Are you frustrated by the constant struggle to shed those extra pounds, all while being bombarded with claims about your “slow metabolism”? It’s time to cut through the noise and get to the real facts.
In today’s episode Ted is going to interview Eric Trexler, a seasoned fitness enthusiast, coach, and a pro natural bodybuilder with over a decade of experience in the field. What sets Eric apart is his commitment to providing evidence-based insights in the ever-evolving world of fitness and nutrition.
During this conversation, Ted delves deep into the world of metabolism with Eric. They shatter common myths and misconceptions surrounding metabolism and its impact on weight loss. Eric’s unique perspective sheds light on the importance of evidence-based decision-making in the fitness journey.
He also shares the practical strategies to overcome challenges related to appetite and cravings and explores the concept of energy balance and how meticulously tracking calorie intake and expenditure can lead to successful outcomes.
So, if you’re ready to debunk myths, enhance your knowledge, and uncover evidence-based strategies for your fitness journey, you won’t want to miss this interview with Eric Trexler. Listen now!
Dr. Eric Trexler
Dr. Eric Trexler is a professional body builder, a sports nutrition researcher, the co-owner of Stronger By Science, MASS Research Review, and the MacroFactor nutrition app, as well as the co-host of the Stronger By Science podcast. He received his PhD in Human Movement Science from the medical school at the University of North Carolina, and now he does metabolism research at Duke University.
Connect to Dr. Eric Trexler:
- The truth behind common metabolism myths and how age affects metabolic rate
- How appetite regulation is influenced by hormones and neurophysiological responses
- Strategies to navigate challenges related to cravings and hunger
- The role of energy balance in achieving sustainable weight loss or muscle gain
- Practical methods to fine-tune your fitness goals and make evidence-based decisions
- The concept of energy balance and why tracking calorie intake and expenditure can lead to successful outcomes
- And much more…
Podcast Transcription: Metabolism Unveiled: Debunking Myths And Revealing Evidence-Based Strategies For Sustainable Weight Loss with Eric Trexler
Ted Ryce: Dr. Eric, thanks for coming on the show. Excited to have you. Thanks.
Eric Trexler: For having me. I'm excited to be here.
Ted Ryce: Yeah. We connected because I heard you on a friend of mine's podcast, Danny Lennon, and you were talking about some of these newer research studies on metabolism. And it's such a hot topic, man.
Everybody still talks about, no, I think I have a slow metabolism, or maybe my hormones are kind of slowing me down. So, I'm really excited to get into that and, you know wherever this conversation takes us.
Eric Trexler: Yeah, that sounds great.
Ted Ryce: And just so, people who might not have heard of you before, just talk a little bit about who you are, what you do.
Eric Trexler: Yeah, so I am a fitness enthusiast. Been into it since I was 12 years old. Been coaching for like 14 or 15 years, I think. Pro natural bodybuilder. Uh, got my PhD in human movement science and now I do metabolism research at Duke University. Uh, and I also publish the mass research review every month where I stay up to date with all the new research on fitness and nutrition and metabolism, which I, I'm sure we'll dig into here.
Ted Ryce: Yeah, absolutely. And I'm a big fan of your review, and I'll just say this, I'll just come out and say it. If you are listening to this podcast and you are reading information on blogs about what to do for your health, specifically with body transformation, fat loss, muscle growth, those types of topics, what I want to suggest to you is that you consider getting something like Eric's mass review because if you, I mean, just the level of information and what you learn from something like the review is so next level, if you're reading blog posts from influencers, you're wasting your time.
So I'll just come out and say it like that. Do you have anything to say about what I just said?
Eric Trexler: No, I think, you know, I want to give the bloggers out there some credit. It's always nice to be exposed to different ideas, but I think ultimately, as you kind of advance in your fitness journey, you run into a scenario where your three different, you know, your three favorite bloggers have three different opinions about a new piece of research or a particular concept in nutrition or training.
And then, what do you do from there? Right? So if you trust the opinion of three different people and they all disagree, you kind of want to say, well, can I trust someone to just kind of dive into the research and do that work for me? And kind of figure out who, of these three people who seems to be on the right track, or maybe none of them, right?
So, for us, you know, what we try to do is see what people are chatting about in the fitness space. Then give a really thorough evidence-based take on some of these new topics in the area.
So, I think there's, you know, depending on where you are in your fitness journey, it's great to kind of find people who know things, read their blogs, watch their YouTube videos, but you probably will reach a point where you say, okay.
Now we're in, you know, conflicting opinion land and we probably need to get to the science. And all of the mass reviewers are scientists. You know, um, we, we all do research. We're all active researchers in the field and, and we review studies that are very much within our domain of expertise.
Ted Ryce: I appreciate that perspective that you're sharing. And when I hear that and when I think of you, one of the things that I like to do on this show, Eric, is typically you'd be on a show like Danny's. I love Danny's show. It's the best podcast on nutrition. Hands down if you really want to dive into the science behind and, and the people who are actually conducting it like yourself.
You were a guest on there and Kevin Hall was a guest on there. My audience though, they're learning from Bean Greenfield as an example, and or, or I tried to mess up his name to kind of protect it, but I kind of screwed up there.
But other influencers who are really, and, and actually I'll just say his name, Ben who Ben Greenfield tried to make a joke, didn't work out so well, but there's people like Ben, there's people, like I've had Dave Asprey on the show back in the day, been doing this show for like nine years, had him on twice.
And at the time I wasn't really, I didn't have the chops to figure out, is this guy for real? Are the mycotoxins a thing? Does fasting and drinking coffee with butter in it is that the magic thing that I need to do to lose fat? And then I kind of got disillusioned with the space. That's where I found guys like you, Alan Aragon, Lane became friends with Danny, hung out with him in Chiang Mai, in Thailand, got him to try durian.
