Welcome to the Empirical Cycling Podcast. I'm your host, Kolie Moore. Today, we are joined by Kyle Helson, and I want to thank everybody for listening. And if you are new here, please consider subscribing to the podcast if you like what you're hearing. And if you are a returning listener, which I assume most of you are, thank you so much for coming back. We love having you. And if you want to support the podcast because you're enjoying it, you can always give us a five-star rating wherever you listen to podcasts. That goes a long way. A nice review, a glowing review also goes a long way, too. Thanks so much for all of those. and a donation at empiricalcycling.com slash donate if you'd like to kick us a couple bucks because we are completely ad-free. And if you would like to reach out for coaching or consultation, please shoot me an email at empiricalcycling at gmail.com. It's currently mid-February, and if you are considering, well, you know, a lot of people have their coach for the year at this point. If you don't, you're considering it, please reach out. But if you are also self-coached and you want to get some feedback on your plan or get some suggestions, the consultation is the way to go for you. So reach out to me at empiricalcycling at gmail.com for that. And today, we are also going to do listener questions. So follow me on Instagram, Empirical Cycling, and check out the stories. Usually within 24, 48 hours before recording, I will put up a question box. It's purple for the podcasts, and I will specifically note it's for the podcast. But for the regular weekend, regular open kind of training Q&A, that's going to be over orange. And that happens every weekend, kind of come hell or high water. Although there was one time last fall, there was some high water and I didn't get to it. That is a Hurricane Helena reference. Anyway, because yes, I live in North Carolina now. So, all right. What are we doing here today? Today, I wanted to talk about some myths because there was a question came up on a forum recently that I read and I thought, oh, I've got a couple myths in my list of training myths and stuff that we can kind of put together for an episode. And so I wanted to get into myths about... kind of metabolism and substrate. And we've covered this a lot, especially in the Wastock series, but I wanted to kind of take a different view of that kind of stuff at this point. And also it's going to cross over with fueling. So stuff about fat oxidation, carboxidation, burning fats and carbs, and not really just the kind of adaptation that we get from burning fats and carbs. If there is any, we'll listen to the Wastock series on that because there's... There's really not. So we're not going to do too much deep diving into that today, if any, but we're going to really take a different view of this. And I also should note beforehand, I am also not a nutritionist or a dietician, and none of this is... constitutes even remotely close to medical advice. So if you are somebody who's interested in either like optimizing your fueling or if you're interested in losing weight and you want some advice for some of that, I highly suggest to reach out to a qualified nutritionist or dietician and specifically somebody who's got some cycling advice. And I know a couple, if you would like to reach out and ask me for recommendations, I'm happy to give you them. But anyway. Most of the stuff that we're going to talk about today is also part coaching knowledge because I've gone through many, many diets myself. I used to be about 20-something kilos heavier than I am now. Kilos, sorry. 20 kilos, good God. Man's ready for the stage. No, I was 20 kilos heavier than I am now. My lowest weight of recent memory has been 180 pounds. My highest weight in the last like four years has been like 225. Oh, wow. Yeah. So I am exactly one full bumper plate smaller than I used to be. So that's my experience. And I've also helped a bunch of people on fat loss diets who are my clients and our clients. I've also... helped with advice and guidance, but also with the caveat that I am not a nutritionist or dietitian or anything like that. And so this is all just kind of very generalized advice. And I'm also not a complete expert on the literature in this area. I've been diving into it a lot in the last like six months or so. And so I'm going to give my best representation of the scientific knowledge at this point, but also it's going to be colored with a lot of coaching experience with it. So there's my warning ahead of time. Kyle, do you have any other warnings that should probably be issued before we dig into this? No, I think you covered it. But yeah, I mean, I always think it's a sensitive topic. I always talk about food and diet and things like that. And so for some people, if this is something that you just don't want to listen to, no problem there. You can just skip it or something, come back for the next one. Yeah, please turn it off if this is going to be a sensitive topic for you because we are going to talk about body weight and fueling and energy deficits and metabolic adaptation and LEA and all sorts of stuff like that. So if, yeah, no problem