Dr. Gabrielle Lyon argues we’ve been focusing on the wrong idea for 50 years…the problem isn’t that we’re over-fat, it’s that we’re under-muscled.
Skeletal muscle makes up 40% or more of your body and is an underrecognized endocrine organ that secretes myokines (signaling molecules) when contracted, impacting the brain, liver, pancreas, and truly every body system. Yet skeletal muscle wasn’t even considered an organ system until about 25 years ago!
The diseases we think of as obesity-related—type 2 diabetes, Alzheimer’s, cardiovascular disease—are actually diseases of skeletal muscle first, decades before symptoms appear. When Dr. Lyon asked a PCOS expert what body fat percentage contributes to infertility, the answer shocked her: “It has nothing to do with body fat percentage—it has everything to do with the fat infiltrated into the muscle, the intermuscular adipose tissue (IMAT).”
The new US Dietary Guidelines (which Dr. Lyon witnessed being announced on stage) recommend 1.2 to 1.6 grams of protein per kg for the first time in history, a tremendous change based on randomized controlled trials instead of epidemiology. Her mentor, Dr. Donald Layman, wrote the protein portion of the guidelines, and 90% of those guidelines are reflected in her new book, Forever Strong Playbook, released on January 27th of this year.
Table of Contents
In this podcast, Dr. Lyon and I discuss:
- The problem isn’t that we’re over fat—we’re under-muscled—obesity is a symptom of unhealthy skeletal muscle first, not the root problem
- Skeletal muscle wasn’t even considered an organ system until 25 years ago, yet it makes up 40%+ of body weight and is the only organ we have voluntary control over!
- Type 2 diabetes, Alzheimer’s, and cardiovascular disease are skeletal muscle diseases first, decades before they manifest as obvious health problems
- PCOS and infertility have nothing to do with body fat percentage…Dr. Lyon shares this perspective from a trusted PCOS expert
- Body fat percentages will be an obsolete biomarker within five years; muscle quality and intermuscular adipose tissue matter far more than total body fat
- When at rest, muscle burns primarily fatty acids, not carbohydrates…it only burns 2-3 grams of carbohydrates per hour
- The new US Dietary Guidelines recommend 1.2 to 1.6 grams of protein per kilogram of body weight; for the first time in history, based on randomized controlled trials instead of epidemiology (Dr. Lyon’s mentor wrote the protein portion of the guidelines)
- By age 40, 40% of men have erectile dysfunction, 50% by age 50, but healthy skeletal muscle mass improves sexual function (Dr. Lyon published one of the first papers on this relationship)
- The older you are and the more sedentary you are, the more protein you need—this is counterintuitive but true due to anabolic resistance (muscle becoming less efficient at sensing amino acids)
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Transcript
Ari: Hey. This is Ari. Welcome to The Energy Blueprint Podcast. I’m really excited about today’s episode because I’m speaking with a good friend of mine and a repeat guest, someone whose work I believe is absolutely essential. That is my friend, Dr. Gabrielle Lyon. She is a Washington University Fellowship-trained physician in nutritional science and geriatrics. She’s the founder of the Institute for Muscle-Centric Medicine. She is a New York Times bestselling author of the book Forever Strong.
If you haven’t heard our previous conversations, Dr. Lyon has made the case, and I think very compellingly, that we’ve been asking, essentially, the wrong question for the last 50 years. The problem isn’t so much that we’re over fat. The problem is that we’re, in her words, under-muscled. That simple reframe really changes everything about how we approach metabolic health, energy, aging, body composition, and disease prevention and longevity more broadly.
In this conversation, we cover a lot of ground. We talk about why skeletal muscle is the organ of longevity, why it’s not just about movement and strength, but also about how muscle is the largest endocrine organ of the body and secretes hundreds of signaling molecules that affect the brain, the metabolism, the immune system, virtually every system of the body. We get into optimal nutrition for muscle health, protein recommendations, the new government guidelines.
We also cover some controversial territory around protein, some of the debates among the dietary camps, veganism versus carnivore, and all the stuff in between those two. The ideas around protein and mTOR, protein and kidney health, protein and cancer, and several other related issues to that. We discuss her new book, which, by the time you see this, has just come out a few days ago. As of this recording, it’s coming out tomorrow, on January 27th.
That is the Forever Strong playbook, which is her brand-new, awesome, practical six-week program with the actual protocols, recipes, and exercises that she uses with her patients. Now, I’ll be honest with you, when Forever Strong came out, I bought a copy for myself, and I also bought copies for my parents because I think this is a critical component of health and longevity. This message around this new understanding of muscles, not just as being there to be strong or to look good, but as being central to health and longevity.
That’s how strongly I feel about this message. I bought multiple copies. I’ve done the same here. I’ve bought a whole bunch of copies of her new book to give to my parents, my wife’s parents, and really everybody that I know, because I think this is just such a good, simple, yet evidence-based practical manual to optimize your muscle health. I think that skeletal muscle is arguably the most underappreciated organ in all of health and medicine, in all of health science more broadly.
I think Dr. Lyon is really leading the charge to change our perceptions of that. I’ve known her for many, many years, long before she became a New York Times bestseller, long before she was popular, and the trendy new author on the scene that’s blowing up. It’s been a joy to watch her success, and I am really happy to be involved in supporting her and supporting her work and helping her get the message out. With all of that said, I hope you enjoy, and I know you’re going to get a lot of value from this podcast. With no further ado, enjoy this conversation with Dr. Gabrielle Lyon. Dr. Lyon, such a pleasure to have you back on.
Dr. Gabrielle Lyon: What a fun experience getting to see you again.
Why skeletal muscle is worth paying attention to
Ari: Yes, absolutely. I haven’t seen you in person in a few years at this point. You’ve been very busy. You’ve blown up on the scene at this point. You’ve got a New York Times bestseller, Forever Strong, and you’ve promoted this whole new vision of muscle-centric medicine, muscle-centric health, and positioning muscles as the organ of longevity. For people who are listening to this, for people who are unfamiliar with your work, tell us about this vision of why maybe it’s not all about what’s in our blood biochemistry, but we should be paying more attention to what our muscles are doing and what’s going on at that level.
Dr. Lyon: It’s really interesting. Skeletal muscle often has been thought about as this performance entity. You think about being jacked and tan at the gym and how to have more strength and power; all of that is important, but skeletal muscle, which makes up 40% or more of someone’s body, potentially could be less, really is an endocrine organ, meaning when you contract skeletal muscle, you have voluntary control over this tissue. It acts as an endocrine organ. It secretes molecules called myokines that travel through the brain, connect with the liver, connect with the pancreas, and really has systemic effects.