Uh, if you know what that is, the most infamous fruit. And so that's why I love talking to people like yourself, Eric. Because I feel like there's a, I feel like at least I'm doing my part to bridge the gap between the people who are trying to sell things where. Maybe there's something there, or maybe it's just complete hype, but what are the things that we know for sure that someone listening right now can listen to and go implement and get results regardless of the, you know, of the anecdotal story around how good it was for that health influencer.
Eric Trexler: Right? Yeah. I mean, like what are the kind of basic take-homes that, that people can really hang their hat on? Is that the question? Well, I
Ted Ryce: Was just making a statement, but what I'd love to dive into you with is, um, is metabolism. Because it's something we've talked about on the show. So what are, you know, all the, you, you're on social media like I am.
What are the misconceptions around metabolism, especially for people who are 40 plus and looking to get in shape and maybe have heard this narrative that maybe it's the metabolism and you need to reboot your metabolism. What do they need to know?
Eric Trexler: Yeah, I think the biggest myths that are out there, you know, a lot of people believe that as they age, a kind of physiological decline in metabolic rate makes it harder to pursue fitness goals.
And in reality, you know, the most up-to-date research using the best methods available would indicate throughout most of adulthood you know, your basal resting energy expenditure stays pretty stable, you know, into the fifth and sixth decade of life. And, and, you know, eventually there is a bit of a decline largely related to just the loss of muscle mass that occurs, you know, in the sixth, seventh, eighth, ninth decade of life.
But, you know, for most people, well into their fifties and sixties, basal metabolic rate is not really dropping off that much. Another major myth in my opinion, is that resting metabolic rate is going to be highly predictive of your success if you're trying to lose weight or lose fat.
When we look at research studies, we don't really see that the people with the highest baseline resting metabolic rate, the people who would say, "I have a fast metabolism." Those individuals don't necessarily seem to be leaner if we just kind of, you know, do a cross-sectional look at the population.
The leaner folks, the lighter folks do not systematically have faster metabolic rates. And when we do a weight loss study, we do not find that the people with faster metabolisms at baseline have more success during that intervention.
And then I think another element that people really get focused on. You know, people talk about metabolic adaptation which loosely we'll define as when you're doing a weight loss phase eventually, it's very common to see that your total daily energy expenditure, the total number of calories you burn each day, is going to go down a little bit for a variety of reasons.
A lot of folks will run into a little bit of friction during that weight loss phase and think that they've run into a brick wall. In reality, that little bit of friction can definitely be overcome by manipulating physical activity and energy intake. And that probably leads me to the final big myth that's worth noting.
And I work in Herman Pontzer’s Lab, that's where I do my research. And, and he wrote the book "Burn." I think his book does a really excellent job kind of demonstrating and popularizing the idea that a lot of people, I, I, I think that a lot of people really overestimate the degree to which doing a bunch of exercise is going to cause tremendous amounts of fat loss.
Now, exercise is fantastic for a lot of different reasons. It should be part of your health and fitness plan. It should be part of your body composition plan if, if you're trying to improve your body composition. But sometimes people think, well, I'll, you know, do a walk in the afternoon and, and that's going to really get things moving.
They run into some friction and they say, you know, this damn metabolism of mine. And in reality, resting metabolic rate, the degree to which metabolic rate changes throughout a diet, these things are not really going to be, make or break factors in your success. It is true. When some people do a diet, they experience more metabolic adaptation than others.
They have a bigger reduction in their daily energy expenditure. And yeah, that can make it take a little bit longer to get where you're trying to go, you know? Um, it, it can kind of make you tack a few extra weeks onto that diet to get to the destination. But ultimately these things are not insurmountable and, and usually in places where people throw up their hands and say, "My metabolism betrayed me."
It looks like we're at a dead end. In reality, those are scenarios where you do a little bit of troubleshooting, you figure out what's causing the plateau, you pull a few levers, and then you keep on going.
Ted Ryce: Yeah, Eric, so many things here. So first of all, your resting metabolic rate, the amount of calories you burn at rest, which is around 70% of your, that doesn't change up until maybe your seventh decade.
The other thing that you said is that, um, the other thing that I think is really important to dive into is that, um, with metabolic adaptation, what we're talking about, I think I've talked about this a little bit, but I think it's such a tricky concept if you're not a scientist like yourself. It took me a while to, to wrap my head around it.
So if you're listening right now, if you lose, if you're 200 pounds and then you lose 30 pounds and you're now 170, you're going to burn less energy because your body's smaller. And what Eric was talking about is beyond that, there's something that's called metabolic adaptation.
And Eric, can you just talk about that? Because there's this slowing down of metabolism that's normal. For example, a truck burns more at idle than a sedan, generally speaking, right? So you're burning less energy. But there's also this thing called metabolic adaptation. Can you talk about that and um, and where it comes from? Like what's causing this slowdown?
Eric Trexler: Absolutely. Yeah. So the main thing that's causing metabolic adaptation, so what we're talking about here is the adaptive reduction in energy expenditure beyond what we would expect from just being a smaller person. And what's really driving that mostly seems to be a hormone called leptin, which I believe was discovered in the 1990s.
And it is a, a hormone that is largely produced by our fat cells and when they are full of energy, when our fat cells are big and you know, we have some extra body fat. Our body's making plenty of leptin, circulating levels are high, and the hypothalamus in our brain can detect that and says, oh, great, we've got plenty of energy. No big deal.
And the hypothalamus is a key center of the brain that integrates a lot of information about how much we're moving, how much we should be moving, how much we're consuming in terms of energy intake, and how much we ought to be consuming. And so as we start to lose fat, our fat cells shrink. They contain less energy than they used to, and they produce less leptin than they used to.
