Dr. Eric Trexler: 0:00

The people who avoid metabolic adaptation effectively are not necessarily the people who have more success with their weight loss or their long term maintenance of that weight loss. There are so many more important factors impacting the success of a diet phase and the subsequent maintenance.

Philip Pape: 0:19

Welcome to the Wits& Weights podcast. I'm your host Philip pape, and this twice a week podcast is dedicated to helping you achieve physical self mastery by getting stronger. Optimizing your nutrition and upgrading your body composition will uncover science backed strategies for movement, metabolism, muscle and mindset with a skeptical eye on the fitness industry. So you can look and feel your absolute best. Let's dive right in. Wits& Weights community Welcome to another episode of the Wits & Weights Podcast. Today I have the pleasure of chatting with the renowned Dr. Eric Trexler. As we delve into nutrition science, psychology and application, we'll explore the intersection of his personal experiences academic research and practical coaching, touching on topics like diet breaks, dynamic maintenance, plant based protein and more. Eric Trexler is a pro natural bodybuilder and a sports nutrition researcher with a PhD in human movement science from UNC Chapel Hill, and several years of university level teaching experience. He's published dozens of peer reviewed research papers on exercise and nutrition strategies for getting bigger, stronger and leaner. Eric has been coaching since 2009, and is passionate about helping people achieve their fitness goals with evidence based and personalized approaches. Eric is also the co owner of the mass Research Review, macro factor app and co owner and director of education at stronger by science, where he writes articles, coaches clients, and is the co host of the stronger by science podcast, which is where I first heard about him and his work, particularly on nutrition and body composition. Eric, thank you so much, man for joining me on the show.

Dr. Eric Trexler: 1:55

I am happy to be here. Thank you for having me.

Philip Pape: 1:58

Appreciate it, man. Why don't we help the listener learn a little bit about you, I've got a couple of personal questions, and then we'll get into some research. So we go back a bit in time set the stage for why you do as you do. Some years ago, you were born in Ohio on a cold spring morning in 1991, as he likes to say. And you wrote that you're short and kind of slow as a 12 year old, you were training to play football. He later got into wrestling and eventually the world that you're in now with nutrition, body composition, all the things I said in the intro. So what I'm curious about is, how did the perceptions of your physical capabilities or your limitations with all those athletic experiences shaped your approach to fitness? And how does that carry forward to today?

Dr. Eric Trexler: 2:38

Yeah, I think I just realized, you know, I was 12 years old, I grew up in Ohio. And, you know, football is one of the major religions in Ohio, and I really wanted to be good at it. And, you know, I never perceived that I had like, major limitations or anything like that. But I you know, I started to realize around the age of 1213. And so as you know, football, they seem to like people that are really big and really fast. And currently, I'm neither. So I realized, you know, if I want to get on the field, see some playing time, you know, I'm not going to be able to just roll up to practice in August and just kind of be in the top spot there. In terms of the depth chart, I realized, that's still accessible to me, it's still an attainable thing, but I'm probably going to have to do more than the people who are a little bit more genetically gifted for what this sport requires. So if I'm going to take that starting spot from someone who's naturally a little bit faster, a little bit taller, a little bit bigger, I'm going to have to find a way to get the edge and the way I did that was by being very meticulous about technique, very, very technical football player, and I got in the gym early and often. And and it kind of created that created that mindset that you know, when there's a goal out there, even if it is not like if you're not just perfectly tailor made for it. Usually there are some strategies that can make it attainable, or at least closer to attainable. And, and that's kind of the the approach that I take generally in fitness, which is to be ambitious, but to kind of temper that with being realistic, and to focus more on, you know, trying to be really pragmatic and saying if this is a goal, and it is somewhat realistic, you know, what are the pragmatic steps that we can take to get there?

Philip Pape: 4:28

Yeah, I like that. So there's a little bit of an optimism bias, right, that kind of positivity paradox, they call it where, you know, you temper it with realism, but at least there's some some major growth that you can achieve Right? Which is, is motivational for people listening, you know, guys like me, who didn't even get started with this until four decades into my life, who may have given up hope, you know, realize that there's always something much greater you can attain to so that's, that's a great lesson right there. Alright, so you've made a point, not to just be involved in the academic side of your research, but also in implementing your research and I'm just curious or at least in in monitoring how it's implemented. So can you share an instance perhaps of when you saw the fruits of your research making a tangible impact on real people?

Dr. Eric Trexler: 5:09

Oh, yeah. I mean, you know, in some studies, you can see it, just with the study participants, you know, I mean, we did a weight loss trial, where, you know, we provided a lot of support to individuals who are pursuing some pretty ambitious weight loss goals, and you can see, you know, just talking to them, because there's a lot of face to face interaction, and research, just talking to them, about how they're more able to play with their children, you know, chase them around the house without getting fatigued and stuff like that they're getting back into hobbies that they haven't pursued in many years. And sometimes we even see our research getting used kind of generalized outside of the actual study participants. So a year or two ago, I had, you know, we did some research on fat free mass in pretty high level football players. And I talked with the entire staff of a really high level football team, you know, top 10 division one type football team, about how they might use fat free mass, when they are the fight fat free mass index, I should say, as a metric when they're doing recruiting, and when they're looking at player development within their program, and trying to kind of set these profiles for what a position might look like. So yeah, there have been ample opportunities to see that stuff, kind of leap off the page and get into real life.

Philip Pape: 6:30

And I'm not sure how many people think about the benefits to the participants in the studies, because when we think of them as just numbers on a page when we're not in there in the trenches, like you are, and that's, it's really cool to be in a field where you're not only gathering useful and helpful data for others, but the process of doing so is helping people as well. Yeah, that's cool. So let's get into some of that research. I was looking at some of your papers trying to figure out where we cover, the first one we'll talk about as diet breaks, you publish the article in the Journal of Human Kinetics pretty recently, I think called the effects of intermittent diet breaks during 25% Energy restriction on body composition and resting metabolic rate, in resistance train females. And you compared continuous dieting to taking breaks every few weeks is what I understood, and to see if there was a difference in body composition and metabolic rate. So tell us about the findings. I'm not going to give it away. Tell us about the findings, any impact on diet breaks as a strategy.