Again, why does that matter? People are like, “Well, I don’t really care, but the reality is, based on the contraction, intensity, and duration of training, you can transform someone’s entire system. As I think for the last 50 years or so, we’ve been fighting this obesity epidemic, and skeletal muscle really has not even come into the scene. In fact, skeletal muscle wasn’t even considered an organ system until 25 years ago.
If we’re not careful, we’re going to repeat history because, at the end of the day, obesity, type 2 diabetes, Alzheimer’s, cardiovascular disease; these are all diseases in part of skeletal muscle first. Decades before.
Ari: What was the last part?
Dr. Lyon: Decades before.
Ari: Decades before.
Dr. Lyon: These are diseases that really exist within skeletal muscle.
Ari: There’s so many different layers we could go into from here, but one of the things that we spoke about in our last conversation is the idea that it’s not so much that we’re over fat, it’s that we’re under-muscled. Tell people about that distinction.
Dr. Lyon: Yes. Now, typically, again, we focus on obesity as the problem, but the question is, is that really the problem, or is it a symptom of unhealthy skeletal muscle? I would argue obesity is a symptom of unhealthy muscle first. The question isn’t, are we over fat or are we suffering from an obesity epidemic? I would argue that it’s actually quite the opposite, that the majority of people do not have enough healthy skeletal muscle, and that is the ultimate problem.
Ari: How did we get into that situation? What do you see as the grander story of the epidemiology of how we became, as a society, under-muscled?
Dr. Lyon: It’s a great question. I think part of it is that, as humans, we become very good at seeing a problem, and that, as a collective, we create these cognitive biases. You’re like, “Okay, well, what does that mean?” Meaning that if we focus on obesity and the obesity epidemic as the problem that we have to solve, then everything becomes centered around this entity, and it’s all about what we have to lose.
There’s no guarantee how much body fat someone’s going to be able to lose. It’s very much outside of our control, but if we think about skeletal muscle as an organ system within our voluntary control, and the simple act of doing some type of exercise, whether it’s resistance training or cardiovascular activity, improves the health of this tissue. If you think about skeletal muscle like a steak that you would go and eat, there’s a fillet, and then there’s wagyu. You don’t want muscle to look like a wagyu. You want it to look like a fillet.
When we focus on fat as the problem, obesity as the problem, we orient ourselves to what we have to lose. I think that it’s been a massive failure for the last 50 years. As obesity as the problem, this makes it outside of our control, but skeletal muscle as the solution, what we have to gain, and how we can improve our health, and I’m going to explain to you what exactly skeletal muscle does, then we can solve for that, and it’s within our voluntary control.
I think it’s been one of the biggest failures, this idea that we have this obesity epidemic. Clearly, we have a body fat problem, but is that the actual problem, or is it the root skeletal muscle? I would argue that, within the next five years, we are going to find that body fat percentages is almost an obsolete, outdated biomarker. That sounds crazy, doesn’t it?
Ari: Take me through the logic of this. When I was a personal trainer in my 20s, we had this– what certainly you and I would now consider a very oversimplistic view of the relationship between muscle and body composition, which is everything is calories in, calories out. Everything is about, well, each pound of muscle burns, whatever it is, 9 or 10, 11. I forget the number.
Dr. Lyon: We’re going to come back to that. We’re going to come back to this statement.
Ari: Calories per day, even at rest, and therefore, if you add 10 pounds of muscle, then you increase your resting metabolic rate by X amount of calories per day, which over time leads to X amount of fat loss. Now, there is this new vision that you’ve alluded to so far in this conversation of muscle as an endocrine organ, muscle as a longevity organ, all these myokines, all these signaling, how muscle interacts with the other system of our body to do many more things, not just simply burn a few more calories at rest each hour, but there’s a whole big story of what’s going on.
How do you actually map out this link between what’s going on at the muscle level and what’s going on with our body composition, our body fat more broadly?
Dr. Lyon: Now, you’re always so eloquent, Ari, which is one reason why I just love chatting with you. If we take a step back, we’ve framed everything up in terms of obesity and muscle mass. Really, it’s obesity and sarcopenia, which they are two sides of the same coin. Obesity is—
Sarcopenia
Ari: Just define sarcopenia because some people might not know what that is.
Dr. Lyon: Sarcopenia is decreased muscle mass and strength. The way that we would picture that is, say, our older parents or our grandparents, we see that they actually even get smaller, more frail, less capable. They walk slower. It’s difficult to pick up, say, a normal bag. This is not a normal trajectory of aging. The idea that we would have “sedentary, healthy individuals,” if someone were to go and look at the research, you might pull up some papers where they say, “Healthy, sedentary individuals.” There’s no such thing.
There’s smooth muscle in the uterus, there’s cardiac muscle, but skeletal muscle is the most obvious. It was designed to move, and it was designed to move against resistance. In fact, this is the cornerstone for its health abilities. It must happen. When we think about how we’ve looked at everything, we’ve looked at it through this body fat percentage lens, for example, like a DEXA. It started with BMI, which is Body Mass Index. This was used at a population level to be able to determine if someone was healthy or not healthy for, say, insurance purposes.
That, we would all argue, is not very sensitive. It doesn’t tell someone the real story of their body composition. Take it a step further, then we move to DEXA. We’ve all heard about what a DEXA is. It allows your physician, your healthcare provider, to look at body composition, namely fat and bone. It extrapolates the rest. The lean body mass is all extrapolated. It’s not measuring the quality of skeletal muscle or the amount directly.
Now, if we just pause for a second, this means we have decades of research without looking at actual skeletal muscle. This, as one would imagine, would really put skeletal muscle in the backseat. Then what does this mean going forward? It means that, because we haven’t been looking directly at muscle quality and mass, then when we begin to think about disease prevention, it’s really been kept off the table. Another way to put this is the simple act of doing resistance training actually improves muscle health regardless of body fat changes, regardless of muscle mass changes.
I am going to frame this up in a story. On my podcast, I was interviewing one of the world-leading experts of PCOS. PCOS is Polycystic Ovarian Syndrome. It is the number one cause of female infertility. There is a brain portion of it, and then there is a metabolic component of PCOS. There’s two major categories. I asked her. I said, “Dr. Cree, what is the body fat percentage that contributes to infertility? It’s got to be a percentage. Is it 30%? Is it 35%? What is that number?”