The hypothalamus senses that and says, well, that's not great. You know, it's kind of like when you're checking your bank account, you expected the number to be much higher and you say, oh, we need to do some conservation strategies to make sure we don't hit zero here or go below zero.
Ted Ryce: Story of my twenties.
Eric Trexler: Right. Yeah. So, it basically, the hypothalamus sees this dropping leptin level and says, well, this is a bit of a, a biological, physiological threat. I mean, the department I do research in is actually the Department of Evolutionary Anthropology. So, you know, we like to look at these types of things from the perspective of evolution and of course, as an organism that for the vast majority of our evolutionary history did not have access to supermarkets, we needed to be responsive to changes in the amount of energy available in our immediate environment. And when energy's low, we need to be first of all, we need to impetus to go get more energy. So that's where hunger comes into play when we're dieting.
But we also, you know, it would be advantageous to have some mechanisms in place where we can conserve energy. So, a good analogy that most people can, can really identify with is just the low battery mode on your phone, right? So once your battery gets below a certain point, then it says, Hey, I'm going to kinda shut down some of these non-essential functions and I'll still keep working, but you know, we're going to power down some of the stuff that just wastes energy for the battery.
And so that's what we're seeing really is, you know, when, when we're experiencing a lot of metabolic adaptation, when we're dieting, resting metabolic rate is going to go down a little bit just because we weigh less and because we're in a caloric deficit. But metabolic adaptation has a, a really big impact on non-exercise activity thermogenesis.
That refers to the calories that we burn just in our kind of normal day-to-day movement and activity. And so, in some examples you might see that someone is simply less likely to, you know, if. One of the examples I use is you walk past your mailbox, you forget, oh, I need to check the mail. If, if you're deep in a diet, maybe you're making the conscious decision.
I don't think I'm going to go back there. Right? But there's even subconscious things, things that you're not in volitional control of, like fidgeting in a chair. I. You know, bouncing your leg up and down as you're sitting. And we will even in kind of more extreme scenarios, see changes in postural regulation.
Uh, so when I was preparing for a bodybuilding competition, my coworkers pointed this out. I didn't even recognize it myself, but I was just like melted on my desk most of the time instead of sitting up straight. 'Cause you're using muscular energy to maintain that upright posture. And, and so that is kind of what we're talking about with metabolic adaptation, and it's these little mechanisms that, you know, on the energy side, energy expenditure are trying to conserve energy and make sure we're not wasting it.
Then of course, the effect that a lot of dieters know on the other end of the equation, which this is kind of separate from metabolic adaptation, but...This whole integrated process of responses obviously includes increased hunger, increased drive to eat, which is actually kind of different than hunger.
So we're not just physiologically hungry, but we're also a little bit more fixated on food. We think about it more. Um, so kind of desire to eat goes up. But the one thing I always like to highlight when I talk about metabolic adaptation, and when I say always, I mean, now, you know, I've been talking about this concept.
My first, the first time I really dug into it was 2013. But as my understanding of it evolves and as more research comes out, one thing I really like to highlight lately is, you know, imagine, going back to the phone analogy. Okay. It drains down, I think for me at 20%. That's where it goes to low battery mode.
Okay? So then my, my battery goes to 19% and it says, Hey, you're on low battery mode. I do not then say, oh, great, I. My phone will never die. 'Cause it's on low battery mode, right? It's still going to die. I mean, it's still draining. It's just draining at a slower rate, and that is an important thing to keep in mind for dieters.
A lot of people run into a little bit of friction. They can tell based on their rate of weight loss and their energy intake. “It seems like my metabolic rate has slowed down a little bit. It seems like I'm having some metabolic adaptation.” Sometimes people misinterpret that as saying, because I'm plateaued with my weight loss, this is it. Like we're at a brick wall and if I try to go further, my body's going to fight me even more in like a one-to-one relationship and I cannot lose more weight. That's not the case, right? So what it tells us is that we need to get a little bit more creative.
We need to maybe make some adjustments to continue making progress, but. You know, I think when people use the term "starvation mode," on one hand, that is a fairly representative term, you know? So, I don't kind of dismiss it like, you know, right away.
I mean, it is a representative term of what's going on, because like I said, getting back to that evolutionary perspective, it is a starvation prevention mechanism or set of mechanisms. So, I understand that. However, I think sometimes that people get that idea that, you know, it's this starvation mode, it kind of gives it this idea that it's insurmountable. You know, that this is it. And if, if I try to push further, that's somehow a bad thing.
'Cause you know, I should not be pushing into something with such a negative name as starvation mode. You know, you don't want to, what's level two of starvation mode? It doesn't sound like a good thing. In reality, what we're talking about here is just some energy conservation mechanisms which is limiting our caloric deficit.
So, we just need to find ways that are tolerable and sustainable that can rediscover that, that caloric deficit or, you know, or grow that deficit to a point where it's going to actually be compatible with the rate of weight loss we wish to achieve.
Ted Ryce: Yeah. Expertly stated, and I love how you talked about starvation mode as, as being a real thing, because that's what it is.
Eric, correct me if I'm wrong here, but even if someone was, let's say overweight or obese and they were deserted on a desert island and they were starving to death, they probably wouldn't get super-duper lean and lose all their body fat and then start to lose muscle. They would lose the muscle mass.
They would lose the organ, like their hearts might lose muscle, their other organs might lose muscle, and they would probably die still, maybe overweight. Um, they wouldn't preferentially lose body fat. And the reason I'm bringing that up, and, and I would love to hear your, your answer about that. Of course, there's no studies, right?
Uh, starving or, or maybe there are, but I don't think so. People who've started starved to death, what did they lose first? But just so that people understand. It's a mechanism that kicks in to drive up your hunger because of the immediate perceived threat. And that it's also important because, well, it's, it's going to get into a conversation about what you talked about, the what are the methods we can use for dealing with that hunger psychologically and physiologically, and getting back to a place where you, you find that sweet spot.