if you want to skip this one, turn it on later or never again. We will see you at the next episode. So the first myth I really wanted to dig into today. is, I think, among our listeners, probably not that prevalent, but I think there's still one of those, it always kind of bears repeating things. So the myth is that you only need to replace carbs burned on your ride. Kyle, how often do you hear this? People who are like, oh, I'm just riding, you know, zone two or whatever. I'm mostly burning fats. How many carbs do I really need to burn? How often do you hear that one? I actually don't think I've heard it that often, but I feel like that it kind of goes into one, and we'll talk about this later, but it a little bit goes hand in hand with the idea of, oh, well, like, there's this optimal fat burning type thing, but I think that it's a strange, cycling is a strange one where Because you have a power meter, you can like know exactly how many calories or kilojoules of work that you did. And so you have a much more direct handle on the number where it's like if you're running or if you go on a hike or if you do swimming or things like that where it's much harder to figure out exactly how much work you did total and then back out. calories, and then be like, oh, I was in mostly fat because it was zone two, and therefore, you know, only 15% of the work I did was carbs or something like that, you know? Yeah, and even then, it's really influenced by what you're eating, how much you're eating, how much you have eaten, what are your glycogen stores, what are you eating on the bike, what did you have for breakfast, or did you not eat anything? that can certainly influence the substrate used and that's actually one of the things that we took, I don't know, what, 10 or 15 Wostok episodes to get into when we were doing the metabolism series. Yeah, we were getting to what are the actual signals for a roadback adaptation and are any of them related to the fuel usage? And the answer was categorically no. Which fuel you use is irrelevant for the muscular adaptations that you get. And in fact, as we're going to talk about today, you know, there's Well, let's put it this way. If you are going out for a long ride and you're like, man, I want to keep burning fats, I guess I'm just going to eat nothing but hazelnuts or something. I'm going to have nothing but peanut butter or cheese so I can keep my fat burning up. I mean, how much cheese could you realistically eat on... The amount of dry mouth I'm thinking about right now is pretty outrageous. Yeah. Oh, God. Yeah. So I think carbs... have a very practical place in ride fueling. And not just because what you burn doesn't matter, but because they're easy to absorb and digest, and they're plentiful, and they're affordable, and they keep well. I cannot imagine having a block of cheese in my pocket for like a five-hour ride in the summer. Like that's going to be absolutely disgusting by like minute 30. God. Can't imagine. Yeah. No thanks. Anyway, so. Kind of as you alluded to with the power meter and work output like kilojoules. Like kilojoules and Kcal, like a dietary calorie, can be roughly assumed as one-to-one. They're not really. But humans estimating us being about 20% efficient, we can kind of estimate it as one-to-one. It's not perfect. But when it comes to the body's energy accounting, that's also not perfect. If you know those folks who are like, if I have 10 calories more than I planned, like my whole day is ruined, or if I don't eat, I'm missing like 50 calories, like I'm screwed. It's pretty close. It's not that precise. And for people who are counting that hard, it's like, man. Do you know how much uncertainty already goes into the labels? When you're like, oh yeah, this one cup of pasta has 120 calories or whatever. It's like, well, that's also not like a, there are error bars on that number. That is not like a number to like eight decimal points after, you know, the zero type thing. Yeah, yeah, exactly. You're just lying to yourself, which is fine if that's, if, you know. If you want to lie to yourself, that's fine. Okay, but the body needs energy. The body is thinking energy. The body is accounting energy. I've said it 100,000 times in the podcast, and I'll say it 100,000 times more, which is that the body is an excellent energy accountant, especially when it comes to an energy deficit, where it's a little less fickle when it comes to an energy surplus, because in terms of our evolutionary history, what a great thing to have is an energy surplus. I cannot think of it. Anything better that would see us through tough famine times than like starting a famine pretty fat, you know? The body's going to love it. Like all those hibernating bears, you know? Exactly. Yeah, precisely. It's exactly their plan. Yeah, like nothing but salmon and honey for six months. Awesome. Let's do it. So the body, when it does its accounting, is not just going to go, oh, we need to replace glycogen. We're going to replace glycogen. Now, I wanted to actually start this out with an example of what happens if you actually do the accounting for just fat. Let's say you do a five-hour ride. We could hook