She looked at me, she said, “Gabrielle, it has nothing to do with body fat percentage. It has everything to do with the fat that is infiltrated into the muscle. It’s the IMAT. It’s the intermuscular adipose tissue that determines if someone is going to struggle with fertility or not.” That was an aha moment because we don’t measure that routinely. We don’t measure fertility in that, or we don’t measure body composition in that way. If we recognize that it is not body fat percentage, but really the percentage of fat within muscle and overall the muscle amount, this reorients us to, what do we need to do to solve for healthy muscle mass.
It’s not as difficult as people would imagine, which is why I put together this playbook, the Forever Strong playbook. It’s a tactical field manual for how to build strong and healthy muscles throughout your entire life. You had mentioned something about the focal point of health earlier in this interview. Metabolic syndrome, which is something that we test for in the blood— because you had mentioned beyond blood markers—elevated levels of triglyceride, elevated levels of insulin, and elevated levels of glucose, people associate with metabolic syndrome, with “obesity,” but it’s not.
It is an indication of the health of your skeletal muscle. When these numbers are abnormal, it’s due to a mismatch of your nutrition with your muscle health.
The connection between lipids and muscle tissue
Ari: Beautifully explained. You’re mentioning this story of lipids that have accumulated in the muscle tissue themselves. This is something we chatted a bit about in our past conversation, I remember. This is something I learned from listening to Iñigo San Millán, who’s an exercise physiologist and researcher. There’s this really interesting story of what’s going on with the lipids in muscle. I know you know what I’m getting at here, so I’m going to let you explain this because different demographics and how fat accumulates differently in muscle tissue.
Dr. Lyon: There’s something called the athlete’s paradox. First of all, let’s take a step back. What you said earlier, I’m very impressed. You said muscle really doesn’t burn a lot of calories at rest. You are absolutely correct. It doesn’t. It roughly burns around two to three grams of carbohydrate per hour. That’s nothing. If you imagine 50 pounds of muscle and it’s burning only 2 to 3 grams of carbohydrates at rest, you do the math [crosstalk]
Ari: How easy is that to counteract with having a bit of peanut butter or something like that?
Dr. Lyon: Exactly. This is really important because, at rest, skeletal muscle, its primary fuel source is fatty acids. At rest, skeletal muscle that is healthy is burning primarily fatty acids. The average American is eating 100 grams of carbohydrates. They’re doing 300 grams of carbohydrates a day. They’re doing three oral glucose tolerance tests a day. It is no wonder that we see elevated levels of triglycerides, which is really a carbohydrate problem, elevated levels of glucose, and elevated levels of insulin.
Imagine this, if we are sedentary and we’re having 300 grams of carbohydrates a day, again, this is what the majority of people are doing. Perhaps not your listeners, but I do think for their loved ones, and just for the health of our humanity as a whole, we have to understand these things, that if you are eating these carbohydrates and you are not engaging in some type of training, resistance, cardiovascular training, then your muscle glycogen is full. You’re never emptying the tank.
What happens is, over time, you create low levels of inflammation, you have higher levels of fatty acids, you have just higher levels of these byproducts that create a very unhealthy environment, and arguably, fast forward over years, you create fibrotic tissue. This muscle tissue progresses from the fillet to a wagyu, and then even worse quality meat, where you’ve got connective tissue and then a lot of marbling, which then decreases both the contractility of that muscle, but also its metabolic flexibility and its metabolic bandwidth and power, and this is the real problem.
As we think about reframing the conversation from obesity to muscle health, this is all a muscle problem. The obesity epidemic, these issues with type 2 diabetes, these are not inherent to obesity; it’s inherent to this mismatch of muscle health, which is why when we see, say, linemen or people that are very physically active, this is probably the biggest eye-opening perspective that I personally ever had, is I thought that if someone struggled with obesity, there’s no way that they could be healthy.
I was wrong because engaging in this physical activity, taking care of this organ of longevity, actually improves the health of this tissue and improves the metabolic flexibility regardless of body composition changing. I just think that it’s very empowering because someone listening to this might go through periods where they lose weight, gain weight, and that can be very disheartening as opposed to recognizing that, if you take the physicality, the look off the plate, the reality of just engaging and emptying the tank improves that muscle quality.
When you spoke to the exercise physiologist, you were talking about the athlete’s paradox. This is lipids stored around the mitochondria within muscle, and that’s just fuel. These people are highly physically active, that the turnover of energy is very fast. That is its own entity, but what we’re seeing with Intermuscular Adipose Tissue or IMAT and the decrease in muscle quality that, again, someone could be obese or not be obese, but if they have a ton of fat that is infiltrated into that muscle tissue, they are weaker, they are metabolically less flexible. You will see it in their blood work, and it’s going to set them up for a series of problems later on.
Ari: The athlete’s paradox is, as I think of it, three different demographics of people, where in the middle, I guess you could say, it’s convoluted because the average is now more skewed in the direction of being over fat, under muscled, and having this problem. Let’s imagine some in-between state of normal people who maybe don’t do much exercise, but are not necessarily over fat or under muscled, in between. They might not have a lot of this marbling, a lot of this fat infiltration of their muscle.
Then on the one hand, you have what you’re describing, people who are over fat, under muscled, heavy infiltration of fat into the muscle tissue. Then you have athletes, especially endurance athletes, on the other end, who have a lot of accumulation of fatty acids in and around their mitochondria inside of the muscle cells themselves. In other words, both extremes have a lot of fat in the muscle tissue. The difference is where the fat is located and also the flux.
In the athlete state, it is an adaptation that is designed to serve the fact that they do so much activity that burns those lipids. There’s a huge amount of inflow and outflow constantly. Whereas on the other situation, of people who are over fat and under muscled, and you get that heavy infiltration of fat, that fat is just stuck there and blocking muscle function. Is that accurate?
Dr. Lyon: That’s very well said. Yes. It’s important because, if you think about it, we don’t measure it right now. At a population level, you do not go to your doctor, and you say, “Well, I need my intermuscular adipose tissue measured. Where am I at? Is my exercise effective or not? Where do I need to really put in the effort?” I believe that we’re going to be moving there in the next five years, and that’s really through MRI, and there’s potential for ultrasound.