Where you feel good and also you're losing weight. But can you just talk about that for a second? The idea that, you know, someone who is maybe overweight or obese, if they, they did starve to death, they, they wouldn't necessarily be lean at the end, would they?
Eric Trexler: Well, it kind of depends, you know? 'Cause with starving to death, um, you know, there, there we're talking, I did not think we were going to come here with starving to death.
You know, I think the question, you know, we all die of something, but we die of a specific thing, right? So, starving to death usually is like, of the variety of nutrient shortcomings one could encounter, what is the one that became lethal first? Right. And so yeah, like in, in an actual scenario of truly starving to death with no medical intervention, you would, you would die by the time you know that you had a shortfall, that that reached a lethal level of, you know, some essential nutrient in the diet. You know, you know.
Because that's why we have to eat, right? I mean, you, you, you can't say like, well if we all just stopped eating, then we would get down to 0% body fat and then die from a lack of fat.
I mean, we would die from a, a much more critical nutrient deficiency long before we got there. Uh, in that scenario...
Ted Ryce: For example, protein or...
Eric Trexler: Yeah. Yeah. I mean, if we're not consuming any of our essential vitamins, essential fatty acids, essential amino acids, I mean, yeah. We'll, we'll die. I mean, it's, I mean, even, you know, People, you know, would encounter scurvy, you know back, you know, before, um, the first randomized controlled trial or the first I think that, I think that's what they attribute to as the first randomized trial.
But before sailors found out that you could eat citrus fruits to, to keep scurvy at bay, I mean, people died because they had nutrient deficiencies and. They didn't get down to 0% body fat. It was a specific nutrient deficiency. One thing that is interesting is there actually is a pretty fascinating case report of someone who basically did a medically supervised starvation protocol.
They, this was a long time ago. Um, but they had a lot of excess weight and they, they wanted to get down to, um, you know, a much lower body weight. Uh, and they didn't want to waste any time. So they did a medically supervised fast for, I mean, I think it was a year, give or take. I forget exactly how it was over 300 days.
Ted Ryce: of zero calories.
Eric Trexler: Uh, yeah, I mean, it was, well, it was basically they, they had the smallest amount of nutrient provision that could keep a person alive. So, I think that they had a vitamin supplement. I think that they had an electrolyte supplement. I think they had some essential amino acids, which would have, you know, a fairly negligible amount of calories relative to a typical human diet.
But, we're talking as close to, and I think they might've had an essential fatty acid supplement as well, but basically, they starved except for just the minimal provision of nutrients that would keep a human body alive. And usually what we'll see, even in an extreme scenario like that, it's a matter of magnitudes, right?
So, you know what? Just about any weight loss trial, even people who are relatively sedentary, untrained, not particularly muscular, have a lot of excess body fat. They will lose a combination of fat mass and fat-free mass as they go. Now, usually, you know, at the beginning, it's not a lot of true muscle loss.
'Cause fat-free mass is everything that's not fat, you know, it includes
Ted Ryce: water, bone
Eric Trexler: water, organ, tissue, glycogen. Yeah. Hopefully, we're not losing too much bone. That would be a very bad weight loss intervention. Um, you know, we might see a little bit, but yeah, so it's, it's everything, right? And so, we do expect that a decent chunk of weight loss is going to be non-fat tissue.
Usually, we don't see, but it it, like I said, it, it's a question of magnitudes. Usually, we will see kind of the steady decline where some of it is fat-free mass. Some of it's fat mass. Usually, the leaner you get, the higher proportion of fat-free mass that that's being lost. So, you know, then as you start getting very, very lean, we see an even greater proportion that's coming from fat-free mass.
So, it's not just like a linear kind of thing. It's. You know there's a paper from 1986 by Forbes where they look at the relationship of how much body fat do you have, and therefore what proportion of the weight you lose will be lean versus fat mass.
And it does change based on your body fat, but your main point holds, and I think there are two, two factors, which, yeah, I mean, starvation like I said, you know, we'll, we'll die of something before we get to 0% body fat in true starvation, but more pertinent to a weight loss endeavor. We have to think about these mechanisms, these responses to dieting, and two very different timescales. There's a long-term timescale.
We see something like metabolic adaptation, but there's also the short-term timescale where it's the kind of day-to-day feeling sluggish being in a deficit reduces your resting metabolic rate active. You know, just being on a deficit for a few days willreduce that. There's studies where they'll just say fast for one day and we'll watch the drop in, you know, in resting metabolic rates.
So, there's these kind of short-term regulators of energy expenditure and hunger and all these other responses. And then there's these longer-term regulators as well, and we need to keep both of those times scales in mind as we go
Ted Ryce: Thanks for indulging my question there, and I want to just share where it came from.
Someone was arguing with me on Twitter as what happens on Twitter? They were saying this and, and I forget the exact context, but it made me wonder, um, and I know you would be someone who I could ask about that, who at least if you didn't have to answer like you did today, at least point me in the right direction.
And the other thing is this, with this narrative around starvation, we don't know each other that well, Eric, but I've lived in Southeast Asia for a few years and I've seen people who are, you know, in Cambodia in particular, you know, were they starving to death? I don't know if that was the case, but they certainly did not have a lot to eat.
And there's this belief, I want to have this conversation. And I've even showed photos sometimes when people were like, listen, you know, starvation mode? I'm like, Google starvation and click on images. That's what it looks like. And we have this very strange narrative going on and beliefs around dieting and what it means and what the causes of, and it's usually metabolism or hormones or toxins in the environment.
