The Science Behind Fasting for Athletes: What You Need to Know [REPLAY] Ep 87

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I'll see you there. Hey y'all, and welcome back to the Find Your Edge podcast. I am excited you're here. So today's episode is a special replay with Dr. Matthew Stratton, a researcher and professor who is now at the University of South Alabama. His research focuses on specialty diets, particularly intermittent fasting, which is what today's episode is all about, to improve health, body composition, and exercise performance. He in particular explores how to optimize these diets for better adherence while maintaining their benefits. So we've taken his research and incorporated it into our Longevity Nutrition Coaching program with an entire module dedicated to it. Additionally, we use genetic testing to determine whether this dietary protocol aligns with your goals. This groundbreaking approach blends nutrigenomics and psychology, offering a comprehensive science-backed strategy for sustainable nutrition and life long health. So let me tell you what happens when you join our Longevity Nutrition Coaching Program. You'll get instant access to over 1,000 recipes, specific meal plans, nutrition and genetic modules, and live coaching calls, all designed to help you make the best choices for your health and fitness. So first, we'll ship your genetic test kit directly to your doorstep. Be sure to complete this as soon as possible as it holds key insights that can guide your nutrition and lifestyle choices. Next, you'll receive a comprehensive checklist to help you understand expectations and set yourself up for success. You'll also get a personalized goal setting sheet that goes beyond traditional SMART goals. Nothing against those, helping you create meaningful, actionable objectives that align with your genetics and your mindset. If you're ready to equip yourself with the tools for sustainable, healthy nutrition tailored to your unique biology and mindset, we'd love to have you join us. In fact, this is your last chance to use our special code, GENETICS2025, for $200 off the program if you get started today. And that expires on February 28th, 2025. So let me say that one more time. Last chance to join us. Use the code GENETICS2025 for $200 off the program to get started today. Offer expires Friday, February 28th, 2025. Head to theenduranceedge.com/longevity. That's theenduranceedge.com/longevity. And let's jump into the episode. All right. So welcome back to the Find Your Edge podcast. I am here with Matthew Stratton recently. I guess we should call you Dr. Stratton now, right?

Technically.

Yes. Fantastic. Congratulations. So he just finished his dissertation at Texas Tech and we are talking all about intermittent fasting. So Matthew, give us a little bit about about, uh, yourself and your interest in this topic, and then tell us about your dissertation.

Yeah. So, um, we had kind of been dabbling around with a couple of intermittent fasting ideas. And so I was like, hey, we want to take this over. And so, uh, that turned out to be still to date, the only study that has been looking, that has looked at, uh, people trying to lose weight while lifting and how intermittent fasting affects that. When, especially when you're, everybody's eating the same amount of food. So that way we can actually look at, is intermittent fasting doing anything or is it differences in food consumption? Um, which is a big thing in a lot of the literature is they don't necessarily control for actual food consumption. They just look at fasting. And then a guy who was the, on my thesis committee was a professor over at Texas Tech. And so he called me up after that and said, hey, we're starting a doc program out here at Tech. How would you want to be one of my first doc students? And so again, can't turn down free grad school again. So I packed up everything from Georgia and moved out to scenic Lubbock, Texas, which anyone who's been out there can tell the sarcasm in my statement right there, where I just spent the last 3 years doing a lot of body comp supplement research. And then as well, because, uh, it's for my dissertation, basically what we looked at was the effect of breakfast consumption on afternoon resistance training performance. So if someone eats or skips breakfast, does it actually affect their ability to perform exercise later in the day once they start eating again? Um, and we did that in resistance training performance. Um, not only because myself, I'm more of a strength athlete, but also because Ironically, it had been somewhat done in endurance performance already. It just hadn't been done with lifters. So we decided to look at it with lifters. And, um, so that was the last 6 months of my life, which, which was a fun time.

Yes. Yeah, for sure. Okay. So let's rewind a little bit. We, we heard a little bit about what you're researching as it relates to intermittent fasting and lifters, but What specifically is intermittent fasting? Because it's one of these things that's been around for eons, but I feel like it's definitely making a bit of a resurgence. It's kind of trendy, if you would call it that right now. So, um, give us the Reader's Digest version of what it is. Yeah.