Dr. Eric Trexler: 7:27

Yes. So diet breaks got really popular back. You know, a few years ago, a lot of people were talking about metabolic adaptation, this idea that metabolic rate slows down during dieting. And that's largely driven by reductions in a hormone called leptin. And that gave rise to interest in a lot of strategies where people would increase energy intake for some period of time, try to get leapt into rise for a, you know, transient period of time. And maybe that would help stave off some of these adaptations. And so diet breaks were one such strategy that a lot of people speculated myself included, maybe this will be helpful in terms of navigating those reductions in metabolic rate, and, you know, maybe even helping with some fat loss. So, without getting too far into the details, basically, we did not find in this particular study that diet breaks led to an advantage, or a statistically significant advantage, in terms of reductions in metabolic rate, fat loss, muscle retention, anything of that nature. But we did find one small finding related to kind of more the psychological side of dieting. And that's pretty consistent with other studies in the area, indicating that diet breaks can psychologically make dieting a little bit more tolerable, a little bit more enjoyable. It's never going to be fun. But but there are a variety of different psychology and kind of subjective outcomes related to appetite, desire to eat, things of that nature, that seem to be slightly improved. And I can say, for being a coach, that that's kind of hit or miss, you know, I've worked with some clients who love doing diet breaks, I've worked with other clients who hate it, I use diet breaks as a coach, I don't use them for myself, because psychologically, I don't enjoy it, you know, so I try not to be too dogmatic about you know, should people or should they not use this, but it's more of, you know, what does this tool do and for whom might have be useful? One caveat, I'd like to highlight, we did not see those significant benefits related to metabolic rate or body composition. But there have been a couple of studies showing, you know, a similar lack of, of advantages in those areas. But what we're, you know, the theory there is that it is helping to attenuate metabolic adaptation to some extent, it is worth noting that in these studies where it doesn't seem to do that, there isn't just there's just not a lot of metabolic adaptation happening in the first place, right. So if it's like, Hey, we're doing this thing to attenuate metabolic adaptation. And the participants lose two kilograms over eight weeks, and they're not, you know, super lean, we're not really going to see metabolic adaptation. So even if we were theoretically going to attenuate it, it's, I said, it's like, you know, studying a painkiller. And people with no pain, it's like studying the repellent in a place where there's no BS, right? You're not gonna find anything. And it has nothing to do with whether or not it works. But nonetheless, as I've seen more of this research come out, I am growing more and more skeptical about physiological benefits of this strategy. I think the benefits are more behavioral and psychological.

Philip Pape: 10:37

Yeah. And I think there's gonna be some time to reverse dieting when we get to that. But I did want to ask about the strategies when you do have clients that you use it with? Are you experimenting with a certain standard protocol at first? Or does it based on? Is it based on the situation that they tell you like, Hey, I'm going on, I'm going to be traveling or my weekends, I tend to eat more, or is it something? Is it always highly individualized? Or is there some default protocol you'd like to follow?

Dr. Eric Trexler: 11:00

Well, if we're trying to, you know, just make this there are some instances where we do diet breaks, just because life happens, right? I'm traveling, or if I have a client who has a fairly regular travel schedule, and they're like, hey, every third week, I'm out of town. So well, let's, you know, for work or whatever, let's make that a diet break, or, you know, hey, weekends, it's just super hard to deal with. Let's make that a refeed. You know, we'll do a two or three day refeed on the weekend, around that time. So sometimes these nonlinear dieting strategies, I'll use them just to accommodate, you know, schedule fluctuations and preferences. If I've got a client who is really, you know, we don't feel the most common place, I see this as someone who has already lost a lot of weight, and they still want to lose a lot more, right? And the idea of just saying, well, let's just go in a straight deficit for another 70 weeks, it's just like, psychologically, it's like that is daunting to look down and say, Okay, well, I've been dieting for two years. And let's go ahead and push for, you know, another year plus. So, a lot of times, it's when we're looking at these long timelines for weight loss, and we've got some pretty ambitious weight loss goals. That's where I'm more inclined to go to, let's go ahead and do like kind of a default strategy. What that looks like kind of depends, you know, sometimes I'll do two weeks of dieting. One week, a diet break, sometimes I'll do two and two, sometimes I'll do three weeks of dieting, and one week of diet break. And it kind of just depends on the person. And obviously, the trade offs, there are pretty, pretty simple. The more you know, the more you increase that ratio of diet break to dieting weeks, you are slowing down the process, there's no getting around that. And so if you've got a client who's going to be really discouraged about turning a 20 week diet into a 40 week diet, then diet breaks are not probably not right for them. Or you might do like, you know, three weeks of dieting, and just one week of a diet break. But if you got someone who were like, Hey, I'm going to be dieting for the next year and a half or two years, you know, I want to lose 65 pounds, you know, I've already lost 30. You know, if we're talking about those kinds of really ambitious weight loss goals, where it's just about forward progress, we're not trying to get there in a really, really rapid rate. In those cases, we can kind of slow things down and say, Hey, let's go, you know, to and to, you know, two weeks on two weeks off, or something along those lines.

Philip Pape: 13:32

Yeah. And actually, speaking of that reminds me of some female clients who who might experience a much different hunger based on their cycle. And that reminded me of a nonlinear approach of that sounds very much like what you're talking about a two week on two week off? How common is that use? Or how common is that needed or helpful for for clients that you've seen in real life?