And it's such a tough concept in part because of all the health influencing, if you want to call it that - misinformation is what it actually is - but for people to really understand what's going on and, and then we come up with these extremes and it's just, I, I'm hoping conversations like this start to shift people's mindsets out of the marketing lingo and back into like, Hey, well, this is what happens when you starve to death.
And so that's why I asked that. And I would love to shift the conversation though, because you said something earlier where you mentioned that, okay, we've looked at people's metabolisms and having a slightly faster metabolism. And as you mentioned, just for the people listening, it's not that you necessarily have something special going on.
Either you have a bigger body, which increases your metabolic rate because a bigger body needs more energy to maintain its size. Or like what you mentioned, Eric, in the, the movement involved, the non-exercise activity, thermogenesis, keeping your posture, fidgeting, talking with your hands if you're in, if you're emotionally expressive.
So, you mentioned that that didn't matter as much. That wasn't the key thing when showing, okay, who's successful who or and who isn't. So that leads to the question, what are the game-changing characteristics, strategies, et cetera, that leads to success for people trying to achieve better body weights?
Eric Trexler: Yeah, that's a good question. I mean, there's still a lot that we need to figure out. In that regard. But we can at least, you know, success leaves clues and we can look at trials and say, okay, what characteristics or behaviors seem to at least correlate with higher success rates? And we're not talking about just in a weight loss phase, so 12 weeks or whatever.
But you know, two years after a weight loss study who has kept the weight off. A couple of things seem to always kind of come up. One is just continuing to do self-monitoring behaviors, so things like continuing to track your body weight as long as it's not something that causes, um, excessive psychological distress.
Same thing with tracking food intake in some way, right? So, a lot of people say, well, I'm not going to track my food intake 'cause I don't want to weigh every single thing I eat and, you know, put it all in a big diary or an app or whatever. If you want to do it that way, you can, it's a successful way to do it.
But there's other ways to keep tabs on your eating habits. Right? You know, it could be as simple as, How many times a week did I have a second serving when I intended to have one? Or how many days a week should I be having desserts with, with my dinner? Or am I getting at least three servings of vegetables?
There's a million ways to track your diet and some of them are, are much more feasible or less, less time-consuming, less effortful compared to others. So self-monitoring behaviors, and some of it's just as easy as. I'll be honest, one that I use that is extremely vague and some people might use this without knowing it's a self-monitoring behavior.
But when my pants start to get a little tight, I say Uh-oh, you know, I can tell that, you know, the size and shape of my body is changing and maybe it's time to intervene because you know, I don't want to buy new pants and this is an indicator. Oh, okay. Things are getting away a little bit. Let's kind of tighten things up. So, self-monitoring is big.
Another thing that seems to correlate with success is just maintaining a high level of physical activity, and that may sound contradictory relative to something I said previously. So, what we know based on the trials is that if we just tell someone, "Hey, go. Do you know? A hundred extra calories a day of exercise."
The weight loss that we see from that is going to be modest. It's not even going to be what we would mathematically predict from a 700 calorie per week deficit. You know, there, there are a lot of factors that make exercise as a standalone intervention pretty underwhelming, as a weight loss tool. However, staying engaged in exercise seems to just kind of keep people engaged with their weight loss or weight maintenance process.
It kind of reaffirms that commitment to the whole set of behaviors that they've committed to changing. Um, of course, it does have some impact on weight loss. Um, you know, and, and so, It's this kind of mixture of staying engaged with that fitness journey, staying engaged with the weight loss journey having some positive impact on the energy balance equation by burning some extra calories each day.
And also, physical activity seems to be related to appetite regulation. Um, and, and so what we find is there's a very non-linear relationship by which physical activity can impact. Our, our drive to eat and our appetite. And for people who were formerly quite sedentary, a lot of times maintaining some physical activity will actually facilitate appetite regulation to some extent.
Ted Ryce: Let's talk about that because it's something that I learned. I don't know if you know Eric Williamson from Unlocked Fitness. He's a fan of yours and he was someone who I coached with, but Eric taught me that and it's something that I teach my coaching clients. And it's always a game changer because the idea is, well, I don't move that much, so I must not eat that much.
And it kind of goes back to what you said initially, the self-monitoring behaviors, which, you know, I think about awareness of what you're doing helps you realize what's actually going on. So, you think you're not eating that many calories. But in reality, if you're sedentary, based on the best research that we have, which there's quite a few studies on it, as I understand, you actually eat more because your appetite's higher and it's a bit like, whoa, wait a minute. I thought...
Because exercise is supposed to stimulate your appetite and it does at the higher levels, but people are so sedentary that it, I think our whole idea of what's active, what isn't active as Americans in particular, it's gotten so extreme that we don't realize no, you're, you're actually going to be more hungry.
And I wanted to ask you, why is that the case? I read the paper or, or at least one of the papers on it, and they didn't have an answer at that time. They said it's multifactorial and, but what is going on there? Is it stress-related? Is it some type of hormonal change that regulates the appetite? Any idea?
Eric Trexler: Well, I would imagine that there are several plausible mechanisms. One that comes to mind is, you know, there, there's one group that proposes that there is a bit of a shift in the primary driver of, of our desire to eat, which is slightly different from hunger, right? So, um, desire to eat, in my opinion, is ultimately what matters.
'Cause there's people who are hungry and choose not to eat, and the calories don't come in. And there's people who aren't hungry and they do choose to eat, and there's your extra calories, right?
So, desire to eat..., when we are very low on the spectrum of physical activity, it seems that hedonic drivers of eating are, are really dominant in that setting, in that scenario, which means that people are eating basically to fulfill enjoyment, um, which makes sense. I mean, we have a neurophysiological reward response to food that tastes good. And so when, when physical activity is really low, our energy consumption is kind of decoupled from our actual energy needs, which are dictated by energy expenditure.