So like you mentioned, it's been around pretty much as long as mankind has been around. Uh, like you can find references to it even in the Bible. Uh, there are in pretty much every type of religion, there's some version of fasting. In essence, what intermittent fasting truly is, because like not what most people think. So if most people, what you talk to them about, they think about one particular protocol, which I'll mention here in a second, but intermittent fasting is actually a very broad blanket term for a ton of different protocols, um, that basically split everything into different periods of fasting and feeding. So you have a fasting window where Just like it sounds, you consume no calories. And that's the big thing. There's no calories where depending on the type of fast you're doing, whether it's what we call a dry fast or a wet fast. So wet fast, you can still have things like water or anything that's non-caloric. So if you still want to have like, you know, Diet Coke or something like that, coffee, black coffee, that's no calories. That's completely fine. Versus a dry fast is no food or liquid whatsoever. So for instance, something like Ramadan is typically more of a dry fast versus what most people do with intermittent fasting is what we consider wet fast. Um, so you have the fasting period and then the feeding period or feeding window, whichever you want to call it. And all the different protocols, all they do is just kind of mess with either the frequency of how often you fast or the length of the different fasts. And so the most common ones that we see, uh, most common one up until very recently in the literature was what's known as alternate day fasting. Which I kind of stress my students a lot, scientists aren't very original. So we like to name stuff after pretty much exactly what it is. So alternate day fasting is kind of exactly what it sounds like. You, you know, eat one day, don't eat the next day and eat the next day. Like eat Monday, don't eat Tuesday, eat Wednesday, don't eat Thursday, and so on and so forth. However, you know, that's likely not going to be the greatest for long-term adherence. You know, if you ever like get a client and be like, hey, guess what? You don't get to eat at all tomorrow. Uh, might be able to do that a couple of times, but you know, after a while. So then they came up with this thing called modified alternate day fasting, where you find the exact same thing, except you have a really small meal on, um, those fasting days around lunchtime. Typically it's about 300 to 500 calories. So a little bit, and they found a little bit better adherence, but up until uh, the late 2010s, like 2017-ish, that was the predominant one that we saw in the literature. Um, there's another one we don't see in the literature quite as much, but I see it pretty frequently in the field. Um, we term, uh, periodic fasting, which that's where we, again, like I say, where someone is fasting periodically. You're not fasting every day, you're not fasting every other day, you're just doing it every so often. So the most common versions of that we see are things like, um, colloquial term for like eat-stop-eat is a really common one, also known as, um, whole day fasting where someone might do one 24-hour fast. Uh, nice thing about that was, you know, despite, you know, it being 24 hours, the nice thing is you can still eat every single day. Um, cause if you think about it, um, you know, let's say you start fasting at 6:00 PM one day and then you fast till 6:00 PM the next day, you can still, you know, eat kind of breakfast, lunch, and like really early dinner or something like that on one day, and then eat dinner the next day. And so you're still being able to eat every single day, which is nice. Um, and then the most common one that most people associate with intermittent fasting is this one called, um, time-restricted eating is what we call it in literature, or TRE. If you look at all the older literature, so it's kind of funny to say, but older literature around like 2016. So if you go back then, it's time-restricted feeding. Now more commonly we call it time-restricted eating. Um, but if you ever see the TRF versus TRE, it's the exact same thing. And what that is kind of mostly referring to is what, again, what most people think about intermittent fasting. So that's those daily short-term, shorter-term fasts. Um, so like the most common protocol you'll see is the 16:8 protocol, which is fast for 16 hours and then put all your food in an 8-hour window, which for most people sounds like a lot. But if we break it down, so that's eating between noon and 8:00 PM for most people. Now, keep in mind, you can move that window wherever you want in the day. It doesn't have to be noon to 8:00 PM. It's just the most common one you see in practice is noon to 8:00 PM. And, um, What I thought, you know, I deal with a lot of college students and stuff. So I say like, you know, initially you mentioned it, they're like, I don't think I can do that. Like, well, if you think about it, okay, so people like to sleep until the very last second before you have to run out to class. And so wake up alarm, gotta be out of the house 2 seconds later, then likely go to class, go to work, whatever. It's been a little while. Next, maybe didn't really eat that much or at all because you just haven't had time to like sit down. And next thing you know, you're not eating until lunch.

And guess what?