somebody up to a metabolic cart and have them do this and feed them exactly the carbs burned, but let's just pretend that somebody does a five-hour ride. and they burn 3,500 kilojoules of fat. Or sorry, Kcal of fat. It'll be 3,500 kilojoules on the bike, roughly. And you've managed to eat back every carb you burned on the ride, which is going to be, you know, beyond 3,500 KJ on the bike, but we're going to pretend that those have now equaled out. You ate every carb you burned while you were riding and you're done. So now you are in 3,500 Kcal of fat debt. And 3,500 Kcal is roughly one pound of fat. Yeah. And so you just burned one pound of fat in five hours at a rate of 0.2 pounds per hour. And that sounds impressive. And I think if, you know, I think if... This were really the case thermodynamically, and you wanted to do that, what's the reductio ad absurdum argument? Is that the right phrase? I think so. Close enough. You know what I mean. Close enough. And you would say, all right, so if somebody burns off a pound like this and you only eat back your carbs, over the course of 20 rides like this, you are going to burn off 20 pounds. Is that what we see? The answer is absolutely not. Actually, if five rides like that, you could probably do that in a week, right? And are you down five pounds? I mean, you might be of like water weight and glycogen, but are you actually down five pounds of fat? And the answer is going to be probably not because your body's telling you, you need to eat more when you finish up with this ride. And if you don't... Eat back that 3,500 calories of fat, your body is going to be very, very, very grumpy. Or you're going to wake up in the middle of the night like ravenous, which I'm sure has happened to a lot of people. You had a long ride, you get back, you eat, but you're not going to like... continue, like, an extra 3,500 calories in a day is, like, you continuously eating for the remainder of the day, right? And everyone's had it, like, the next day you're like, oh my god, I woke up and I was starving, and it's like, yeah, because you were in, like, a 15, even if you ate a bunch, you were in, like, a, you could be in a 1,500 cal deficit, you know, for one day. No problem. Because I've been looking at this literature, I haven't seen, I don't know if it exists yet, any kind of measurements of the distribution of the maximal rate of calories that somebody can absorb per day. But the estimate is around two and a half to three times your BMR as kind of a ceiling for absorption. And so, you know, you can do a ride like this, and we'll talk about this in a little bit, either this episode or in future Wattstock, where you can actually eat. your face off on a day like this and like still be in an energy deficit when you go to bed. So I actually wanted to contrast our example right here. One pound of fat and 0.2 pounds an hour. Let's compare this to the general recommendations for a fat loss diet. So for a male of average body composition, so maybe 12 to 20% body fat. The recommended rate of weight loss that generally speaking is going to yield good amount of weight loss and not impact performance too much is about half a pound a week. Now, half a pound a week is 0.7 pounds per day or 0.003 pounds per hour. And that's... And that's, anybody who's dieted harder than that at a kind of average body composition, you will know that if you bump it up to like a pound a week or even go beyond a pound a week, you can actually get to the point where it's a really difficult diet. And dieting like that should not be difficult, especially if it's only like a, you know, kind of six to 12 week diet. There's absolutely no way. and I've certainly done this where I've looked at the scale too much and I've been like, but you know, I'm lifting weights, I'm kind of, you know, kind of doing a little kind of noob gains recomp and but I'm just like, you know, I want that scale number to go down and so I'll cut my calories even more and at week like six, I'm just like, is this over yet? Shoot me. Yeah, I've got six weeks to go. I'm not going to make it. I'm going to readjust. I'm just going to do another two weeks and just call it because I am miserable. And so that's what happens if the energy deficit gets too high. And so that's like going from 0.5 pounds a week to like a pound a week or something like that, or like, you know, two pounds a week even. If you're substantially over 200 pounds at a large enough body fat percentage, two pounds a week might be realistic, but that's a very special case, you know, it's not, it is not everyone. Yeah, if you're fairly obese, that can certainly be an easy thing to do. And actually, in a lot of ways, I haven't seen this literature myself, but I've heard from a reliable source that if you are of that body composition and you induce a fat loss diet, you start a caloric deficit, it actually turns out that that improves a lot of your markers for health instead of like testosterone goes up and stuff like that. Kyle, you and me, we start a diet and testosterone is probably going to go down. So there's a wide range of, yeah. And so like, let's say you're fine even at a pound a week, right? So