And so what we see is that people's choice to engage in hedonic eating or their kind of habitual behaviors associated with hedonic eating, that seems to put them at an energy intake level that's incompatible with theiir actual energy expenditure. And it's, it's higher than, than their actual true energy needs.
And what we find is, for some reason that I don't think we fully understand, as people start to move up and do more physical activity, they move up that spectrum. We see that energy, the, the drive to eat starts to become recouped to energy expenditure. So instead of having this kind of excess hedonic eating that's putting them above their energy needs, now their appetite and their desire to eat seem to be more tightly regulated by the number of calories they're actually consuming on a daily basis.
And so, and then that relationship holds. And what we find is then when they start doing a ton of exercise, they just start getting really, really hungry because they actually need the calories. Right? I mean, if you're exercising, you're burning, you know, several thousand calories a day. You're going to be hungry. That's, that's how bodies work, right?
Another mechanism I've seen that I think is interesting, but there's probably more work that needs to be done is this idea that there can be an appetite suppressing effect of elevations in core body temperature. And perhaps what we're seeing is kind of this residual effect for hours after an exercise bout where higher core temperature and, and when I say hours, I mean we could see some modest elevation for 24, maybe even 48, to be honest.
I have seen researchers who use core temperature as kind of a surrogate for physical activity because of the increase in basal uh, expenditure that can persist for up to 24, 48 hours. So, all that is to say perhaps maybe core temperature elevations have something to do with this, what they would call an anorexic effect of, of exercise or kind of a slight appetite-suppressing effect, which like I said, kind of just depends.
You get into the exercise appetite literature, it's, it's really messy 'cause it's, you know, well, is it a questionnaire or did you actually measure how much they eat? And did you do it two hours after the bout or the entire day after the bout? It gets really messy and there seems to be a lot of variability in the data.
But what we do know is, you know, it does seem that exercise can, in a lot of folks have a pretty noteworthy impact on appetite and desire to eat. A lot of times going from sedentary to at least lightly active tends to have a positive effect rather than, you know, a lot of people think if I exercise more surely then I'll be inclined to overeat.
But I tell you what, I, I don't want to get too far off topic here, but I, I, I meant, meant to mention it earlier and I, and I skipped over it, but, you asked a little bit about, you know, what is dictating success for dieters, and now we're talking about appetite. And one of the things that I think is a huge revelation when it comes to weight loss is the remarkable success of the newest wave of weight loss drugs the pharmaceutical interventions these incretin agonist drugs.
So things like semaglutide or, you know, Wegovy uh, Mojarro, you know, and there's a new one actually. Um, That, that actually is a glucagon agonist as well. Uh, so, so they are agonists for, um, you know, GLP1 and GIP, these hormones associated with appetite regulation and insulin release.
And what's really amazing is that people are taking these drugs and their not just hunger, but also desire to eat is, is going down considerably. And people who had been so resistant to weight loss, I mean, some of these trials were seeing average weight loss values in a year of 30, 40, 50 pounds.
Uh, for people who, if you would've told them, you know, Hey, we're going to do a one-year intervention. They'd say, I'm either, I'm going to lose zero pounds, maybe five, hell, I might end up five pounds heavier. Right? Um, you know, there, there are a lot of folks who struggle with weight loss and end up actually, you know, they lose five, they gain back 10, and they say, why don't I even try?
To be honest, I think we have a lot to learn in terms of the neurophysiological determinants of who responds better or worse to diets. I mean, we can see some of these trials where they'll use functional MRI, FMRI where they can kind of look at blood flow as a rough proxy of brain activity. Some people just respond differently when you give them a milkshake, right?
And some people have different magnitudes of reward responses to food. Some people have different, you know, neurophysiological responses to energy intake, energy restriction, weight loss, and I think we're, I think we have a lot to learn there, and I think ultimately that's going to be a very impactful area of separating who tends to succeed in these weight loss endeavors and who tends to really struggle.
But I will say, as someone who has spent more time than anyone ever should thinking about metabolism, studying metabolism, I struggle to think of a scenario where someone's struggling with weight loss and I say, “you know, what we need to do is change something about your metabolism.” That basically never happens. You know, there are people who are definitely very resistant to weight loss efforts, but I think it has a lot to do with other factors and very little to do with metabolic rate.
You know, because if we just had some drug out there that could just ramp up your metabolic rate, we do. DNP, bodybuilders have been using that forever,
Ted Ryce: sometimes kill themselves accidentally.
Eric Trexler: it sucks. It, it's a terrible drug for a weight loss intervention because when you take it, you're, I've never had it, but when, when you take it, I assume that you're tremendously uncomfortable. If you take too much, you're sweating like crazy.
And I believe your heart rate is probably pounding and you know, yeah. If you take way too much, then you die. And ultimately, you know, you're burning more calories every day. But that's a very small element of the weight loss equation. It matters, but it, it's not the end all be all. And in comparison, we look at these actual effective pharmacological interventions and what are they targeting? Not energy expenditure. They're, they're targeting neurophysiological and, and gastrointestinal responses to food.
Ted Ryce: Or your appetite and desire to eat. And cravings. Or however you want to put it. That's the real, and you know, I'll just come out and say it. That's the real challenge for people.
It's the appetite. It's always the appetite. It's always, like you said, the difference between hunger and hedonic eating or um, cravings, however you want to, whatever you want to call them. If you can master that, you can get great results.
I mean, we're, we're kind of coming up here on we're, we've been at it for 45 minutes. I would love to have you back on the show to talk about the weight loss drugs and some of that.
Because I'm in Brazil right now and they're having issues with that drug because people, so, correct me if I'm wrong here, Eric, but that drug is indicated or it's medically prescribable if you've got a BMI of 30 and above.
So, it's not like, oh man, I just want to lose this last bit around my, my waist here. That's not your, your doctor's not going to give it, or at least not legally going to give it to you. And they're having a problem here.