Again, this is not something that we do routinely, and it’s been a huge blind spot for us because it’s perpetuated this narrative that it’s all about weight loss and it’s all about treating obesity. It’s not. It’s all about treating muscle health and creating a diet, which is why I’m so excited about these new dietary guidelines, which have now reoriented us to the importance of protein. We, for the first time ever, have a countrywide acceptance, I’m hoping, of the importance of dietary protein as a component to health because, again, really health, and you talk about this in various ways.
By the way, there’s red light in the Forever Strong playbook. You definitely come at this from a very holistic view. When we think about it, there is a way to focus on muscle as this architecture and then build around it as opposed to trying to take the scaffolding off of a house; just build a house better.
Myokines
Ari: I want to come back to the dietary guidelines thing because it’s important. I don’t know how much you’re able to speak about your involvement in it or if it’s top secret. I’d love for you to tell listeners about that if you can. Before we get there, I want to talk a bit more about myokines because this whole discussion, this whole understanding of muscle as an endocrine organ, and the discovery of myokines, is really pretty new science. It seems like there’s new myokines being discovered all the time, and that we are building out more and more this understanding of what these compounds that are being secreted by muscle tissue are doing.
It turns out they do all kinds of things like combat various diseases and all kinds of other organ systems which might help explain why doing exercise, doing physical exercise and working our muscles, working our heart, working our lungs, why it doesn’t just combat diseases of those tissues that are being exercised, but why it has system-wide effects that combat all kinds of diseases in other areas like combats dementia, for example. It has effects everywhere in the whole system. Can you tell listeners a bit more about this myokine story and maybe some of the key myokines and what they do?
Dr. Lyon: It’s truly fascinating. You and I grew up in the era thinking about exercise as this release of endorphins, that people should do exercise because it improves the plumbing and the cardiovascular impact, and then we’re going to get endorphins. All of that’s true, but the next level to that is recognizing skeletal muscle as an endocrine organ. Endocrine organ is an organ that secretes hormones that both act systemically and locally and then on the tissue itself.
Muscle is that, and if people can think about that, it is an organ system, it’s an endocrine organ that we have voluntary control over. That just blows my mind. It’s the only organ system that we have voluntary control over. Imagine if we talk about the unhealthy tissue and the unhealthy tissue that has fat that is now infiltrated into this tissue. Then it becomes impaired in its release of these myokines, which, again, are these hormones that travel throughout. There’s hundreds of them.
For example, interleukin-6 is probably the most famous myokine. People will say, “Well, that sounds like a cytokine. That sounds like one of the molecules that is released from a macrophage,” and that’s true, but when it is released from muscle, it balances these levels of inflammation in the body. It also, in part, partitions fuel use, like carbohydrate use. It actually affects the liver. The exercise itself, it’s not just about the calories in, calories out, the exercise component, but it’s actually also the release of these interleukins and these myokines that contribute to fuel partitioning, the utilization of carbohydrates.
That adds in a whole level of complexity, but also a level of privilege and choice, which I think is just amazing. Then, from a brain perspective, when you exercise based on the intensity and duration, myokines like BDNF and irisin and capsaicin, these are myokines that cross the blood-brain barrier and improve neurogenesis. It’s like the fertilizer for the brain. The system-wide effect is above and beyond, and we’re still figuring out.
Oftentimes, we think about one of the predictors of osteoporosis is low muscle mass. People will say, “Well, when you contract muscle, you’re pulling on the bone that’s stimulating the tissue of the bone.” That’s true, but it’s also the myokines that stimulate the bone. Again, we have to remove ourselves from thinking it’s black and white in the way that it is just movement, and it’s the movement that makes the difference. Yes, the movement improves cardiovascular effects. Yes, the movement improves blood flow, but also, as an endocrine organ, we are activating this system that then improves outcomes in nearly all-cause mortality.
Nearly any cause of death, you improve your survivability based on the health of that skeletal muscle.
Ari: You just reminded me of a quote I like from John Muir, who said, “When one tugs at a single thing in nature, he finds it attached to the rest of the world,” because you’re getting at this profound interconnectedness. I think, even when we talk about things, and I love this kind of conversation where you start to connect the systems because so much of what goes on in modern medicine and modern health thinking is so siloed, so disconnected, every individual category is like its own little silo of information. The reality of human physiology is an interconnected system.
When I hear people making those connections, I’m like, okay, this is somebody who actually understands the nature of human physiology, rather than, “Okay, we look at thyroid health, and thyroid health is a whole story of just the thyroid.” It’s like, “No, we have to understand how it connects to everything else.”
Dr. Lyon: Think about your work, and also red lights, and just really this system-wide approach. Muscle has a 24-hour clock. Muscle is actually affected by light. It’s just so profound, and also, it makes up so much of our body weight that this tissue has to be healthy. We really have to get this portion right, or it’s going to be nearly impossible. For example, people, say cardiologists, will focus on the heart, and they’ll say, “Okay, well, the heart has to be healthy.” Well, yes, but the way that you leverage a healthy heart is through muscle. We actually just have to–
Ari: The story of even a healthy heart becomes so fixated on seeing it through a disease-centric framework, seeing it through a biochemistry-centric framework, that the whole story then starts to revolve around people start to think a healthy heart is about what’s floating around in my blood and taking a drug to alter what’s floating around in my blood rather than this much more expansive vision of what actually determines heart health.
Dr. Lyon: Yes. In fact, we have been working on a body of literature to help muscles recognition. I guess that’s the best way to say it. We recently published a paper, myself and some of my colleagues at [unintelligible 00:31:50]. I was a senior author on this paper, and it looked at sexual function and muscle mass and strength. 40% of men, by the age of 40, have erectile dysfunction. 50% of men by the age of 50 have erectile dysfunction.
Healthy skeletal muscle mass improves that. We published a paper on the relationship between muscle mass and sexual function. It’s one of the first of its kind. Again, why? Because it builds the evidence for muscle as this focal point.
Ari: Yes. Awesome. Interesting. I didn’t know that you were an author of that paper. I remember seeing that. When did that come out? A couple years ago?
Dr. Lyon: No, no, within the last year. We published another paper on testosterone in women and a handful of other ones. Yes.
Ari: What are the findings from the one on testosterone in women?
Dr. Lyon: It proved safety, basically.
Ari: Oh, taking exogenous testosterone?
Dr. Lyon: Yes.
Ari: Okay.
Dr. Lyon: It was a paper on pellets and safety profiles for women.