Dr. Eric Trexler: 13:51

Yeah. Specifically with regards to the menstrual cycle?

Philip Pape: 13:55

Yeah, yeah. Yeah, a lot of women listen to the podcast. So yeah, you know, I

Dr. Eric Trexler: 14:00

try not to approach any kind of default strategy for navigating the menstrual cycle, whether it comes to training or nutrition, not because it's an unimportant physiological, you know, cyclical pattern, but because it can vary so much from person to person, you know, the more that I talk to clients who have a menstrual cycle, the more I see that you know, what works really well in this case doesn't work super well, in that case, and mass is the research we publish research review we publish every month. Our new co author is Lauren Kalonzo sample, and she is a leading expert in this area. her dissertation has a lot to do with female sex hormones. And she's written papers about training around the menstrual cycle. And, you know, in talking with her, you know, someone who is just absolutely dialed into this literature, she tends to advocate that there's really no a one size fits all approach for these types of modifications. So that doesn't, that doesn't mean you shouldn't do anything. But it means as a coach, hopefully, you've got really a really good coach client relationship where you can have that open dialogue. And so, like for training, for example, I don't say, oh, you know, your menstrual cycle is coming up. So I'm going to assume we need to make these three changes to it. But if my client says, Hey, I'm having some menstrual symptoms, today, I'm really not feeling up for this type of workout, then we go in and modify a few workouts, you know, around those symptoms, rather than saying, oh, because you're in this phase of the cycle, we're going to, you know, kind of dazzle ourselves with all these kind of mechanistic hypotheses about how your training should change. And I take the same approach with nutrition, if it's a situation where an individual experiences particular food cravings at a certain time of the month on a regular, you know, kind of cyclical schedule, you know, sometimes it makes sense to do a plant hedonic deviation, or to do a refeed. Sometimes, accommodating those, those cravings can actually backfire. You know, sometimes, if you know, those cravings are there, you say, oh, cool, then let's increase calories by x, you know, the fact that there's now been an allowance for extra calories, sometimes we increase calories by 2x, or 3x, you know, because it's kind of like, once the floodgates are open, you know, that, then we're kind of into, you know, a bit a bit of overeating that deviates from the plan even more than that kind of accommodation that's been made. So, for some individuals, we might even say, oh, cravings, you know, let's do, you know, a strategic increase in calories, we might find that it's really hard to rein it in, when those calories go up. And then in future months, we say, okay, that, that wasn't good for us. You know, that's, that's why I personally, you know, like I said, I, while I've done research on refeeds, and diet breaks, and I find them fascinating. I've used them for clients, I don't use them when I'm dieting, because once I start deviating from my typical daily intakes, I now want to eat way more than I used to, you know, it's kind of once I start kind of going beyond that kind of easy, predictable daily calorie intake. It's like when I'm when I'm locked into that routine, I don't even really think about overeating that much. But once I'm going above that, I say, Wow, this is really cool. I wouldn't mind going even higher, you know?

Philip Pape: 17:28

Exactly. In that point, you're like, I might as well be in a muscle building phase. Now that's gonna be my diet break for the next six to nine months. Yeah, exactly. All right, cool. No, I just does interesting tangent I wanted to explore. But I do want to talk about reverse dieting for a bit, because you did write the popular and maybe notorious in some circles article titled reverse dieting hype versus evidence, you disect the evidence on on reverse dieting, which I know you will personally behind basically pioneering that maybe even the term itself, correct me if I'm wrong, but claims about it, why dynamic maintenance, which I want you to get into a bit is more aligned with the evidence and is simpler, it's a less stressful way to potentially recover from a diet. So tell us why. What drove you to want to write that article? And then what the response has been? And we can get into some of the details of it?

Dr. Eric Trexler: 18:16

Yeah, yeah. So you know, reverse dieting, I certainly didn't come up with the topic. But I, to the best of my knowledge, I think I'm the first person to use it in a peer reviewed paper. And maybe even the second person as well, because I was writing a lot about metabolic adaptation between 2014 and 2017. And kind of introducing some of these ideas into an area you know, they were they existed in the fitness industry, but no one in the research world was really talking about them much. Because no one in the research world was kind of embedded in that kind of corner of the fitness world. So yeah, it's something that I was very interested in, and actually quite optimistic about when I first started looking into it and thinking about it and writing about it. As the years went on, I became less convinced about the kind of under the theory kind of underpinning it. The idea is, you know, after a diet, this metabolic adaptation has occurred. If we look at the extreme case, you might, we might find a physique athlete who got shredded for a competition and their sex hormones are low, their thyroid hormone is low. And when I say low, I mean typically well out of the reference range. Like if you went to your physician, and I've done this before they go, what's happening, some something is wrong, right. And, of course, it's just your underfed, right. It's not like there's a there's usually nothing too catastrophic going on. This is a normal response to an abnormal thing that you're putting your body through. Doesn't mean you should ignore test results. But you know, it's pretty easy to understand what's going on there. Once you talk to your physician, but anyway, low low sex hormones low thyroid hormones, you know, energy expenditure tends to be quite low in this state. And so you see that you're dieting on lower and lower and lower calories as you get into this kind of really restricted state. Now, physique athletes, that's where this idea got popular because they, if possible, they love to get back to a normal calorie intake for them. So, you know, I've been in situations where I'm dieting on under 1500 calories. And I'm like, you know, I'd love to climb back up to 2600, or 3200. But stay shredded, because who wouldn't? Right? That'd be great. As long as I feel great when when I kind of get back up to a higher intake. And so the idea was, okay, if energy restriction is causing these adaptations that are very unfavorable, and make us kind of feel like crap, perhaps we can do the opposite of that we can reverse it. Hence, the term reverse dieting, which is, instead of slowly reducing calories over time, we slowly introduce calories over time. And the idea was, maybe we can recover from an endocrine perspective hormonally. Going from negative energy balance to neutral energy balance, where instead of losing weight, now we're maintaining weight. And maybe, you know, there are some studies where, you know, they'll bring people into the lab, overfeed them by like, 800, or 1000 calories a day. And what do you know, their energy expenditure goes up, you know, they're just full of all this extra energy. And so they start fidgeting more, and their basal metabolic rate goes up. So the idea is, what if we can kind of get people recovered from a hormonal perspective, and nudge their energy expenditure upward by just slowly increasing these calories. And the idea that has been popularized is that you can keep doing this to a pretty significant extent, just kind of go up and up and up. And all of a sudden, you have these, in theory, people that are still like stage ready, bodybuilders who feel great hormones are normal ranges, they're eating plenty of food, and they're just shredded. So that's the concept. But unfortunately, for a lot of reasons that I mentioned in that article, it just doesn't seem to work out that way. You know, the, the physiological state like I said, overfeeding from your kind of natural body weight is going to increase your energy expenditure for most people. Now, it varies a lot from person to person. But if you are like doing like an eating competition type of overfeeding, you will increase your energy expenditure. But that's a very different physiological state compared to refeeding from being at a reduced body weight. And so what we see is when people are so like I said, overfeeding from your typical body weight, very different from reintroducing high food intakes. When you have been dieting for many, many weeks and lost a lot of weight, what we see is that there are a number of adaptations that occur such that we are more predisposed to kind of easier and more rapid fat gain after a significant fat loss phase. So that overfeeding process that occurs, or the kind of observations we see from people who have not been dieting really do not translate to people who have been dieting. So that's a really important point is that we have a huge difference there. There are also some points I make in the article about different metabolic phenotypes, spendthrift versus thrifty the getting into the details of that is probably excessive for our purposes here, but