Have dinner a little bit earlier and you're intermittent fasting. Yeah. Yep. Um, so it's, it's pretty close to actually what a lot of people do kind of inadvertently. Um, did there— we do have some more extreme examples of it, like the, what's sometimes known as the warrior diet, uh, is the 20:4. So most— so it's the same thing, fasting for 20, putting all your meals, um, in a 4-hour window. And then there are some more kind of niche variants that are starting to show up. So I have one called like early TRE now, which is— some people are kind of pushing for. A lot of the work for that is coming out of Courtney Peterson's lab, who does a lot of really good work, especially in clinical populations. And I believe she's still at University of Alabama Birmingham. And they— and that's basically doing the same thing, just kind of moving that window to earlier in the And you mentioned clinical population, right?

So is she working with like diabetics or heart disease or something along those lines?

Yes.

You're working with athletes, right?

Yeah. So I deal mostly with, um, healthy athletic populations, uh, because anytime of literature like this, typically the population we don't see it in as much is in healthy athletic populations. Um, but yeah, doing like the main, uh, one of the key early TRF studies, it was in prediabetics. So that's the Sutton 2018 paper, which was in prediabetics, which we like to talk about a lot.

Um, so cool. This is, this is great to get like the very specific information. Cause I originally found you from doing a presentation for the International Society of Sports Nutrition, um, on this topic. And it was great to see all the literature laid out. And then you had this great picture of all the different books that are out on it. Ooh, let me try this diet. But it sounds like there's a lot of different ways of doing this and some of them are well-researched and some of them perhaps not so much.

Yeah. And, and especially depending on the population that you're trying to talk about, I would say a lot of it is not, not as much as we would like to think, uh, because it didn't really start getting popular until only a couple of years ago. And so In terms of studies that combine it with exercise right now, I think we're only at about 6 or 7 studies.

Okay.

Yeah.

So let's, I'm so excited to hear about your research. So you decided to work with strength athletes just because, you know, it sounds like that's a little bit more of an interest for you. So how'd you start? What were your, what were some of your methods?

Uh, the first kind of big one, which was my thesis, that was One where we got, it was about 32 people and then put them. So that was the first study in which we were able to actually like control for diet. And so we put them through a 4-week training protocol where they came in and for supervised training 3 times per week, we had—

are these men and women?

Uh, so this study was just men. And the most recent study we did was males and females.

Okay.

Um, the reason we actually did it with men was because it had somewhat already actually been done with females.

Interesting.

It's one of the few times that you can say like, oh yeah, the reason we did guys is because we can already kind of point to one that's somewhat similar in females. Um, so now we want to do it males. And when typically 90% of the time it's the opposite.

Yep.

And, uh, so we got 32 college-age dudes come in, um, supervised training 3 times per week. So watch them do every single rep of every single set. I got really good at counting to 8 and then basically looked at changes in body composition. So how much muscle mass they grow, how much fat mass did they lose, all that kind of stuff, using— and this was also the first study to use what we say the research gold standard, so a 4-compartment model. Previously just used DEXA, which there's nothing wrong with DEXA. If you're going to use one device, it's still a very, very good device, but it's not the research gold standard. As well as look at changes in things like resting metabolic rate, um, and all that kind of stuff. And so, uh, we tested their resting metabolic rate and then put them on a diet in which we wanted them to be about at the 25% estimated calorie deficit to try to get them to lose weight, which was also one of the big things about this one, because all the previous ones, the goal wasn't really to actually get people to lose weight. So that's a big thing when trying to like interpret a lot of this literature is think about what is the actual What was it trying to achieve? So for instance, the very first study that did this, which was what I think kind of got it really popular, which was the Moro 2016 paper. They, because people looked at it and said like, oh, this kind of semi-controlled diet, you know, people who were doing the 16:8 protocol lost much, lost weight, but kind of maintained performance over these 8 weeks versus the other group didn't. Well, in that study, their goal was actually try to get them to maintain weight. And so that's why they had a really high calorie intake. If you look at it, they were eating, they were told to eat about 3,000 calories per day, which is a really big thing with a bunch of these studies is look at the actual how much calories are being asked to eat, because the dirty little secret about intermittent fasting is typically how it works is we're just tricking people into eating less. And so there's been a couple, there's been a fair bit of studies that show when you put people on these protocols, it's harder to eat more because you know, you're putting it into a shorter time window. So people are fuller for longer. So they're going to, they're going to eat less. And so throughout all of these studies, you know, we kind of see that typically the intermittent fasting group was the one that was generally eating less. Whether they wanted to or not. And sometimes that didn't result in what we call in research a statistically significant difference. So for those of you that— those of your listeners that aren't familiar with that, basically sometimes if you look at numbers, you might see there's a difference right there, but if the difference isn't large enough for us to say it's like a significant enough difference for us to say in science that it's likely that's the thing that's causing it, or that's a real difference. So sometimes that's why we say that like like, yeah, if you look at those two numbers, those numbers are different, but we won't say it's a statistically significant difference. But one of the things—

that was my least favorite class in grad school, by the way, statistics.