we're going to say that would put you at 0.15 pounds a day or 0.006 pounds per hour, right? And that would be an even faster weight loss rate. And so now... Even, well, let's stick with the conservative number at half a pound per week. Comparing half a pound per week loss to one pound in five hours. It's like not even the same. No. And I did this calculation like five times because I couldn't believe the number I was getting, but I'm like, oh, it's just math. It works out. You know, comparing a half a pound a week loss to the rate at one pound in five hours. One pound of five hours is 66.6 times the rate of fat loss for, like, that you would average over a week. Yeah. Yeah, like, imagine, like, you could, you could, if this worked, you could just do this once a week. I mean, I guess, theoretically, maybe you could do that. Like, do one terrible day, and then a bunch, and then six normal days. Yeah. But it would be miserable. You'd be miserable for two or three days after your one terrible day. Right. Yeah. You'd be really miserable. And you would kind of equilibrate after like maybe four or five and you're like, oh, I got this shitty day going up. Here we go. Absolutely awful. My bank account, every time I get a paycheck, and my checking account balance goes way up, and then I pay all my bills, it comes immediately back down again. Yeah, well, I mean, if you get paid once a month like I do, I mean, that's exactly what it looks like. Yeah. And so, I mean, but my bank account isn't sitting there, like, telling me, like, hey, feed me. It's like, it's coming, don't worry about it. So, yeah, even, and if you go for, like, if you think, if, like, for you, a pound a week of fat loss is, like, a normal and acceptable rate. Like, now your five hours at one pound loss is, like, now it's double that weight loss, you know? Yeah. So... Yeah, and I think, too, it's like, yes, your body stores a lot of fat. Like, you know, you're probably not 2% body fat, and so... God help you if you are. Yeah, you might think like, oh, my body has plenty of fat, blah, blah, blah, but like, it's also like a very, your body doesn't like large disruptions from the mean like that, right? Yeah, and the way that I would put this is you are in an acute energy deficit because the body's thinking about energy and it's not thinking about substrates utilized. So, you know, the energy balance. I mean, this is why every single time you hear somebody giving nutrition or diet advice, they're talking about creating an energy deficit, not you got to burn fat. I mean, anybody who knows what they're talking about anyway. I've heard some people who, well, I won't name names, but I've heard some people be like, oh, this is how you burn more fat. And it's like cold water immersion or like do fasted cardio or all that kind of stuff. We all know that to not do that. We're looking at this at a more nuanced angle, but yeah, the energy balance matters the most. And the body actually has multiple systems to alert itself to energy balance, and it will change your behavior and regulate metabolic rates and stuff based on the magnitude of the acute deficit. I've actually seen a couple papers that lend some pretty good evidence to the idea that having a more frequent and acute deficit can actually lead to signs of low energy availability, like oligomenorrhea and stuff like that, or like low thyroid hormone, take your pick, and especially impaired performance. You know, and like, we're talking impaired performance the next day. It's not like if you keep doing this for a week or a month, you're going to have impaired performance eventually, or it'll slowly drop off. Like, there's a recent study came out, I think Louise Burke was on it, which is one of the reasons it was a good study, I think. And it's like, yeah, if you delay, you know, your post-ride meal by a couple hours, like, you're going to have... Impaired Performance the next day. It's not going to be, you know, it's not the difference between like you can do a 2x20 or you can't even start pedaling. It's not that bad, but it's a pretty stark number. It's a pretty impressive difference. So we're going to go into that in a future Wastock episode. So I don't want to get too far into it. But yeah, even, and I've even seen another study where over 24 hours, if the calories were adequate, People spending more time in like an hourly calculated deficit, that was also associated with significant signs of metabolic disturbance. I mean, startling, right? Yeah. I mean, I always think of, when I always think of these severe things, I think of the, maybe people have heard of the Minnesota starvation experiment. Oh, God. So bad. A study done in World War II, it was conscientious objectors who did not want to go. serve in the armed forces from the U.S. And so they volunteered. They got a bunch of men to volunteer to basically be starved over the course of like six months where they were doing like, they were eating like 1,500 calories a day and expected to also walk like 20 miles a week and also do other work. And scientists just tracked what their experience was like, which had to be pretty fucking brutal. Oh, I can't imagine. and