Philip Pape: 23:35

go read the article. I can throw it in the shownotes. Yeah, but

Dr. Eric Trexler: 23:38

but the general idea is, when we look at the research on metabolic phenotypes, the people who would stand to gain the most from reverse dieting, are the least likely to actually experience any increase in energy expenditure when they slowly reintroduce calorie. So I wrote a very, very long article kind of exploring, not just why I am very, very skeptical of the concept, but also why it often seems like it works. Because I know a lot of if you if you're listening to this, you're like, Well, I don't know, I saw someone on Instagram. And they said that they reverse dieting, and now they're still very lean, and they've increased their calorie intake by 600 calories a day. I don't dispute anything in their, you know, their anecdote of what they have done. But I do dispute some of the underlying physiological conclusions that a lot of people draw based on those observations. I think, in most cases, the kind of really eye opening success stories we see from reverse dieting, working, it's really more of an illusion, that can be explained in a pretty straightforward way. Yeah,

Philip Pape: 24:49

and there's two things that come come out of this I wanted to follow up on one is the practical or logistical reasons. Some times people give, you know, like, well, I can't jump back by 1000 calories overnight, you know, Is that Is that a valid concern? But it also has nothing to do with why we say reverse dieting does or doesn't work. Would you agree?

Dr. Eric Trexler: 25:10

Yeah. Yeah. I mean, if someone is hesitant about making a large increase in I mean, if someone wants to maintain their weight, or if they're a little bit nervous about, you know, if they at least want to attenuate, weight regain, if they want to stay pretty close to where they've gotten in their diet, well, then it probably doesn't make sense to jump 1000 calories overnight unless they're in 1000 calorie deficit. And most people at the end of a diet are not in 1000 calorie deficit, that's a big deficit. And usually the deficit shrinks over time, as the diet gets harder and harder, we're less inclined to make these big, big cuts, usually, rate of weight loss slows down. And that's indicative of a smaller deficit. But so yeah, I mean, I, I would totally say, Oh, if you don't want to increase your calories, 1000, then don't you probably don't need to in order to maintain what you've got here. But But again, that's doesn't really make an argument for reverse dieting. Right? It just is kind of an unrelated topic,

Philip Pape: 26:08

right. And then the other piece is the idea of dynamic maintenance, that perhaps the reason people jump to, by too many calories and say, well, we need to reverse up is just the lack of understanding where their maintenance is at that time. And I think that's a great concept that, that I've learned personally, I mean, that's honestly been a game changer, this idea of tracking your maintenance, and being as accurate as you can, using apps or whatever it takes, so that you can adjust weekly, but also get out of a diet as quickly as possible. So maybe just I still think a lot of people aren't 100% aware of that concept, or they may not use apps that use that concept. So maybe talk about that a bit. Yeah, so

Dr. Eric Trexler: 26:45

the idea with dynamic maintenance is exactly what the name implies, which is that your maintenance calories today, so the calorie intake, that's going to help you maintain your current body composition, is probably not the same number that it's going to be in six months, or a year or in 18 months. And if you're dieting or gaining weight, it's going to change a lot through you know, even someone who's trying to pretty much stay the same, it's going to change over time. But if you're throwing in weight loss phases, and weight gain phases, your maintenance target is going to fluctuate a lot. And so what we find is, when someone is dieting, and they get down to the end of a diet, their maintenance calories have dropped, it's essentially unavoidable. And that's not the maintenance level that they're gonna stay with the rest of their life, when they get out of a calorie deficit, just that alone is going to increase their basal or resting metabolic rate is going to kind of come back closer to where it ought to be based on their body size, like, just simply getting out of a deficit is going to increase your daily energy expenditure. And so what happens is, people get to the end of a diet, they say, okay, I'm good, I've wanted to lose 20 pounds, I lost 20 pounds, I'm going to increase my calories, just enough to get back to maintenance. And when they do that, since they are no longer in a deficit, they probably will observe that their maintenance level actually starts to go up a little bit, because instead of being a negative energy balance, now they're a neutral energy balance. And so then, because their energy expenditure has gone up at at this new calorie intake level, now they find themselves in kind of a small deficit again, and they can bump that up just a little bit. And what we see is that reverse dieting basically posits that if you just kind of force your intake up little by little, that metabolic rate will catch up because you're driving it up. In reality, dynamic maintenance is the idea that it you are basically catching up to these this drift of your maintenance level. So it is dynamic. As you continue trying to achieve maintenance level or neutral energy balance. It will keep drifting away from you as you start to get back to where you started. And so it's not that the nutrition changes are driving metabolic changes. It's that are you know that you're forcing your your metabolism up, it's that by getting back to neutral energy balance, your metabolism will drift upward. So you're not trying to kind of force it to do anything, you're just getting to maintenance and if it responds and starts drifting up, you are catching up to your increase in metabolic rate rather than driving it up from proactive food changes.