It's a lot of people's least favorite. I think— I don't think you need to learn all the intricacies of like ANOVAs and t-tests and linear mixed models and all that kind of stuff, but learning some of the basics about interpretation and stuff like that, I think, can be really important for people so they can understand differences like statistically significant and all that kind of stuff. But I think we run into a thing of statistical significance versus practical significance. And so for instance, in some of these studies, the difference might be so small on daily intake that it was not statistically significant, but that daily intake, when it's compounded over, you know, 8, 4, 8, 12 weeks, whatever the length of the study is, results in a meaningful difference, which, you know, for some of these studies, there might not have been a practically significant difference in calorie intake, but there was, you know, just enough that at the end of those 8 weeks, you know, it was actually what caused some of the body composition changes. And so that's what we were seeing in, in previous research. So for our study, that's why we actually were the first to kind of control for that across the board. So everyone ate around 1,900 calories, 1.8 grams per kg of protein, making sure that they're eating a good amount of protein, um, along with the supervised training. And so we found when diet was controlled, we actually didn't find a difference in strength performance or body composition changes. For my dissertation, we kind of did something similar except more in the acute setting. And so because the most common meal that is skipped with intermittent fasting is breakfast, we wanted to look at, you know, specifically how does breakfast, you know, once people start eating again, does that potentially impact the session later in the day? And there's been a little bit of, there were 3 studies in that. Um, 2 of them were in cyclists and then one of them was in rowing performance. Um, so again, none of them were in, in LIFTERS. That's one of the reasons, you know, we decided to look at that population as well. Also, all of those had been habitual breakfast consumers. And so people who are typically consuming breakfast, not typically people who are typically skipping breakfast or fasting, practicing intermittent fasting, something like that. And that's important because we found with, through a couple studies that there's a large psychological component to it. And this one was done actually in both cyclists and lifters. So if you want to like look up the actual papers, the cyclist paper is the Mears 2018 paper. And then the lifting paper is going to be the Naharudin 2020 paper. Um, but what they actually showed was when they gave people, um, so in the initial studies, they basically had them come in, gave them water or carbohydrate breakfast, and then had them exercise. They found they did that. Um, there was a difference in performance. You know, but then if they gave them water versus a placebo versus a carbohydrate breakfast, there was a difference between water and the placebo and carbohydrate, but no difference between placebo and carbohydrate. So that's showing that pretty much all of the performance decrements that were shown previous were likely psychological. The person coming in thinking like, okay, I need this type and I need to be eating and doing all this. And since I didn't, I'm going to perform less. And so self-fulfilling prophecy. If you believe you're going to perform less, you perform, you perform worse. So we decided to kind of try to control for that, to look at people who habitually follow these kind of patterns as well. Another kind of big aspect of those studies is they all used what we call time trials. So basically, and that's a best way to kind of mimic, you know, a race, because that's, uh, how fast, you know, an individual might be able to go from point A to point B. But Uh, that's not necessarily very representative of how someone's likely going to train. And especially if you're dealing with athletes, most of the time, I feel like they're not going to forget to eat on race day. So if they're going to forget to eat breakfast, it's likely going to be on a busy training day or looking at, you know, how, if you want to do carbohydrate periodization, you know, if they want to do some, some various training sessions fasted or something like that, but those ones aren't going to be You know, all out time trials, those are going to be your lighter sessions. So that's why for us, we tried to do something that actually mimics more of a typical training session instead of the, what you commonly see in literature of time trials or time to exhaustion, which is basically where we put someone at a certain intensity and just see how long they can go. Again, very interesting and very good for finding differences, but not very well representative of how people might actually train. And so how these dietary protocols might affect training. Um, and then when we did that, you know, we're still looking at all the aspects of it. Uh, but we, again, males and females, and these were pretty strong individuals. Um, so they had to be able to meet various strength criteria to get into the study. And this one, we also gave them all the food that we wanted them to eat.