The new US dietary guidelines
Ari: Nice. Let’s go back to dietary guidelines for a moment. I saw the new dietary guidelines that came out very recently, and I’m almost in shock because I never would have– This is the way that I’ve been eating for three-plus decades. I’m so used to seeing the government guidelines being so focused on eating the foundation as processed grains and all this stuff. We’re supposed to have whatever it is, five to eight servings a day of grain.
Dr. Lyon: It was 12.
Ari: Yes. I’m just almost in shock looking at these new guidelines because I just never imagined the day that I would actually see the US government making nutritional recommendations like this that are actually good.
Dr. Lyon: Ari, I was there on stage as they addressed the American people. I have to tell you, it was one of the most emotional experiences. Aside from the birth of my children, I would say this was– I kid you not, it was up there. For those of you who don’t know, I’ve been friends with Ari. We’ve been friends for a very long time. I’ve been working on educating about protein for the last– I’ve been studying it for 25 years, but educating easily for the last 10.
This has been the mission. Behind the scenes, I was able to connect the dots for people. My mentor, who co-authored the nutrition section of this Forever Strong playbook, wrote the protein portion of the dietary guidelines. It was extraordinary. 90% of the new guidelines are reflected in the Forever Strong playbook and how to implement it. Why does this matter? Because there’s a way to do it to promote muscle health. Again, how do we make it easy for people? There’s a ton of recipes. More importantly, the recipes are amazing, but it tells you and it teaches you how to visually look at your plate. What’s so important about these guidelines, and this is also something that I think that you will be very much in alignment with me, is that the old guidelines were based on epidemiology.
Old guidelines were based on low-quality data that typically helps create a hypothesis. You can’t base health recommendations on epidemiology. It’s low-quality data. These new guidelines were very transparent. They were based on randomized controlled trials. There was experts in each field, and they showed the literature that was used to inform these decisions. The protein portion of this was based on randomized controlled trials. Much of the work was based on my mentor, Dr. Donald Layman, again, who co-authored the nutrition section of this.
This is based on the data that we’ve known for decades. It’s not just a new thing. If people take this seriously, it will transform their health, I promise you. The new recommendations– There’s a few things that I want to clear up. The RDA, which is the recommended dietary allowance, has not changed. That is still based on the minimum to prevent deficiencies, which is, that’s a whole other conversation, 0.8 grams per kg, probably an irrelevant number.
Ari: Just to be clear, talking about protein now for listeners.
Dr. Lyon: Yes. Those guidelines have not changed. The RDA that’s based on nitrogen balance, arguably, there’s no health outcome that we’ve ever seen based on a nitrogen balance study. That number is probably totally useless, but whatever, it’s a number. The new recommendations recommend 1.2 to 1.6 grams per kg of high-quality protein. That is a tremendous change that’s never been done in the history of the guidelines. This is really, again, it’s going to reorient us to how do we protect muscle and focus on muscle health. It recommends eating whole foods. It’s reduced the grains to two to three servings. It prioritizes whole foods, fruits and vegetables. How do we balance those so that we can prioritize overall muscle health and just overall health?
10% saturated fat hasn’t changed. The reason is, the big thing that changes, instead of getting it from plant-based hydrogenated sources, they recommend it from animal-based sources. The reason that number hasn’t changed is because we don’t have good data either way. Should it be 15%? It used to be 15%. The total diet used to be 15% saturated fat. Now it’s 11%. This recommends 10%, which has really always been the recommendation, but we don’t have any evidence to go higher or lower. We just don’t have enough data.
Ari: I want to flag, this is maybe a digression. I don’t want to spend too much time on saturated fat. It’s interesting that you bring it up because I want to flag this as something that within the diet wars of dietary ideologues, oftentimes people who are advocates of a lower-carb, higher-protein approach will often also be attached to the ideology of saturated fat as being a health food or being very beneficial.
I agree with what you just said about saturated fat. The reality from the body of evidence I’ve seen is that there really isn’t compelling evidence that we should be consuming lots more saturated fat or that it’s perfectly benign to consume lots more saturated fat. That’s an interesting distinction where some people who might be aligned with some of your diet recommendations might be not aligned in terms of saturated fat.
Dr. Lyon: It’s a really good point. Again, I’m neutral. It doesn’t matter to me if someone likes to have a diet that’s high in fat or not, but I would agree with you. I personally am not a very high-fat person. I think that 25% of the population has LDL cholesterol that’s too high, and that’s not that much. If we were to pick a number, 160 milligrams per deciliter, I think it’s 25% of the population. Does saturated fat impact LDL cholesterol and perhaps ApoB? It does. Does it impact it for everybody? Probably not.
Then on the flip side of that, what about carbohydrates? I think some people are very sensitive to fats, and then some people that have, say, triglycerides over 200, those people are sensitive to carbohydrates. I think the future is personalized nutrition and understanding, if we go back to the beginning of our conversation, again, what are your lab values? Those lab values are a representation of how your muscle is managing your diet. If you are someone with LDL cholesterol that is high, that is not genetically driven, then you are someone who has to pay attention to your overall calories, and probably your saturated fat.
If you are someone who has elevated levels of triglycerides, this is probably 25% of the population as well, then you are someone who has to pay attention to your carbohydrate intake.
The Forever Strong Playbook
Ari: Let’s talk more broadly about what your key dietary recommendations are and what you discuss in your new book, the Forever Strong Playbook. How do we actually, from a nutritional perspective, optimize our muscle health?
Dr. Lyon: The first thing is you start your meals by understanding how much protein you need. How much protein do you need in a day? Again, that could be 0.7 to 1 gram per pound of target body weight. Realistically, your plate should be around a third high-quality protein, a third fruits and vegetables, and then a third more starchy carbs if you’re training. When you create a balanced approach, then you get not only the high-quality nutrient-dense proteins which come with B12, zinc, selenium, but you also get fiber and the other phytonutrients.
This is not extreme. I’m not in the camp of all meats and I’m not in the camp of all plants. There’s a very sensible way to eat and to build a life and to build a nutrition plan where you’re not obsessively thinking about it, but you’re being able to actually offload that cognitive load to say, “What does my plate look like and how do I manage that?” The first meal and the last meal are the most important meals from a muscle health perspective because that first meal sets you up for metabolic balance. Meaning if it’s skewed towards too heavily in carbohydrates, then you spike your blood sugar and then you’re chasing blood sugar all day.