Unknown: 29:30

Before my coaching session with Philip, I was really struggling with staying consistent with my nutrition. Phillip really showed me the importance of being consistent day to day, he also helped me see that it's not a bad thing to take a rest day. He really helped me get in that more positive headspace of a rest day being something really good for me. I've been doing this for a month now. And I'm finally starting to see some progress and my numbers and I'm really excited about that and I just appreciate so much The help that Philip has given me, he's always willing to answer questions to offer resources that are totally free and very, very helpful. So I just want to say how much I appreciate that. Thanks, Phil.

Philip Pape: 30:15

Yeah, it's pretty crazy how somewhat consistent This is, especially with an individual, when they've gone on multiple cycles of gaining and losing how, you know, I know for me, personally, I lose 600 calories on my expenditure. And then boop, pops right back. And all of a sudden, I need to really up my calories when we go. And so tracking that is extremely important for it. Cool. So what about the flux aspect of this? Because I'm really curious about energy expenditure and flux, which, you know, the science behind that informs a lot of your work, I think, and I'm just curious about that concept. So tell us about it.

Dr. Eric Trexler: 30:49

Yeah, so energy flux is kind of the idea that, you know, we can look at energy balance, as just, you know, calories in versus calories out intake versus expenditure. And if you get to zero, you're in neutral energy balance. But the idea of energy flux is more looking at, you know, what is the absolute amount of energy kind of going through the system. So what that means is, if you're very, very sedentary, you know, you might have maintenance at a certain calorie level, let's say, it's, you know, I don't know, 2200, obviously, it's going to depend on your body size, but someone who is very, very active, their maintenance level is going to be much higher. And so, you know, if they're maintaining at 2800, instead of 2200, they're having more energy flux, because their energy expenditure is higher, than they are going to be consuming more energy to achieve any particular body composition goal. And so what's really interesting is that, you know, some folks have posited that a high state of energy flux tends to be just kind of generally better. You know, in terms of cardiometabolic outcomes associated with with doing more exercise, people have talked about high energy flux states being better for kind of long term weight loss outcomes, long term body composition outcomes with weight loss attempts. So energy flux is basically talking about not just where you're at in terms of net energy balance, but also how much energy are you can? Are you burning through on a daily basis? Kind of shifting that entire equation up or down? Relative to your daily energy use?

Philip Pape: 32:31

And is it better? To say,

Dr. Eric Trexler: 32:35

you know, it's tough, I think, when I'm talking to somebody with a particular goal, and when we're talking about energy flux, we're really just talking about physical activity level, like, that's really what's going on here that that's the lever we can pull, if we're trying to manipulate energy flux, or, you know, just energy expenditure, and kind of shift that entire energy balance equation up or down. When someone asks, you know, how much cardio do I need to do? I mean, you can get into real, you can get very, very lean doing minimal cardio, you're going to need some resistance training, if you want to retain muscle mass. But the question is, is there any benefit of having some extra cardio in there along the way, depending on the goal, typically, kind of, you know, so people tend to studies tend to find, I should say, that long term weight loss outcomes do seem to just be better when people maintain high physical activity levels, I don't necessarily know if that's because of energy flux, I think it might just be a simple indicator of, you know, sustainable behavior change that he puts on monitoring my health behaviors, I'm engaging in them, part of my weight loss journey was doing some exercise, and therefore I can maintain better when I exercise. So the long term data in terms of weight loss and weight maintenance do look better, in people who do a decent amount of exercise doesn't mean you have to do a ton. But for that particular outcome, you know, being in a physically active high energy flux state is a positive thing. You know, the same thing goes, the cardio metabolic benefits of exercise, totally unrelated to weight loss are immense. And being in a high energy flux state is going to be better for that. But, you know, people ask, well, do I have to do cardio to achieve a particular physique? That then my answer would be? No, you know, most people, if you're comfortable reducing your calories enough to get there, and you're lifting weights, you don't have to be you know, doing a bunch of cardio or getting a bunch of steps in in order to achieve those types of results.

Philip Pape: 34:41

For sure. And I guess I didn't realize I was basically asking the question, should we do more cardio when you were talking energy flux, I hadn't totally closed the loop on that's, that's effectively what we're saying. Right? So use this terms and pretty much confuse everybody and we're like that all we mean is move more like just move more and you're gonna burn burn more calories, and that causes more fluctuation in energy at that age. Under level.

Dr. Eric Trexler: 35:00

Yeah, and one thing I should also mention is, this is really important, doesn't get talked about a lot. But physical activity, like I said, it seems to correlate with long term outcomes really well. The other thing is there is an interesting relationship with physical activity level and appetite regulation, what they find is that when you increase from very, very sedentary to moderately active, it tends to help with appetite regulation, and actually kerbs over eating to some extent, what it does is it re couples your appetite to your energy expenditure, what we see is in very, very sedentary people, that becomes a little bit uncoupled and eating behaviors and appetite are kind of driven by more hedonic drivers, rather than, you know, just I need energy to account for my expenditure. So what we find is that we are kind of shifting appetite regulation away from key Donek drivers and toward, you know, just kind of pure energy balance as the main driver. And then, of course, as you start to go from moderately active to extremely active, you eat more, because you're exercising like crazy. And, and you get sense. Yeah, so. So there are benefits, yeah, benefits going from very sedentary to moderate. But once you're moderate, and above that, it's all pretty much the same.