Wow. That sign me up.

That was a good lot. If, if you liked Uncrustables, you know, we have a lot of Uncrustables.

So it really is real food.

And so, um, yeah. So for this one, uh, we provided all food and basically people ate the same exact amount of food. It was just either a breakfast and lunch and then come in and train in the afternoon or skip breakfast and eat the same amount of food at lunch and then come in and train. And so we were able to control that, um, a lot more than previous studies. And in that one, we didn't, um, find any difference, but it was likely again, because of more of that submaximal nature. So we were doing something that's going to be more well-representative of an actual training session. Now, um, that's not necessarily to say that, you know, it's never going to affect anything, cuz like we, mentioned with the diet before, those small changes in that might not quite be detectable at— with our current statistical methods in one session. If it's compounded session over session over session over session, might make a difference. So to truly see an effect, you'd have to do some of these longer-term training studies. And the longest training study that we have to date is 8 weeks with intermittent fasting. And so even then, that if you're looking at things like building muscle for hypertrophy and stuff like that, that's typically like the shortest amount of time you'd be able to see anything, like 6 to 8 weeks. And for improvements in things like VO2 max and all that kind of stuff for endurance athletes, you know, it could be even longer sometimes depending on the training status of the individual. Um, so that's not necessarily saying that, um, intermittent fast, like skipping breakfast, isn't going to impair it, but it's not going to— that directly is going to impair it either. So the way that I kind of sum up all the studies that I've done is you do you, you know. It's you— if you like— if this type of eating fits your style and fits your lifestyle and you enjoy doing it, then It shows that you can still do it as long as you're making sure and you're still eating the same amount of calories, protein, carbs, fats, that type of thing that we recommend. You can still do it and be successful. It's in, but don't feel like you're going to get an extra advantage by doing this. Cause so far the literature doesn't show that you get an extra fat loss advantage or anything like, or performance increase or anything like that when, um, diet is equated for.

I think this also goes to show that you have to stick with it, whether you're doing something for 8 weeks or 16 weeks or a year, or we can't just like snap our fingers and magically, haha, we're thinner. I mean, I'd be a trillionaire by now. It'd be really nice, right?

But yeah, that's, and that's one of the biggest things that, and that's one of the reasons I kind of actually like IF a lot is because I think out of All because we know pretty much all specialty diets out there work the same way by just by tricking you into eating less. And so with IF, you know, it's, there's a couple of reviews out there to suggest on average, when you tell people to eat this way, it gets people to inadvertently cut their calories by about 20%, which is a pretty good deficit. And because people will typically eat more when they first, that first meal when they start eating again, but this is not enough to make up all the calories that they would have missed, like at breakfast. And then. they kind of go back to normal eating patterns later in the day. And so they still end up eating less overall. And the thing that I kind of like about intermittent fasting is because like, uh, all it says is about when to eat, not what to eat, but there's nothing that says that, um, meal window, the feeding window has to be the exact same time every single day. So, you know, let's say you want to do, you know, the 16, 16 and 8, whatever. And then Monday through Friday, you know, you're at work most of the day. And so you want to put yours at like noon to 8:00 PM, because that still allows you, you can have lunch at work and then come home and have dinner with your family. Still have good, you know, nutrition guidelines around training, all that kind of stuff. And then, but you know, on Saturday comes up and you've got to go to a birthday party for your kids or something like that, that, you know, there's going to be food there. Well, you can still keep that 8-hour window. You just shift it up a little bit. And then, so now you can still have kind of that normal social life and you can just kind of move that window around a little bit.

I think that is interesting that you mentioned that, just because so many— I mean, we'll call this a diet, right? So many diets are seemingly restrictive in some way, and people can't really figure out the logistics of how to do something like this, right? So that's interesting that you sort of explained it that way, like, you know, you can be kind of flexible, and also you do you, right? Um, so, but it sounds to me like the main overarching theme is you're getting fewer calories. Like you said, you're sort of tricking yourself into, in essence, getting fewer calories. And if you stick with it long enough and you enjoy it, great. You're probably going to get results. Is that kind of what I'm hearing?