so yeah you can look at that like yeah like it like all sorts of things are go wrong when you start when you start doing these things even even if you don't do it for six months even if you do it for you know month a month or something like that right like you're talking like these guys lost like you know a quarter of their body weight or something insane and you just you know all you can see all their ribs and all this stuff but yeah it's not good like yeah I remember yeah I remember reading that article and they would like go to the grocery store just to look at food Yeah, yeah, yeah. But, well, if people are wondering why, the reason was because they were, they wanted to, it was basically a refeed study where they had to check how much of what and yada yada were going to be best to feed to the people liberated from the concentration camps. Yeah. and so they were and also I remember that article distinctly because they also followed up with those people years later and they were all like yeah I would do it again no questions asked of course which I thought was really really cool but I will actually link it in the show notes because I think it's a really cool study and I may have done that already in a previous episode it rings a bell but I don't recall exactly so I'll link it in this one anyway and so if you haven't read it yet it's a good read So it was also, I can't think of the name of it. There was this, okay, so these were like, this was not a good idea. Just flashes up there, not a good idea. But there were these two, I want to say two or three guys, I think it was a British Antarctic expedition in like the 90s, I want to say, or late 80s, where they were like, we want to be the first group to traverse the Antarctic continent. entirely self-sustained. So that means like showing up and like cross-country skiing and starting with all of the food and water and supplies that you will have and trying to make it the, you know, 2,000, 3,000 kilometers depending on the exact direction that you take and they wanted to do it on their own. They did not make it, unsurprisingly. Good God. But like, it's because Obviously, you show up, and if you are expected to cross-country ski, dragging all of your own supplies, A, it's cold, so your metabolic rate goes up a lot, and B, you're doing like, you know, you may have to ski 20 miles a day, or whatever the average is, for, until you make it, and so they're, I remember seeing a documentary about this, and their projected calorie burn a day was like 12,000 calories, and they'd brought enough food. where each of them could average about 6,000 if they were to make it the whole time. Ooh. Needless to say, they got medevaced off the continent like a month in or something, you know, a month and a half in or something, you're like, oh God. Probably because they all lost 25% of their body weight. Exactly, yeah, yeah, yeah. Like, and so, you know, yes, you're not doing this repeatedly, but it's like, we have plenty of evidence to show that these sorts of things, if you think like, oh. It might be sustainable even in the short term. It's really not. It's really not sustainable. Yeah. And not only that, there was a paper published on a woman in the Tour de France, I think in 2023. And it was using doubly labeled water to measure total daily energy expenditure. And it was significantly higher than anybody really thought. And so we're going to dig into that in a future WASDOC episode because there's definitely a lot there. But the – actually, you know what? We're going to – let's put that on the back burner for a second because I just realized that I've got this in the notes for our third myth. So I want to actually tackle our second myth before we get too far off track. So we'll circle around back to that in just a couple minutes. By a couple minutes, I mean probably 10 or 20. So anyway. Thinking about losing a pound of fat on an endurance ride. And if your kind of sustainable rate is like half a pound a week, now you're at, what was it, like 66.6 times your recommended for those five hours. Or if your rate is like a pound a week, now you're at only half of that rate, but it's still like 33.3 times the rate of your recommended maximal. deficit as calculated hourly. So that's a big reason that burning more fat on your rides is not actually a good way to lose weight. And it partly comes from this whole thing of like, first of all, that's a lot, obviously, in just a couple hours, and you don't want to sustain that because of the accumulated energy deficit. But adipose tissue, your fat storage tissue, is an endocrine organ. Kyle, quick refresher, what's an endocrine organ? So it is like an organ that, you know, will have the ability to send and receive hormonal signals within your body. Like, you maybe think that your fat is just like a bank or something like that, where your cells just go in. Yeah, and make a withdrawal or make a deposit and nothing, and it is just like a passive storage thing and maybe that's like a nice convenient picture, but it's not. Like there are studies, right, where it's like even if you lose a bunch of weight, like the number of fat cells doesn't go, they