Philip Pape: 36:20

And isn't that the case with just about any health promoting activity, one tends to drive the other. And it's why wherever you can start, you know, when you're listening, we talked about this all the time, wherever you can start today start because I might start driving these other behaviors. Okay, so I want to talk about plant based stuff. So plant based protein and some other things, right, because I understand you're fully plant based now. Indeed, yeah. Let's assume the listener already knows the basics of protein, like they need enough protein they need to spread throughout the day, they want a variety of sources for that protein for a healthy dietary pattern. So with that assumption in place, how much should we be concerned about the differences between animal and plant derived proteins? And where I'm going with this is there's a lot of lot of ways you can measure these differences, right? You could talk about the amino acid profiles, quality digestibility the effect of health markers if we're looking at cardiovascular health outcomes, like hypertrophy. So what's the practical stance on all these differences in someone's just trying to plan what's on their plate?

Dr. Eric Trexler: 37:19

Yeah, I mean, if you're getting plenty of protein on a daily basis, I really wouldn't worry about it much at all. You know, when we look at the studies that are trying to find the kind of optimal protein intake, you know, I mean, most Americans get a decent percentage of their protein from plants anyway, those are the people doing these studies. And then when you get outside of America, the percentage gets even higher of the percentage of total protein coming from plant based sources. So that's already baked into the literature, which is something that a lot of people don't don't really talk about. You know, depending on what country you're in, it could be like a 4060 split or like a 6040. Split. But no, no, wait

Philip Pape: 37:59

a minute, that is a little surprising. So are you saying that in America, the standard, the average population gets more than protein from plants, but it's because their protein intake is fairly low? And then they tend to add more animals? I

Dr. Eric Trexler: 38:11

think, I think in America, I have to recheck the paper that is buzzing around in my head right now. But I think it's I think it's 40% coming from plants. Yeah, not not the 60. I think it's 40% plants. But there are some countries where it's inverted. And I think as much as 70% of protein is coming from plants, so But But basically, the point is, when people see, oh, you need this many grams of protein per day, they kind of assume that it has to be these high quality proteins. But it's in a study where if we just want to be really lazy with the numbers, maybe about half of the protein these people are eating is coming from plant based sources, you know,

Philip Pape: 38:52

that includes grains and things like people don't always think about Yeah,

Dr. Eric Trexler: 38:55

yeah, they're not all eating tofu, right? Because if you're not a vegan who would, right? It's grown on me. It's grown on me. But I have plenty of omnivorous friends who think I'm insane for how much tofu terrible depending on how you, you know, like anything. Yeah, but, but anyway, you know, if you're eating plenty of protein, it really doesn't matter. The place where it really matters is if you are on a very low protein diet, and sometimes people for medical reasons will need to adhere to a low protein diet. It's not typical, but it does happen. Or if you're someone who just you're like, I really don't like aiming for these high daily protein intakes. In that case for hypertrophy, we do see differences. You know, if you're on a low protein intake, someone who's eating a lot of high quality animal based sources, probably will do a little better than someone who's eating exclusively, you know, lower quality plant based sources. So that is the spot where it matters. But as we start getting into daily protein intakes that are up around 1.4 Certainly 1.6 grams per kilogram per day of total protein intake. Once we get up to there, we're seeing these differences are essentially totally gone in terms of hypertrophy.

Philip Pape: 40:09

What about for overall health? Like, I definitely have seen studies that seem to support shifting to more plant based sources for cardiovascular health, for example. And I know as an as an omnivore myself, I do eat a lot of animal sources and wondering, should I continue to work on adding more, you know, plants, other than for the reasons we should? Anyway, nutrients and diversity and fiber and all that stuff?

Dr. Eric Trexler: 40:30

Yeah, I mean, when you look at the I try to look at diets in terms of dietary patterns, you know, and when you look at the dietary patterns that seem to be compatible with just very, very good health outcomes, three that come to mind are medicine, the Mediterranean diet pattern, the DASH diet pattern, and a plant based diet pattern. And so the fact that the Mediterranean diet and the DASH diet both seem totally fine and quite good with long term outcomes leads me to believe that an omnivore if they're just focused on health outcomes, they don't necessarily need to say, Oh, I really need to get more plant based. I need to swap out my animal based proteins. I think what's what we're really seeing there is when you look at a diet pattern, that that's like the DASH diet, or the Mediterranean diet, it's just a well rounded diet, you're getting plenty of fiber, you're getting plenty of vegetables, you're getting plenty of phytonutrients, you're getting all these things that you need. And you're not over eating super fatty meats on a regular basis. And I think that's really the key. So if you're someone who your omnivorous diet involves a lot of refined grains, a lot of really fatty meats and very few vegetables, you would benefit immensely if you swapped out some of the really fatty meats with some plant based protein sources that are probably going to bring in more phytonutrients and more fiber into your diet. But if you're eating a really well rounded, omnivorous diet that's even remotely reminiscent of a Mediterranean diet or a DASH diet, you're probably not going to see much of a difference swapping out your protein sources.

Philip Pape: 42:06

Right. Okay. Those are good benchmarks. I've heard you talk about that before. And I've used those references as well, because they're nice go twos. You know, as much as we stay away from a lot of the names diets, those are pretty good ones. So what about studies that look at omnivorous versus vegan or vegetarian diets are unable to account for all the confounding factors were kind of the normal curve of the omnivorous diet has not as health promoting of a population as people who actively try to eat vegan? I mean, at least that's the assumption I'm making. Does it get skewed? Because of that?