Yeah. And so like, we, we know the number one factor to long-term success is just adherence. And so it's finding something that allows people, allows you to stick to it, that you enjoy doing it. So. It's, you know, if, if you don't like fasting, it's fine. There are a billion other routes that you can go. That's why I know a lot of people, when I present kind of some of the literature showing like, oh yeah, here's the stuff showing that when you control for this, it doesn't really make a difference. Um, they go, oh, that, that kind of sucks. And the way I look at it is actually, I actually look at it as a very good thing because that means no one's being kind of pigeonholed or forced to do one thing. In order to kind of reach the goal that they're looking for. You have a bunch of different options, and this just shows that intermittent fasting is, is an option. It's just not your only option. So if intermittent fasting isn't for you, you can try one of the other, like, 12 million paths out there.

Yeah.

If you like intermittent fasting, it shows you can still do intermittent fasting and be successful.

So that begs the question, to me at least, of what were some of the things that people enjoyed about it from your subjects, and what were some of the common complaints?

Yeah, so the common things that some people like about it— and this is why I'd say typically I would only recommend someone do this when they're trying to lose weight. I get that question occasionally. I would never, you know, recommend something like this if someone's trying to put on weight because you're doing something that is making it harder to eat more. And which is kind of going against the goal of what you need to do to put on weight. But one of the benefits of it is if you are trying to lose weight, because you're able to have those meals closer together, typically you feel a little bit fuller during that eating window. Now, one thing to keep in mind when people start doing this, it's very common that you will feel very hungry You know, for the first couple of weeks throughout that fasting window, but that will typically go away like after like a week or two, people kind of adapt to that a bit. But yeah, the big thing is because you're putting all that same normal food, that same food fills you up a little bit more because it's in a shorter time period. Like if you have to, if you have to wait from 8 o'clock to noon and then, you know, noon to like 7. To eat, you're gonna be a lot hungrier in that intermediate time period versus if you're having those same meals at noon, 3, and, you know, 7 or something like that. Some of the complaints that I would see occasionally, uh, were people that had, you know, jobs where they'd bring in like bagels at work or something like that. It would be having to remember, it's like, ah, I can't really go over there and have that, the, the breakfast that the office supplied or something like that. Um, because it's during my fasting window.

So it sounds like more psychological challenges.

Yeah. So it's all of the complaints that people have found more the psychological aspect of it. And so that's where I say it's, you know, finding one that kind of like fits for you. So if you know that's an issue and you still want to do it, maybe moving your fasting window to something like 10 to 6. Or something. So you have an early dinner, but since it's, you start eating a little bit earlier, they, uh, you're able to still have like a late breakfast that some people at the office might not look at you funny for eating.

Yeah. Okay. So this is, this is super helpful. Uh, quick question about your research methods. So you had, you were watching these people work out, so they had breakfast. Then when was their workout in relation to their feeding times?

So that's, that's a good point. Um, pretty much all of the studies to date in terms of specifically looking at intermittent fasting, the exercise has been done within the feeding window. And that's what I would still kind of recommend is to try to exercise within the feeding window. Um, and depending on the type of workout you're doing, it'll impact it a bit more, but in general, just so that we can, you know, make sure you're following good peri-workout nutrition guidelines, Exercising within the feeding window is going to allow you to do that the best. Now, if the only time that you can fit it into your day is in the fasting window, that's fine. Just, uh, likely, uh, it's going to affect it less if the workout lasts less than an hour. And if the workout lasts more than an hour, it'll affect it a lot more. There's a really interesting meta-analysis, um, by Arden and colleagues that came out in 2018, kind of looking at that. Keep in mind that meta-analysis was only looking at aerobic training and found that working out fasted really was only impacted if it was over an hour.

In other words, their time to exhaustion was longer, or—

yeah, so it was things like, yeah, time to exhaust. They weren't able to go as long, or like RPE was higher. Perhaps RPE is typically higher. So that's another thing, just generally working out fasted in general, typically RPE will be a little bit higher. Um, so when most people work out fasted, if they're on an RPE-based program, they'll self-select a little bit lower intensity or slower speed because RPE will be artificially increased a little bit.

For those of you guys who don't know what RPE is, rating of perceived exertion, AKA how hard are you— how hard do you feel like you're going, right?

Yeah. So if, you know, someone tells you to go out for a run at like a 6 out of 10 or something like that. You know, that, um, 6 might feel a little bit higher if you were doing it fasted than if you've done it after breakfast. But again, those, most of that stuff again is acute. So if you're doing it consistently, it's likely that, that you get kind of like adapted to that and that wouldn't be as big of a deal.