don't go away, they just get emptied. and so especially in the acute term it's actually an open question as far as I know whether those cells actually disappear or not I would say based on what we're about to talk about and what I've seen with that they in theory should but yeah sorry please continue oh no it's just it's just not it's not as simple as oh I've got some fat stored and then I'm just gonna burn it off and it's fine that'll go away forever it's like no it it probably doesn't like It has longer-term impacts and is more of a give-and-take with the rest of your body than just being like, oh, it's a bank, and if I need extra calories, I just make withdrawals from this bank. Right. And so, Kyle, do you know the name of the big hormone associated with adipose tissue that was discovered in 1994, as recent as that? Oh, I probably learned it in college bio. It's called leptin. Leptin. Okay, yeah. For some reason, I could only think of like, I could think of ghrelin, and I could think of just like another hunger one. Yeah, ghrelin is made by like, I think, I know it's made by the stomach. I think it's also made by like the liver and maybe the one or two other organs around that area of the body. Yeah. Splankinic organs, let's put it that way. But leptin is the, hey, we're full molecule. Oh, okay. And so, you know, when you have eaten a lot, leptin levels will decrease. And when you are in an acute energy deficit, like you're dieting, your leptin levels will, you know, they'll be higher and, or sorry, they'll be lower. So there's a pretty wide range of individual response for leptin from what I've seen in the literature. actually seems to be quite well suppressed after accumulated energy deficits. And that would probably put ghrelin high up on the list, but I haven't really looked into that, so I'll just guess. I don't really know. Yeah, because ghrelin is the one that makes you feel hungry, right? So that's the one that like, oh, you're in a very large acute deficit. You're going to want to eat that whole large pizza when you get back. Yeah, and maybe it's just like an echo chamber of the area of the literature that I was reading. But it's all – I saw ghrelin mentioned very infrequently, and it was all more related to leptin, and maybe because of its recent discovery and its people going, oh, maybe this is the thing. If we can manipulate leptin, we can yada, yada, yada. But it's – so it's one of the hormones that's – kind of involved in the regulation of the body's energy state. And obviously the, you know, having high levels of leptin going, hey, we're full, like, for some people it works better. Some people it doesn't work that well. Just keep eating. I cannot blame them. Food is delicious. I get it. I love food. And so it's just one of many things. And at this point, potentially has, you know, well, there have been a lot of studies on leptin. It's a cool molecule. But there are other hormones. I was looking at one paper on ultrarunners, and they were looking at hormones like testosterone and IGF-1, which were also suppressed after accumulating a large energy deficit. And I also know that it wasn't in the same paper, but I had to go look. for it elsewhere, but thyroid hormone, also very sensitive to energy balance. And thyroid hormone affects kind of the basal metabolic rate of your body tissues. And like here's a good example is your heat generation capacity, right? So from what I understand, if my memory serves me correctly, I could be totally wrong on this, so apologies if I am, but thyroid hormone will affect the rate of uncoupling protein utilization for, it basically uses, it kind of decouples the mitochondrial protein gradient and how do we refill it? By using the Krebs cycle and how do we refill the Krebs cycle? By burning carbohydrates and fats. And so this is a way that we generate body heat. And if you've ever been on the tail end of a really aggressive diet, You know that you get very, very, very cold. Yeah. Even if it's 90 degrees in North Carolina, you can be very, very, very cold. And in fact, if this is for most sustainable kind of fat loss diets, you really don't ever want to get to this point. So if you are... Cold a lot. It could also be a function of just being very, very slim, which a lot of cyclists are, but you kind of want to differentiate like what's your normal level of cold and et cetera, et cetera. You may want to get a thyroid check. So anyway, all of that kind of stuff is related to your energy balance of the body. And all of that kind of stuff also seems to have a very strong impact on your rate of recovery. And this is more than just glycogen, because obviously glycogen is going to have an impact on your recovery as well. And so, you know, like that, like when Andy Coggin was on the podcast, he said a phrase that I hadn't really seen on the forums, which was, it's your glycogen budget, you spend it wisely. And this really... relates to people who are in an energy deficit. You're not eating a ton of carbohydrates, and so your body's using it. There's kind of a competition between your tissues that need carbohydrates, like muscles among them, and so your glycogen stores are never