I think in the states I read about it too, but in Brazil they're having problems 'cause people who are maybe just a little bit overweight or want to lose that the, the belly fat that they can't just get rid of because they're eating too much cheese and bread, they're taking it.
So, yeah, such a fascinating conversation and so many ways to take this. But what are some, to finish off our conversation here, what are some of the best ways to manage, or first of all, to get someone aware of what the actual issue is? I would love to hear, 'cause you coach people too.
What are some of the issues that you find selling people on this idea that, hey, this isn't an age metabolism hormone thing. This is a, this is a, hey, your, your desire to eat goes up. Um, some people have different desires to eat. Some people, when they have a milkshake, it really lights up their brain. Other people, it's just, hmm.
They may finish half of it, but it's too sweet. So how do you get people, um, sold on that idea, coach people through that?
Eric Trexler: Yeah, it's tough. I mean, What I usually do with folks is, you know, it, it's got to be a conversation or really a series of conversations. But a lot of times, you know, the way it happens is someone says, I'm eating way too little and I'm still not losing weight fast enough, or at all, you know. So, that's usually where the conversation starts.
And I think the first thing you have to do as a coach or someone who's just talking to a friend or a family member is you know, have some compassion, have some empathy, you know, and say, yeah, I understand, you know, I. You know, I think I understand how you must feel, what you must be going through, and you talk a little bit about it.
And then when the time is right to get into more solutions-oriented parts of the conversation, you say, why don't we do what I, what I call an energy audit. Basically we just go through the day and try to figure out where might we be underestimating calorie intake or overestimating caloric expenditure.
And so, we'll go through really meticulously and you know, it'll be, you know, okay, well you had that for dinner, but did your, did your son finish his dinner? No, he didn't. Okay. Did, did you eat the other three chicken nuggets that weren't yours? You know, so with parents, that's a big thing, is finishing their kids' food.
Or you know, oh yeah, I did, I did take the kid out, the, the kid's out for ice cream and I forgot to mention that. So, a lot of times you can find these calories here and there, or you'll find that people are overestimating the amount of physical activity they're doing or the, the caloric expenditure associated with it.
So, first thing is to kind of talk through and say, well there's really no mystery going on here. You know, we're going to be able to find where the missing calories are. We just have to make sure we're being methodical and very detail oriented. And that has to be a supportive conversation.
It cannot be an interrogation where it's like, let's find out where you were wrong or lying. 'Cause you know, if we look at the research, we find people who report being resistant to weight loss and say, you know, it's got to be my metabolism. There have been studies where they find, oh, they've been underestimating their intake by X percent and overestimating their expenditure by y percent.
But even registered dieticians in America, that's kind of the highest credential you can get as a practicing nutrition professional. Even registered dieticians in a study were found to underestimate their intake by I think 20%. And if you ask me who, who is the most qualified to accurately estimate their intake, it would be a registered dietician without question.
Certainly more so than a medical doctor. Any other profession really. Even someone with a PhD in nutrition, you know, a lot of people with a PhD in nutrition study, like one like element of vitamin C or vitamin D receptor, you know, you get such in such a narrow thing. It's like you might not even really have a lot of the like practical day-to-day nutritions.
You might, but you might not. But registered dieticians are in the trenches every day working with clients, talking about portion sizes and energy content. So, yeah, a lot of folks are making errors in their estimation and they're honest errors. You know, it, it's most likely an error, not a lie. So we talk about that and then we figure out, okay, so now we kind of have a better sense of the actual nuts and bolts of the problem here.
We've got a more accurate assessment of where we're at. So now our challenge is we need to find a way to make sure that we're eating in alignment with our goals or exercising in alignment with our goals. And then we start talking about feasibility. What is the most tolerable thing we can do right now to get you on the track that you want to be on?
Sometimes it's exercising more, more often if it's a weight loss goal. We're going to be talking about dietary changes. And then a lot of times the conversation, as you alluded to, becomes, how am I going to do that sustainably? How am I going to not have this overwhelming desire to eat these cravings, you know, this hunger that I'm working against?
And that's where we get into some really practical strategies. So things like changing food selection and you know, eating meals with lower energy density. So things that take up a whole bunch of room on your plate or in your bowl without providing a ton of calories. So, things with a lot of fiber content, water content, a lot of fruits and vegetables that aren't calorically dense.
That's where we start. We'll even talk about little things like food texture, eating harder foods rather than softer foods. It can actually make a difference the eating environment, eating in a way that you're not super distracted, focusing on your food, that can make a difference. And when you do that, you often eat more slowly, which can have an independent effect as well.
Uh, and then even, you know, beyond just kind of, you know, having low energy density meals, we'll even talk about palatability. Which is a fine line. So, with palatability, we want our meals to be palatable enough that we can eat them. We, we don't want eating to be a chore necessarily, but we also don't want it to be a, a genuine, we don't want be devastated when the meal's over.
Right. If we're, if we're dieting, probably not wanting to have a delicious milkshake for dinner. 'Cause when you finish that tiny milkshake, which is going to be calorically dense and extremely palatable. Extremely tasty. You're going to want to go for seconds when you know you probably shouldn't based on your calorie target.
And so, in a weird way, a lot of times people start dieting and they, they think about how do I maximize the tastiness or the palatability of these mere 2000 calories that you've allotted me, that's the wrong line of thinking in most cases. What we need to be thinking about is how can I create a diet with palatability that's appropriate for my goals and my response to diet palatability?
So sometimes I'll actually tell people, let's try to make our meals a little bit more bland and they'll say, but I already hate my diet. And I'm like, well, you hate your diet 'cause you have these little bits of gold in there, and then you're just missing those all day, right? You have 'em, they remind you what you're missing and you say, man, I can't wait for that next meal.