Yeah.

Um, there's actually some versions of diet out there called under what we call carbohydrate periodization. That kind of actually will promote that. So you do your recovery sessions kind of fasted, but that's a big aspect of that is the fasted sessions that you're doing are your low intensity sessions to follow that. Um, cause I see that come up a lot with fasted training. People are like, oh, look at, look at this literature. Yes. Just remember that in that literature, what they're doing, the fasted training is all the low intensity recovery sessions, the actual like heavy, like tempo work, speed work, heavy intervals, all that stuff is still done in normal. Like fed conditions.

Good point. I'm glad that you brought that up. Cause I think so many people, especially in our endurance world, you know, oh, we got, we're going to burn more fat. So we have to do all our workouts fasted. And I encourage people to not do that, just like you recommended. Cause similarly, do you want to not feel great for your workouts? I feel like part of working out is to feel more confident and feel stronger and feel good about what you're doing rather than the opposite.

Yeah. And we have tons of literature to back that up, that people find the exercise more enjoyable, they're more likely to do it more. And so you want to do whatever you can dietary-wise to make that session feel more impactful, more enjoyable, all that kind of stuff. And, um, but that's, that's the biggest one that I run into with people talking about like fasted training and carbohydrate periodization. And the reason it potentially burns a little bit more fat is because it's at a lower intensity. And so the lower intensity, it burns more fat. Remember, just because it burns more fat doesn't necessarily— it burns more calories. And so the higher— what we see with that type of exercise all the time, especially fasted cardio and stuff like that, is yes, the calories you burn might slightly be a higher percentage of fat than carbohydrate. However, you burn so many calories less overall because the intensity is a lot lower that if you're doing that higher intensity work, Even though it's a lower percentage fat, it's still overall a ton more calories and overall still more fat, even though it's at a lower percentage. So doing what you can to still maximize performance within that training session is regardless of the macronutrient that's being burned for it is going to result in the better body composition outcomes.

Good point. Love that. So I always like to finish each episode with 2 or 3 takeaways that our listeners can absorb as it relates to diet, fasting, exercise. So let's hear them.

Yeah. So the biggest takeaway I would always say is, again, the most unscientific way I can sum up intermittent fasting is you do you. So if it works for you and it's something you like doing, the literature shows you can still be successful doing it, provided that you're making sure you're still getting the calorie intake that you want, protein intake, and carbohydrate intake. So endurance athletes, really make sure you're focusing on protein and carbohydrate intake because most people will eat less protein inadvertently when they start intermittent fasting. So start those meals off making sure you're getting the right amount of protein and then build everything else out around that. So if you like doing it, it's completely, it's completely fine. It's good. Go ahead and do it if it works for your lifestyle. Just keep that caveat in mind. Ideally, I would still say try to put the training session within the feeding window, but if you can't and it has to be, you know, just because the only time— because you've got family and kids and work and whatever— the only time you can get it in is, you know, right when you get up in the morning, that's fine. But if you're gonna do it fasted, just understand that especially initially it might feel like you're having to work a little bit harder for those workouts. But if you don't like doing it and you try it and you feel like, no, this just isn't for me, that's okay. Don't feel like you have to because it's going to make you lose more fat or make you a lot stronger or run or increase your endurance crazy amounts, because so far the literature just doesn't, doesn't show that. So just make sure that you're eating how you should. You can, just don't feel like you have to.

That's great.

Awesome.

Well, Dr. Stratton, yeah, thank you so much for joining us. Um, good luck in all of your endeavors and thanks for educating us.

Thanks.

I hope you enjoyed our episode today on intermittent fasting. And once again, if you're ready to equip yourself with the tools for sustainable, healthy nutrition tailored to your unique genetics and mindset, we'd love to have you join us. Again, this offer ends February 28th. Using the code GENETICS2025 for $200 off to get started today, head to theenduranceedge.com/longevity, and I cannot wait to see you there. Thanks again for listening. Thanks for listening to the Find Your Edge podcast. If you like what you heard, don't forget to subscribe on your favorite podcast platform so you never miss an episode. And if you're interested in learning more about our endurance coaching Sports and wellness nutrition, metabolic and sweat testing, triathlon training team, or our triathlon training library, be sure to check us out at theenduranceedge.com. And don't forget to follow us on social media at The Endurance Edge. Thanks again. And we'll catch you next time.