motion or posture or both. And that can be useful in certain sports. I'm thinking gymnastics, figure skating, other ones where mobility is part and parcel with high levels of performance in the sport. it can be negative if it takes away from training time right because it does limit training load that actually goes towards like strength hypertrophy cardiorespiratory fitness and then as far as on in the middle between those two poles if this is a continuum it doesn't yeah as you mentioned it doesn't decrease injury risk it doesn't seem to reduce performance.

8:25I don't know that the decrease in performance that happens with acute stretching is really meaningful. It doesn't really matter to me. And it does take up training time that could be better spent training or doing something else. So its main use to me is either the pursuit of a particular mobility related goal that is otherwise not addressed in somebody's training, or as a entry point for somebody with significant pain who otherwise is unable to achieve the training load that they need. And so an example would be if somebody's got low back pain and you're like, yeah, I want you to deadlift from, you know, mid thigh, right, with the tempo.

9:05And they're like, great, that, you know, I've decreased the range of motion, I'm lightening the load with higher reps, maybe using a tempo, whatever. So I'm doing all these things to find my entry point. And they're can't do it at that point some stretching may be useful uh as a as to to get them either able to train or as even more of a regression um to gradually build from there but otherwise i don't think that people should be spending a lot of time stretching i don't think that it is a good use of training time when most people would benefit from more training than they would more stretching Nathan Smith, what's your question caller?

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10:53Good question, not a super unique question because this is the goal of basically everybody who's trying to lose weight who's also interested in strength and performance or just performance generally speaking. So first thing, from a dietary perspective, the only way that you can go from 105 to 97 kilos is a calorie deficit short of fluid restriction. But that's not going to last very long because you'll have to see Dr. Baraki or similar in a hospital. You can't do that. So, yeah, it's got to be an energy deficit. Generally speaking, you'd want to keep protein relatively high. And so, you know, 1.4, 1.6 grams of protein per kilogram body weight per day, maybe a little bit above that, but that's fine.

11:35Anything more than that is personal preference, whatever. And then don't follow a low-carbohydrate diet. Bad for both strength and for muscle retention, although there are issues with defining what a low-carbohydrate diet is. But just if you're thinking about doing this keto, probably wouldn't do that. I would go with a modest calorie deficit, 100, 200 calorie deficit from maintenance. You have a calorie calculator on our website you can use, also a macronutrient calculator on our website you can use. And so I would go low and slow with that. As far as the strength, I think that's predominantly related to programming.

12:09If your programming is not good, sometimes that can be kind of overshadowed or cloaked by people who are gaining weight, particularly rapidly gaining weight, particularly if they're untrained or previously are coming off a layoff, something like that. But yeah, it's mostly programming related. We have really good evidence that when exposed to a low energy availability, especially in the short to medium term, humans are very resilient to maintaining performance, if not improved performance, if the training is moderated correctly. So both the dose of the training and the formulation of the training has to be correct.

12:51I did an interview with Dr. Jose Arrita on this. I forget what podcast that was. But effectively what he looked at was, look, if you give people an energy-restricted diet, athletes, what happens? And by and large, they do just fine. And so I think there's just this thought that if you're trying to gain strength and you're losing weight, that those things compete. And on some level, they do, especially long term, because you do need to gain more muscle mass to effectively maximize your strength potential. You know, you need to increase the functional unit of a muscle to create force. Yeah, you can get better at contracting the muscle.

13:31You can get neurological or software updates related to improved strength. But the hardware has to be updated, too, over time. And so if you're in an energy deficit compared to maintenance, compared to a surplus, sure, you're gaining less muscle within a deficit compared to maintenance and maintenance compared to a surplus. But you wouldn't be on a diet for perpetuity, like an energy-restricted diet in perpetuity. It would be a focused period of weight loss, and then you go to maintenance. And then at that point, I think you can generate enough requisite hypertrophy to support strength improvements.

14:06But while you're losing weight, sure, some sort of compromise in muscle mass that you gain. But I think for most folks, they're able to gain enough muscle and gain strength if the programming is correct. Reeves2323, what's your question, caller? Can heavy barbell training for men in their late 40s or 50s potentially cause heart problems, specifically PACs or other abnormalities? This is an easy question to answer. Generally speaking, no. The cardiac adaptations related to resistance training tend to be beneficial. There is some thought that with high volumes of exercise, and this is not related to resistance training because you just can't do this much training.