quite as full as they could be on a high-carbohydrate diet, and so you're just not quite as recovered and ready to perform, and so you've got to be careful with your super hard days. when you're in a state like this, trying to lose weight and whatnot. But more importantly, in an acute energy deficit, the recovery to your tissues is impaired. And like I said before, there's some good studies showing an acute energy deficit is going to impair metabolism in general. And that also means that you're going to impair your ability to recover from exercise and to perform exercise again. And so that's another reason that burning more fats on your ride doesn't necessarily mean losing weight because if you really just replace your carbohydrates, you are in a very, very, very steep deficit over the course of a couple hours. And that absolutely is a bad state to be in. Yeah. Evolutionarily, it makes some sense that your body would not just allow you to crater like this, where if your BMR stayed really, really high, even in deep deficits, you would starve faster. So kind of like, it's not a perfect example, but, you know, when bears hibernate, their metabolic rate goes way down so that they don't just evaporate in the first month, right? And they still come out looking haggard. Shredded, but haggard. Yeah, but that's the kind of example where, yes, humans do not hibernate, and yes, all of our closest ancestors probably did not hibernate either, but having the body having some ability to regulate BMR would be important for surviving during periods of feast and or famine. And it's important to also note that the body can only regulate BMR so much. Like it's not like you can take – Yeah, it's not – Yeah, you can't take a 1,900-calorie BMR, you know, that's like approximately me, you know, at 185-ish pounds. Like I will – I'm not going to ever have a BMR of like 100 and – you know, or like 1,200 kcal. unless I lose a significant amount of weight. You look like Christian Bale on The Machinist. Oh my god. I don't know how he did it. Didn't he have like an apple and a cigarette a day? I would assume heroic injections of Ozempic as well or something like that. Did they have it at that point? If they didn't... No, no, no. This was like 20 years ago. He was doing it the hard way, man. That is... That's more hardcore than the Minnesota starvation experiment. And so, yeah, scary. Anyway, so, yeah, burning fats on your rides as a weight loss tool is not, it's not a great way to consider it. And it's, because really just, you want to accumulate an energy deficit. and you don't want it to be a very large deficit and you don't want to accumulate a massive deficit in a short amount of time and then kind of get back to normal in a little while because it seems like that's just really not a good thing for your health or your performance. So that brings us to our third myth which is that your energy needs can be calculated by your BMR plus your bike kilojoules, approximating bike kilojoules to one bike kilojoule to one kcal. It's just a typical approximation. So this is where that study on the woman riding Tour de France comes into play. Because between this and two other studies I saw for men riding Tour de France and some classics using all doubly labeled water, Their metabolic expenditure was significantly greater than their BMR. Once you subtract out their bike kilojoules from their total daily energy expenditure. I mean, we're talking in the realm of 1.6 to 2 times their BMR, or even higher, depending on the nature of the race. Seems like the Tour de France is a little lower, like 1.6 to like 2 or something like that. And I think for the, like, classic, it was like one, if memory serves, it was like 1.8 to 2.3 times your BMR before you add in the bike kilojoules. So, massive energy. But keep in mind, too, like, BMR is how much, how many calories you'd need if you, like, laid in bed all day to not lose weight and you lay, you did nothing. Like, so. Oh, actually, I looked at a paper on that. And it turns out it's more than that. It's like 1.1 to 1.2 your calculated BMR. Yeah, because even using your brain to think about things burns calories. We've talked about this before. That's why if you're in a steep calorie deficit, you feel dumber because your brain really likes to burn glycogen. And really, really, when you're in a deep deficit, you don't have a lot of glycogen and you get dumber. temporarily. Yeah. Hopefully just temporarily. Hopefully temporarily. And so actually the paper on the woman racing the Tour de France, I'm going to link it to the show notes too, but if memory serves, she had approximately a 2,000 KKL deficit per day roughly. Basically she lost like two kilos over the course of like the seven or eight day tour. Yeah, it's a lot for – Yeah, and so using her BMR and using our approximation for maximal nutrient absorption as about three times BMR, like her fueling was about something like three times BMR, give or take. You know, the – well, usually it's 2.5 in the literature, but I'm going to err on the high side because I assume that the sport selects for people who have better absorption or is potentially trainable. I don't