Dr. Eric Trexler: 42:37

Yeah. I mean, they try. Right. So statistical adjustment is a very nuanced topic, and it is a very, inexact science. So these studies, if they're if they're done well, they will try to statistically adjust and account for some of those healthy behaviors that do, in aggregate seem to differ when we compare plant based diet or to an omnivore. Are the statistical approaches perfect? No, they never are. And so those kinds of questions do tend to linger. So they might go and say, Hey, we adjusted for BMI and physical activity per week. And, you know, all these other things, smoking status, the whole deal. They do their best, generally speaking, though, when we look at studies that are really, really well controlled, that do a good job trying to parse out some of those confounding variables, plant based diets versus omnivorous diets, you know, sometimes for it depends what health outcome, right? I mean, there's a lot of different things that that can make you sick or kill you. And the effect for one is not going to be the effect for another But broadly speaking, plant based diet seem to do either they either have similar outcomes or slightly better outcomes compared to omnivorous diets. But how many omnivores are eating a DASH diet pattern or, you know, adhering to a Mediterranean? A lot of times the, I mean, the omnivorous diet is kind of the default diet. Right? Yeah, that sounds a Western diet. Reverse diet, right. So I would venture to say if if you kind of sorted out all the people who were on kind of some of those like very Western diet patterns that you know, have a lot of what we might colloquial meats and things. Yeah, yeah, processed meats, you know, a ton of added sugars, things like that. I think that's where you would start to see those differences really just disappear.

Philip Pape: 44:29

Yeah, cuz I think this is where you see studies on artificial sweeteners, seed oils, you know, the big hot topics today. And it gets so thorny when you look at that because you're wondering if it's just, you know, people have healthy dietary patterns, or people who don't, and they're seeking to be healthier, right? And in case of artificial sweeteners, right, you get all these compounding factors. So okay, I wanted to ask you one one other question about dieting, and that was the psychological aspects of dieting, specifically tracking because there's always a little bit of controversy and there seem to be camps out out there, when it comes to different nutrition coaches and whatnot, do you track I'm anti tracking and this and that, for me personally, I've seen and I've even had some friends who were, you know, maybe resistant at first and I gently asked them to try it out. And they're like, you know, this actually gives me an increased level of awareness. And I can track things like fiber micronutrients and all that. So it ends up being a powerful motivator for some people. And for others, it doesn't work. So well. What are your thoughts on all these aspects of dieting, the psychological aspects in the context of tracking?

Dr. Eric Trexler: 45:28

Yeah, so tracking is interesting, because there's a lot of things we can track, you know, so the kind of classic approach is tracking calories or macros, right? carbs, fats, proteins. And we do have some research indicating that in randomised controlled trials, tracking your food does not seem to cause disordered eating. If you are already highly predisposed to disordered eating, it could certainly cause symptoms to manifest, you know, it can kind of tap into some of those underlying predispositions. But broadly speaking, you know, I don't feel uncomfortable with someone who has no eating disorder history saying, Yeah, let's go ahead and track calories and see how we do. But having said that, it's not the only way to track you know, so a lot of times tracking calories, oddly enough, will bring people a lot of psychological peace. It'll bring them calmness, it's kind of like when you've kind of been worried about your finances, and you finally work out your budget. And you say, No, I know, I can afford that. Because like, I literally crunched the numbers, and I feel good about spending money on myself, because I know it fits my budget. It's a similar thing with calories, where someone looks at that, you know, something that's maybe a little bit sugary, and instead of wondering, is this what's going to hold me back, they say, No, I know, I can fit that in, because I did my my calorie budget. But for some folks, you know, tracking calories, and macros is not going to be the way to go. You can track bigger picture food categories, you can track, some people just do protein and fiber, if I hit those, I'll be good. Sometimes it's food groups, you know, I got my four servings of fruits and my five servings of vegetables, right. And then you can even track getting way into a different realm, you can track elements related to mindful eating, right. So just tracking things like subjectively how you felt before, during and after a meal, what you were focused on during that meal, whether or not you were distracted as you were eating. So tracking can take so many different forms. And ultimately, if you're a coach, working with someone, or if you're someone working with a coach, tracking something is going to be helpful, because it's going to allow for some degree of transmitting data data back and forth. But if you're a coach out there listening, I would encourage you work with your clients and figure out what the right thing to track is, could be calories and macros for many people it is it's a highly effective strategy. But for some folks, you might find that tracking other things, or a combination of things actually leads to to better outcomes for that person.

Philip Pape: 48:00

Do we know if there if there are studies that look at the reasons people don't like tracking certain with certain methods, like calories and macros? Are there good. You know, histograms, you know, that show us that these are the most common reasons, and therefore, you know, that's where we can tackle the kind of resistance to that, for folks that want to do it, but feel like, it's not for them just yet.

Dr. Eric Trexler: 48:22

I'd be stunned if the research hasn't been done, but I've not seen it. Okay. But I can tell you, I can throw my two cents in there as someone who's been in this space for a while. It's I mean, tracking calories is not a convenient thing to do in most cases, right? So sure, a lot of times it's, they don't want to deal with the hassle of it. And for some folks, you know, like I said, if you're kind of, you know, for some folks who have concerns about body image, it can kind of increase awareness of it kind of leads into that, you know, awareness can be good. But if it goes from awareness to fixation, then action starts to be counterproductive. So for some people just with their kind of psychological makeup, as they start tracking things, it's difficult to track and say, Oh, well, now I know and then move on. It becomes something that causes a lot of fixation, kind of being hyper focused on it, and then it starts to really impact quality of life. So I think those are probably the two biggest sticking points. Fair enough.

Philip Pape: 49:24

Do you have a couple minutes for like, couple more questions? Yeah, absolutely. Okay. I was curious what what area of research is really exciting to you right now? Either personally, or something new. That's going on out there?