If your first meal is prioritized in dietary protein, again, we talk about protein as if it’s one thing, but it’s 20 different amino acids, by hitting the needs of muscle, which is between 30 and 50 grams of high-quality protein, and carbohydrates are controlled, say 30 to 50 grams, then you’re able to balance blood sugar, you’re able to manage triglycerides, you’re able to manage insulin, and you’re able to manage blood glucose. This creates a level of satiety, meaning you’re not hungry, and also a steadiness that really sets you up for success. That’s ultimately what we’re looking for. How do we become stronger, more resilient humans? Frankly, how do we teach our kids to be stronger, more resilient humans?
Ari: This is where we enter territory. I want to applaud you for how balanced and neutral you’ve been in describing this, because this is where we enter this territory of landmines, of all the different people in different dietary camps that you’re going to upset by arguing for one thing over another. You are squarely in the camp that is advocating for higher protein consumption as being very important for muscular health. I know that you also advocate for, don’t let me misrepresent you if I’m wrong, advocate for more animal proteins as being higher quality than plant proteins.
Some of this starts to anger certain people. You’ve also said that you support plant food consumption, which angers the carnivore people, right? Again, lots of landmines here to avoid. I think you’re doing great avoiding them thus far.
Dr. Lyon: Who knows? Already, the reality is-
Ari: Who knows? Who cares? I agree.
Dr. Lyon: The reality is I occupy a very unique space that nobody else does, and that is the following. I have trained extensively professionally in nutritional sciences, and as a physician, and am a physician who is still doing research. I was mentored by one of, I don’t know, maybe there’s four of them, world-leading experts in protein metabolism. He is the guy that did the research. Very early on in my career, I was involved in doing that research with him. For the last– People can have all kinds of emotions and have all kinds of thoughts. Again, at the end of the day, I would say the real emotional part and charge for me is I believe that people deserve to have knowledge, and then they can make their decision.
I’m not invested in whatever their decision is, I’m invested in getting good, solid information out there. I do the best that I can to be as unbiased. I recognize my own personal biases, but people deserve good information and less noise because the window of opportunity, while always there, it closes. Very quickly, the reason I got even into this public space is because I had just finished my geriatric fellowship at WashU. I did a combined fellowship in nutritional sciences and geriatrics. I had spent three months working on end-of-life care where people would fall, break a hip, and they never left the hospital. That was it.
Then my weekends were spent rounding on nursing homes. I opened my phone, I’ll never forget this, and it was like, red meat causes cancer. That’s all BS. None of that’s true. It was all propaganda. I was like, “Oh my God. These people, they’re in their 30s and they can fight about this.” When I have a 74-year-old woman who has now moved to a solely plant-based diet, and she fractured her hip, and her bone density is terrible, and she’s afraid to eat red meat because of something that her doctor said or something that she read, that’s criminal. That’s why I’ve been so outspoken because there’s a responsibility there to do so.
Ari: I have a number of things that could probably be an hour or several hours of discussion-
Dr. Lyon: Sorry about that.
Ari: -in and of themselves. I’m going to list it all off as one question. I’m going to let you address it how you want to address it. We have these ideas floating out there. Like, for example, red meat causes cancer. Like the idea that high protein consumption causes harm to the kidneys. There’s also the arguments about amino acid profiles and plant proteins versus animal proteins. There’s the common position among vegan diet gurus that we’re already massively over-consuming protein, the average person in the United States. Therefore, the idea that we need even more protein is silly.
What else? mTOR and cancer. There’s probably several more in there that I’m forgetting off the top of my head. These are some of the common ideas, common objections to higher protein intake. I know you’ve focused a lot. I’ve seen podcasts where you’ve even been on podcasts with your mentor, and you’ve had extensive discussions on each of these myths. Single out the most important elements from that and give listeners your thoughts on those ideas.
Dr. Lyon: The first one is that protein is bad for the kidneys. Now, this is very outdated. The reason I’m going to bring this up is because I live in Houston, Texas. I was recently on Hello Houston, which is a TV show, radio show there. A nephrologist called in and said people should be concerned about animal protein because it’s bad for the kidneys. Now, that data, nobody talks about that anymore. Immediately, I know that this doctor has not kept up with any of the nutritional data because there’s been multiple randomized control–
There’s meta-analyses, which is a large body of evidence, typically, if it’s done right, high-quality evidence, that does not support it at all. In fact, protein improves glomerular filtration rate, so it improves kidney function. That’s number one. That is just so outdated. When people go on dialysis from type 2 diabetes, I rest assure that it is not from protein. It is from an over-consumption of carbohydrates. It is not from damaging the kidneys with protein. That’s just totally a myth.
The statement that people are already consuming too much protein. The numbers are the following. The average American consumes 1.1 grams per kg. That is more than the minimum. 50% of people are below that, and 50% of people are above that. The average female consumes roughly 70 maybe to 80 grams of protein a day. That’s it. The average male consumes around 90 grams of protein a day. These are the numbers. The idea that we’re already over-consuming protein is not true. The reality is we’re over-consuming calories and we’re over-consuming carbohydrates.
The idea that protein causes cancer or red meat causes cancer, this has never been proven. There’s various kinds of cancers. The idea that it’s linked to this mechanism of mTOR, mTOR is not an initiator of cancer. mTOR is a protein complex that is in the liver and the kidneys and the brain and the muscle. This complex is exquisitely sensitive to amino acids only in muscle. The idea that protein causes cancer because of mTOR would be the same mechanism and the same way of saying exercise causes cancer because of mTOR and muscle, because the mechanism is the same. The input is different, but the mechanism is the same. That’s never been proven.
Protein is bad for the bone, also a myth. Aalso multiple meta-analyses. When I was a fellow, we would look and image people’s hips. We did DXAs. Those that were on a lower protein diet most frequently had lower bone density and were at higher risk for hip fractures. If there’s more, I’m happy to address it.
mTOR
Ari: Let’s go a little deeper in mTOR. What’s the deal with that? Do you feel there is just a broad misconception of the mechanism of mTOR? I do, certainly, that there’s this framing of mTOR as it’s just this bad, evil thing that is driving cancer and aging us and that we need to suppress constantly.