14:54It's related to like ultra endurance, endurance training, very high volumes, that it can increase the risk of arrhythmia, specifically like atrial fibrillation, but not resistance training. So generally speaking, no. And it doesn't matter if it's heavy or if it's light, you just can't do enough of it, enough volume for it to really cause these things. And so obviously people have underlying conditions, this, that, and the other. And if you have these things, would definitely speak to your physician about them, but it's not related to resistance training. I feel pretty confident in saying that this sort of extreme exercise hypothesis, where doing exercise past a certain point is actually deleterious or harmful to health.

15:35It's mostly centered around that people can develop AFib. However, the improvements in fitness and subsequent improvements in other health metrics like resting blood pressure, fasting blood sugar, blood lipids, this, that, and the other tend to offset this increased risk of atrial fibrillation, which can also be treated. So it should be treated, it should be managed, it shouldn't ignore it. But, yeah, really not related to resistance training at all. Yeah. Tell me your favorite factoid about testosterone. Oh, interesting. Favorite factoid about testosterone. I mean, I think this is not – shouldn't be new to a lot of people listening to this.

16:19But, you know, testosterone has been sort of mythologized where people are like, I have to get my testosterone levels high and I have to make sure they're optimal. And then the reason that and because higher is better and the reason why I think that is because men have more muscle than women and it's because of testosterone. Now, some of that is true, but if you take a man and a woman and you expose them to the same training intervention, they will both gain the same relative amount of strength and the same relative amount of muscle mass in response to training because testosterone levels don't really matter that much.

16:58the testosterone, the way that testosterone reacts in the body, the androgen receptors are already saturated in both situations at relatively low levels of testosterone, which is why we don't see higher and higher amounts of muscle mass being gained or strength being gained when people are in the normal reference range for testosterone. And so when you look at the, not only the absolute differences are actually pretty small between the amount of strength and muscle mass that women and men gain, but the relative amount. So is it 10%, 20 % or whatever? It's effectively the same between the sexes, which clue you in on the relative importance of testosterone to training, provided a person doesn't have testosterone deficiency.

17:39Yeah. That's probably my favorite factoid that men and women will gain the same relative amount of strength and muscle mass in response to training because testosterone is less important than we think. Obviously, if it's lower, that's problematic. but yeah, it's not as important as people think. Some other interesting stuff, testosterone is involved in calcium modulation at the level of the muscle tissue and so if a person does not have enough testosterone, their actual muscle contractility decreases because their muscles aren't releasing enough calcium to go through the sort of force production cycle.

18:21Anyway, pretty nerdy there. Darshman, what's your question, caller? Eating carnivore, is there such a thing as too much protein? I mean, if you ate so much protein that you displaced essential fats from your diet, theoretically that's possible. Rabbit starvation, I think. Anyway, the biggest problem with carnivore is as follows. One, generally when people are following the carnivore diet, they are eating far too much saturated fat from animal sources. butter, red meat, et cetera, that on balance are not very health promoting at high amounts. Look, if 10-ish percent of your daily calories come from saturated fat from those sources, that's probably fine.

19:07But if it's 20%, I start, yeah, I don't like that. So that's thing one. Thing two, there's not a lot of vegetable matter. So it means fiber levels are low. And again, when we look at data from real world people eating low fiber diets, not very good. Now, people will argue about these data sets and say, well, look, the people who don't eat a lot of dietary fiber, they're generally eating a lot of processed food. That's not what we're talking about here. You got to compare apples to apples, not apples to oranges. And sure, you could do a carnivore diet in a more health promoting way. It would not have a lot of red meat in it.

19:41It would not have a lot of saturated fat from animal sources. It would have more vegetable matter with higher fiber in it. But yeah, I'm not really concerned about the protein intake. I'm not really concerned about most people's protein intake to be honest. I just think with respect to carnivore, I think that the way it is typically advertised and typically done is not consistent with a very health-promoting dietary pattern. It may be healthier than somebody's previous dietary pattern, but there are better options out there that generally are more plant-based and carnivore diets are typically not.

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20:45Thanks for listening. We'll catch you next time.

21:09We'll be right back.