Dr. Eric Trexler: 49:35

That's easy. Yeah. If you asked me this, two years ago, three years ago, four years ago, I wouldn't have had a good answer. But in the last year or two, there's been a lot of really interesting work coming out, looking at exercise energy compensation. So you might have heard of the constrained energy expenditure model popularized in the book burn by by Herman Ponsor. The research in that area is is fascinating. I mean, it's, I felt really lucky when I was doing my PhD that around that time, the dietary nitrate supplementation research, there were some gaps to really fill in there. And I said, Cool. This is a spot where I can jump in, make an impact, and really, you know, answer some interesting questions. Ever since doing my dissertation in that work. The nitrate stuff doesn't really catch my eye as much, I think we've largely kind of got an idea of what its potential is, seeing this exercise, energy compensation research come out has has really gotten me excited. There's some cool stuff that's been done. And there are still big important gaps to fill that will get filled over the next probably five years or so. A lot of times with research questions, I'll tell people wait 25 years and we'll know Right? With this. It's like no, this is happening right now. It's changing. You know, every six months, there's a new paper that says, Wow, that's, that's an important wrinkle that really kind of changes the landscape here.

Philip Pape: 50:59

Is there a particular paper that comes to mind and we should all go out and check out?

Dr. Eric Trexler: 51:02

I think there's a paper by Karo, CA, r e a u, I think is how it's spelled. That talks. I think that's probably my favorite paper about exercise energy compensation. Ponsor has a review paper from 2016. I forget the title, but it's just kind of a a nice overview of the constrained energy expenditure model. It that's kind of my place to start, if you want to say what's the stuff all about. And then there was a recent paper by Eric Willis and colleagues where they found that compensation appears to be heightened in people who are in negative energy balance versus neutral or positive, meaning that you are getting less bang for your buck, in terms of exercising for, you know, to increase your energy expenditure, if you happen to be dieting, and so that certain people were not what they want to hear. But But totally, I mean, totally makes sense, totally lines up with some of my observations in the trenches, so to speak. So it's it's a really exciting area of research. That is

Philip Pape: 52:04

fascinating. I'm hoping some some of the technology eventually incorporate some of these, you know, findings as we move forward. All right. So I like to ask this of all guests. And that is, is there any question you wish I'd asked you? And what is your answer?

Dr. Eric Trexler: 52:17

Yes. It's a question that I wish was getting asked a lot more. So a lot of times I talk about metabolic adaptation when I go on podcast, or I talk about tangential kind of topics, right? So like refeeds, diet breaks, reverse dieting, all these things that popped up because of concern about metabolic adaptation. But the one question I people ask me, what is metabolic adaptation? What causes it? How severe is it in magnitude? How long does it last? The one question that I wish people asked me more was, How worried should I be about it? Because I can answer all the other stuff and say, well, you're it's probably going to happen in this context. And it'll be about this big. And it probably will reverse if the following things occur. But the question of, should I worry about it? In the way I view the literature, the answer is certainly no. It's good to know about it, it's good to plan for it, it's good to understand that that is a thing that you're going to, to wrestle with if you have an ambitious weight loss goal. But what we what we find in the literature is, basal metabolic rate is not predictive of weight loss success. The magnitude of metabolic adaptation that you experience really is not that predictive of weight loss success, it occurs and it the amount varies from person to person, but the people who avoid metabolic adaptation effectively, are not necessarily the people who have more success with their weight loss, or their long term maintenance of that weight loss. There are so many more important factors impacting the success of a diet phase and the subsequent maintenance. So with all the questions I get about metabolic adaptation, I, I think they're interesting. I like talking about them. They're fascinating. They're, they're informative, and like I said, it is good to know about it and plan for it. But I wish I had more people who would say, by the way, is this something I should lose sleep over? You know, should I be worried about it? Do I need to attenuate or avoid it or mitigate it? Because the answer to all that stuff is really no, just know that it'll occur? budget for it. And when things start slowing down on your diet, now you know why, and we can act accordingly.

Philip Pape: 54:27

That's why I asked you the question, Eric, so I'm glad you brought it up. I'm glad you brought it up. We shouldn't be worried about it. Just like we shouldn't be worried if it's getting our metabolism being damaged or broken or something like that, those concepts and just plan for it. I'm a nerd on this. I nerd out on this stuff. I love the graphs and everything in the following it and see what happens. But you're right, it just it comes back. Right. You. You deal with it and it comes back. You're all good. We're resilient human beings. So thank you, man. Thank you so much for this last question. Where do you want listeners to go and find out more about you?

Dr. Eric Trexler: 54:55

Yeah, the best place to do that would just be Instagram. My handle is at Trexler Fitness. And if you want to learn more about the mass Research Review, which I mentioned in this episode, you can go to Mass research review.com.

Philip Pape: 55:08

And if you're a student by any chance, you can get a little bit of a discount on that as well. So go check it out.

Dr. Eric Trexler: 55:12

That is true. There's a student discount. And yeah, every month we put out on the first of the month, we've never been late. It's about 100 pages worth of the newest and most useful research in exercise and nutrition. We talk about all the stuff we talked about in today's episode, and obviously plenty more,

Philip Pape: 55:30

plenty more almost almost so much. I wonder every month I crack it open like a gift and like which 1am I going to focus on this this month. So good stuff you guys are doing out there. Eric, thank you so much for coming on. I'm gonna add those links in the show notes. And I appreciate you coming on the show. All right, thank you. If you've been inspired by today's interview, and are ready to take action and build momentum on your health and fitness journey, just schedule a free 30 minute nutrition momentum call with me using the link in my show notes. I promise not to sell or pitch you on anything, but I will help you gain some perspective and guidance so we can get you on the right track toward looking and feeling your best