Dr. Lyon: Where I believe this came from is there has been this anti-animal narrative for a long time. They circle around a handful of things to try to prove whatever, why animal products should be considered bad. It goes, bad for the environment, causes cancer. I don’t even know. I’m sure there’s another one. Every six months, it cycles back. The idea of protein and mTOR is actually, it really makes no sense. mTOR is a protein kinase. It was a mammalian target of rapamycin or mechanistic target of rapamycin, depending on when you learned about it. It’s in all cells. It’s in the brain, it’s in the pancreas, and it’s a primary driver for something called muscle protein synthesis. It’s not an initiator for really anything, but it’s a propagator. It allows for the outcome of growth to happen, per se. It doesn’t “initiate”-
Ari: It’s part of the cascade. It’s like spark plugs in an engine. It’s necessary, but it’s not sufficient by itself for the whole thing to work.
Dr. Lyon: There you go. It’s not like a key where you turn it on, and then all of a sudden, you create everything. Let’s say, mTOR in the liver. mTOR in the liver may be much more sensitive to total calorie load or carbohydrate. mTOR, as the central point, has various inputs. It’s energy, it’s hormones, insulin growth hormone, it’s resistance training, it’s exercise. There’s four main pathways, four main inputs, especially in muscle. For whatever reason, people would say, well, protein must be bad because it stimulates mTOR. Therefore, if you’re afraid of cancer, then you shouldn’t want to stimulate this.
That just doesn’t make sense from any perspective, from a mechanistic perspective, because muscle is very unique in the way that it’s much more sensitive to amino acids, so resistance training and amino acids. This mechanical motion and amino acids, which then would stimulate mTOR. If you were to believe that amino acids were bad, if amino acids were bad for muscle, then you would have to also believe that resistance training would also cause cancer. It just doesn’t make any sense. It’s been this perpetuation of, again, I think more of an anti-animal narrative because the reality is mTOR is much more sensitive to, say, overall calories and carbohydrates in all the other tissues. That would be much more detrimental.
One more thing is that mTOR, as you age, it has this lower-level hum. It’s not suppressed. It’s actually a little bit more ramped up as you age.
Ari: The presumption from a lot of these narratives that links mTOR with these bad outcomes is also that there’s a linear curve, that it’s a direct correlation with mortality, meaning the higher mTOR is, the higher risk of mortality, cancer, and dying. The lower it is, the better. That’s the implicit assumption in a lot of that framing. I would encourage people to just do a simple Google image search for mTOR and mortality because it’s a U-curve. Both high and low mTOR levels are associated with high mortality.
Dr. Lyon: One more thing to that is it’s really dangerous to take a mechanism and then say, well, these are the outcomes. As we talked about earlier, the body clearly doesn’t work that way. There’s not just one input. It’s a very complex system. Clearly, resistance training is not bad. Clearly, dietary protein is not bad. We’re not over-consuming it. If you want to really talk about mortality, the way you live long is you must have strong skeletal muscle. Period. The risk of mortality is higher if you are frail. The risk of dying from all-cause mortality is higher if you have low muscle mass.
The way in which we protect muscle, there’s really two main ways. It’s through resistance training. Also, you need these essential amino acids. You do not make them. You must ingest them. Could you get them through plants? You totally could. Could you eat enough plant-based products to get the amino acids you need? Yes, you can. There’s two caveats to that. It’s not just the protein. It’s also the micronutrients, the food matrix, like B12, zinc, selenium, these other components that are critical for healthy aging. It’s not to say that you can’t take a supplement to improve that. You could, but you just have to be very careful about also managing your carbohydrates. You just have to be very aware with the decisions that you’re making for overall, long-term health.
Anabolic resistance in aging
Ari: Okay. I have a couple more things, and then we’re going to wrap up. One is anabolic resistance in aging. Can you tell people a bit about that?
Dr. Lyon: Yes. I will say in the playbook, I highlighted something for the first time that we haven’t published yet. This is making protein decisions. This is this U-shaped curve. I know it’s hard to see, but I’m going to explain this. The idea of anabolic resistance is that the body is less efficient at sensing these amino acids. Anabolic resistance is, if you think about anabolism, this is growth. Catabolism is breakdown, anabolism is building up.
What can happen as you age is that the ability to build, rebuild, and repair decreases. Your body turns over four times a year the efficiency of utilization. Think about it. When individuals get older, maybe they get more wrinkles. Obviously, wrinkles is not just due to decreased turnover, but maybe you have impaired wound healing, or maybe you notice that your hair is a little bit more brittle. There’s a whole host of things that can happen. Anabolic resistance is a “normal process of aging,” but it can be overcome, meaning you can make your muscle respond like youthful muscle just by a series of decisions.
This is, again, in the playbook. This is the first time it’s published, and it’s how do we make protein decisions? This might shock people, but the older you are, the more protein you need. The more sedentary,– First decision is age, second is physical activity. The more sedentary you are, the more protein you need, which is very counterintuitive to people because if you are not stimulating that muscle through resistance training, you must stimulate it through diet.
Metabolic health is the next decision that you make if you are metabolically healthy, meaning metabolic syndrome, which is really unhealthy muscle. If you have metabolic syndrome or you’re more metabolically unhealthy, you should prioritize protein over carbs. Then the last thing is personal choice. There’s a million different ways to do a nutrition plan right, but it’s a U-shaped curve. There’s this middle ground. The more athletic you are, say someone like me who is, I don’t know, I train four days a week, I can probably get away with a little less protein. Then as you move into a more elite level of training, you also need more, closer to that one gram per pound of target body weight.
There is this U-shaped curve of protein intake, and it relates to anabolic resistance because, again, more total protein at once improves efficiency. It improves the way in which your muscle recognizes these amino acids.
Ari: I want to get your quick thoughts. This is a challenge because these are not quick topics, but three things. One is rapamycin, which is literally mTOR is named after this compound, and your thoughts on that. GLP-1s, which is something that’s new on the scene, relatively new on the scene since our last conversation a few years ago, and hormone replacement therapy in women post-menopause, and how these three impact the muscle-centric equation.
Dr. Lyon: Rapamycin is an mTOR inhibitor. I’m not a huge fan of it. I haven’t seen a lot of human data. I still have a medical practice. We don’t use it in our medical practice. I have a medical practice. I see patients every week. Again, there’s a lot of discussion around it. I haven’t seen enough clinical data that I feel comfortable because, again, we know what muscle does. I don’t want anything to impair that. It’s not worth it.
Ari: I agree.