In some cases, we'll actually leverage palatability in a very counterintuitive way and we'll say, Let, let's not mix those little treats in, let, let's have a boring diet and see if that serves us a little bit better, at least in the short term and possibly even in the long term.
And, you know, there's certain foods that, you know, some people just don't keep in the house anymore. And, and that's not necessarily a terrible strategy. If there's a food that really drives you to overeat every time you consume it, maybe we don't need to make that part of your day-to-day diet.
You know, there's nothing unusual about making that type of decision and And yeah, so, so we kind of talk through that stuff and look at some of those little strategies and, and then ultimately if we still run into friction, then we start to have the real, the real challenge in conversation with someone, which is, is it possible that the thing we need to adjust is your goal or your expectations?
You know, is it possible that you know there's this particular way of eating and exercising that is not compatible with the way you want to live your life? And therefore, you know, you thought that you wanted to be down at 12% body fat. Is it possible that maybe you can actually achieve, you know, your goals pertaining to health and wellness and fitness at actually a slightly higher body fat percentage, but feel like you're living a much happier, less restrictive life?
Sometimes you do have to have that conversation with people and say, I'm not telling you to be, you know, toughen up and just. You know, put your head down and do it. Let's figure out what kinda life you want to live and see if it's compatible with your fitness goal. And see, you know, if we tried these lifestyle adaptations and these adjustments, you know we tried to adopt these different behaviors.
If that's just not compatible with the way you want to live your life, maybe we need to look at the other side of the equation and kind of find a middle ground. So that's the conversation that you kind of hope you don't have to have as a coach.
Ted Ryce: I'm laughing. I have that conversation. Most of my clients, I have that conversation with. It's a harsh reality, especially if you've been successful financially. It's like, oh, I spend too much money. Let me go make more money so I can keep spending at the same rate. But you can only build so much muscle.
Eric Trexler: Yeah. So you hope you don't have to have it because it's a conversation that has to be had sometimes.
But ideally, you just accomplish all the goals and everyone says, "Wow, I can't believe how easy that was." And you know, shake hands, part ways. Everybody's happy, but a lot of times you do get to that situation where you say, "Well, if our goal is to be perpetually energetic, never hungry, never restrictive at a social event, no need to adjust portion sizes or food selection, and you want to be super lean with a six-pack, eh, something's got to give here, you know?"
That's a very extreme example, but that is kind of the underlying premise, which is that if your fitness goal, you know, if, if we get away from losing weight or building muscle, 'cause body image is so, it's so important. I mean, it's how we see ourselves, you know, so, so there's this kind of visceral personal reaction to it.
But if you think about, you know, just taking it abstract and this can be helpful with clients. I've got a client who says, "I want to win the Tour de France." Well, are you willing to cycle, you know, dozens of hours per week? No. Well then, you know, maybe we just want to win like the local bike race, not the Tour de France.
'Cause like, if, if you want to win the Tour de France, you're on the bike a lot. And if your job simply prohibits you from doing that, then we're gonna have to reassess the goal, right? Or ditch the job.
So, like, you know, when you take it away from these intensely personal outcomes, like my weight, my health, my body image, and you put it into something more, that we're not so personally attached to like, some hypothetical goal of, oh, I want to go win a gold medal in weightlifting at the Olympics.
Well, you're gonna be in the gym a lot. And if you, and if your lifestyle tells you that you only wanna work out three hours a week, you're not winning the Tour de France, you're not winning that gold medal in weightlifting, and that's okay.
But what we need to do is figure out how we're going to integrate your fitness goals with the life that you wanna live.
Ted Ryce: Yeah. Powerfully stated there, Eric. And wow, I feel like we could easily go for another hour here. You talked about so many important things beyond just the metabolism, but this idea of keeping our expectations in check and really being aware of, um, yeah, what, what is necessary to achieve our goal and if it really matches up with the life we want to live.
Are we willing to sacrifice to get there? You also kind of alluded to, this idea of people being really hard on themselves and the tough talk, which is very pervasive in social media. 'Cause it's kind of easy to say, "Ah, you're lazy. You just got to get it together." But I think about my clients, some of which you, you know, some of are obese and they're also serial entrepreneurs worth millions of dollars.
That's not a lazy person at all. We need to have a better conversation. And I love what you said about approaching those conversations with what people are doing and the discrepancy of their results versus what they think they're doing in terms of calories. Just a great conversation today, Eric.
Thanks so much for coming on the show. I would love to have you back on already. I feel like we need to do a part two. Hope you're up for that.
Eric Trexler: Absolutely. Yeah.
Ted Ryce: Cool. I appreciate that. In the meantime, besides going to your Instagram, which is Trexler Fitness, where would you like people to go to?
Eric Trexler: Yeah, you can find me certainly on Instagram, that's my most active social media presence, which is I'd like to say it was more active, but I'm there. I just need to post more, so Instagram's good. Uh, my website is www.trexlerfitness.com. You can also find the Mass Research review at www.massresearchreview.com.
Ted Ryce: Excellent. And I just want to say, if you're listening right now and you're on Instagram, make sure like go right now, click follow. You are going to get incredible information and incredible education on what really matters. I'm just, I, I was looking over your Instagram earlier. Does protein distribution matter?
Does the quality of the protein matter? Are human metabolic rates dropping over time? You just have so much information and so many people are getting their information from just people who I would love to take a marketing course with, but I have like zero interest in learning their techniques.
But Eric, you are the person. Thank you so much for being you for your love and passion of this field and, and bringing evidence-based information to people who need it and to coaches like me.
Eric Trexler: Well, yeah. It was, it was great to be here. Really appreciate the invitation. Fantastic conversation and I'd be happy to come back anytime that you'll have me.
Ted Ryce: Thanks so much, Eric.
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