Dr. Lyon: Number two, GLP-1s. We do use those in our clinic, and we have been using them for years. GLP-1s are here to stay. They’re the most effective weight loss tool. I used to run a weight management clinic in my fellowship. I’ve never seen anything more effective. However, this conversation of when the obesity epidemic hit, everybody ignored muscle because movement hadn’t really changed. It was still at a lower-level hum. We missed that. We are just about doing that again. We’re going to trade “the obvious obesity epidemic for an epidemic of sarcopenia.” This is what I-
Ari: Explain why, more clearly, people might not understand the link between those.
Dr. Lyon: What is going to happen is, again, these GLP-1s are amazing. We use them all the time. It allows for an individual to lose body weight at rates that we’ve never seen. Depending on the length of time and the dose of the medication, they might lose 15% to 24% of their body weight. 50% of that could be muscle. What happens is the average individual stays on these medications for two years, so they accelerate the loss of muscle mass loss. If sarcopenia is 3% to 8% per decade, and you go on one of these medications, you condense that amount of muscle mass loss in a very discrete time frame. You go on these medications, and you come back off of them, and you go on them again. You now are a smaller version of yourself with more body fat and less muscle.
Muscle is what determines your blood sugar regulation, your triglycerides, your insulin, all the metabolic engine components to protect against Alzheimer’s, cardiovascular disease, type 2 diabetes. Muscle is your armor. If you take that away, you’re now left in a worse position than you were when you started these medications. My concern is that we’re going to create this sarcopenic obesity landscape, which is going to increase osteoporosis and increase frailty at much younger rates, so we’re going to be much younger. I think it’s going to be devastating.
Through good training programs, which again, I have protocols in my book specifically for this, and good nutritional interventions, this can be prevented. It’s a non-negotiable. You have to do this. Otherwise, there’s data that supports that the loss of muscle mass is much more detrimental to aging than the gain of body fat.
Ari: Real quick, I think there was a recent study, meta-analysis, that found very high rates of rapid weight regain following GLP-1s, suggestive of basically once you go on this and lose weight this way, it becomes necessary to stay on them for life at that point. Obviously, there’s a gray area here, but what are your thoughts on that idea?
Dr. Lyon: We take people off them all the time. We put them on very low doses to help with metabolism and help with inflammation. Actually, I think we’re going to start to see data that improves muscle quality. We’re going to see data that it helps reduce that intermuscular adipose tissue. I think that they can be very beneficial, but you have to use them with a provider that you trust. That’s very important. Again, it’s a great tool and it can be used.
Then you throw in hormone replacement therapy, which again, we offer in our clinic. I do research in this. My husband, who you know is a former Navy guy, is actually in his third year of urology residency. He studies androgens and andrology and men and women’s health specifically related to hormones. We see that when hormone replacement therapy is used in conjunction with these GLP-1s that there’s a very good balance that we see. Again, I think hormone replacement therapy is very safe. I’m just so happy that it’s getting a resurgence and a re-examination of the data, which is definitely necessary.
Ari: Dr. Lyon, last thing is tell us about this new book. Your original book was Forever Strong. This is the Forever Strong Playbook. What’s in it? Why should people get it? Give us the whole pitch for your new book, which is coming out– did it just come out 28th?
Dr. Lyon: Comes out tomorrow.
Ari: Tomorrow, okay.
Dr. Lyon: By the way, [crosstalk]
Ari: We’re recording this on the 26th, so it comes out January 27th.
Dr. Lyon: Yes. Also, what a great friend are you that you are like, “Let me help you.” I really appreciate this because this book, I think, can change a lot of lives. It’s the book I originally wanted to write. It’s evidence-based, and it covers the pillar. It actually covers how to think because there’s a gap between being interested and educated and actually taking action, and this will address that. The first pillar is How to Think, and then, of course, How to Eat, How to Move, and How to Recover, which in the How to Recover, it has cold protocols, heat protocols, red light protocols. It has all the protocols that we use in clinical practice, but it’s a tactical field manual.
You don’t have to know all the science. I don’t care if you’re a beginner or advanced. This book is laid out in a way where it brings the best of evidence to life. In fact, we’re going to be doing, which, actually, I think that you should come on, and I think that you should talk about, red light. We are going to put this book into life February 15th. I think it’s the 15th. We’re going to do this book together for six weeks, and it’s going to cover all of the How to Eat, How to Think, How to Move, How to Recover, but it’s a tactical field manual. It’ll teach you how to implement these new guidelines, and I promise you that if you’ve struggled before, this book will give you a science-based plan to build stronger, more resilient humans.
Ari: Beautiful. I want to give my thoughts on it as well, which are I’ve had a chance to look at the e-copy, I don’t have a physical copy. I would like to show it up here on screen. I have ordered them at this point, and they’re going to hopefully arrive tomorrow or the next day. I’ve ordered a dozen copies for all my friends and families that I want to give this to because I just love the way you’ve broke down this whole science of why muscle is so important and just a very simple practical plan of how to build it, how to maintain optimal muscle health. It’s very straightforward. It’s very practical. It’s not overly complex, and it’s also deeply scientific, which I love as well. I’ve got a whole bunch of copies arriving to me to give to my parents who are 80-ish now and lots of friends and family members. I’m super excited for this. I think everybody should go out and get it. Tell people where they should get it. Do you want to direct them to Amazon, Barnes & Noble, your site? What’s the plan?
Dr. Lyon: You can go to drgabriellelyon.com/playbook, and it has Amazon, it has Barnes & Noble, it has all the retailers. There’s a bunch of bonuses that I’m hoping will still be up when this comes out. Again, anywhere books are sold, and you will love this, I promise you. This was the book that I had originally wanted to write. Ari will tell you I don’t do anything marginal. It’s [inaudible 01:09:22] my time and attention to it. It is full force. Again, there’s a lot of value in here.
Ari: 100% agree. Dr. Lyon, always a pleasure. Thank you so much for coming on the show. I know you’re traveling all over the place doing podcasts, going on TV, trying to bring as much promotion to this book as possible. Thank you for coming on the show again. It’s really always a pleasure.
Dr. Lyon: Thank you so much for having me.
Links
00:00 – Intro 00:29 – Guest intro
04:36 – Why skeletal muscle is worth paying attention to
11:45 – Sarcopenia
16:34 – The connection between lipids and muscle tissue
25:22 – Myokines
33:25 -The new US dietary guidelines
41:18 – The Forever Strong Playbook
52:05 – mTOR
57:45 – Anabolic resistance in aging