know. Does anybody? I also don't know. So it looked like it's possible that she couldn't have even eaten more. That's complete speculation on my part. But, you know, by the calculations, on average, she may have been eating about as much as she could have. It would have been nice if she could have eaten more, but also you're at the limit of like, what can the human... stuff in their face for, you know, the- Yeah. And like your stomach and intestines- Yeah. Only have a finite amount of surface area. It's not like you have, you can just like cram more food in and then magically have your intestines like absorb all these other things too. Like it's just, you know, yeah. Yeah. So, um, so that, so papers like that show the extreme side of What your energy needs are before you even calculate or account for the energy you spent on the bike. So obviously it's a sliding scale because if memory serves a paper looking at typical office workers is like 1.4 to 1.5 times BMR, people who have more sedentary jobs and like, you know, more sedentary home lives. so you're not walking around as much. All of this stuff costs energy. The more you move, the more energy you spend. And so those folks were at like 1.2, 1.3. I think I saw the high end was like 1.8 to 1.9. And that's total, all activities included with exercise and all that stuff. And once you become an endurance athlete, it seems like there's no data on this that I'm aware of. I actually did email one of the authors of one of these papers and suggested future research directions because I was like, I want to know what it's like. for somebody doing like eight hours a week, 15 hours a week, people who are not world-class cyclists. I want to see these energy numbers. I want to see what does this cost? What's your BMR multiplier for energy needs before you add in bike kilojoules? Because as far as I know, we don't know. We don't know what's the influence of intensity. We don't know what's the influence of volume. We don't know what's the influence of the extrathermic effect of food because You have to spend energy to digest the food, and it's not negligible, but it's not massive. It's also not nothing. So there's a lot of question marks around actual calculation of somebody's energy needs. And what we know from Herman Ponser's work on the constrained energy expenditure hypothesis, it actually seems like a special case. And we'll go into this in a lot more detail in a future Wastlack episode. But for now, it seems like a special case where if your energy needs kind of go up a little bit, your body will adjust. It'll potentially reduce your BMR and your rate of metabolic processes and stuff a little bit. It'll probably keep you from moving around. And that seems like it might be a larger effect. I'm not really sure. So like your neat non-exercise activity thermogenesis, fidgeting, walking around, playing with the kids. Like, you know when you're in an acute energy deficit and you're like, I gotta get up and, I don't know, take the cookies out of the oven. But you're gonna sit there for five minutes and listen to the oven alarm timer go off and you're like, oh, I'm burning them, aren't I? I should get up. That is the kind of... behavioral change that being in an acute energy deficit can actually make. And so once you actually get beyond a certain amount of activity, it seems like it becomes more additive again rather than constrained. And this is all just me speculating on what I've seen in literature. I could be totally wrong. I could be misrepresenting something without knowing it, and I apologize if I am. But that's what it looks like to me, at least at the moment. And so, yeah, your BMR plus your bike kilojoules does not actually equal your energy needs. And in fact, your BMR calculator – oh, by the way, Kyle, do you know where the 2,000-calorie daily needs things comes from? Oh, like the FDA typical average? I thought it was like, you know, an average like 170 pound male or something like that. No. So it actually comes from self-reported food diaries. and people are notoriously bad at estimating how much they eat. Yes, definitely. And so it's actually, it should be more like 25 to 2800 kcal per day as like the average size person's energy needs. That's what it actually is. And so, because energy diaries or food diaries. will typically underreport by like 30%. And I've seen some data suggesting it's the list like 10 or 20% or maybe a little less, something like 10% for like registered dietitians. You know, that's like, you know, that's like the Pope of dietitians. That's as high as you can go. But for average folks like us, we are horrible, horrible at estimating how much we're actually eating. that's where that came from and that's I think one of the many reasons that a lot of people think their energy needs are actually not as great as they are so like if you've got a very active lifestyle you probably need more food and so if you are in doubt of any of this reach out to a nutritionist reach out to a registered dietitian somebody preferably with experience with cycling or extreme endurance sports who is aware of the actual energy needs because I've actually seen Again, I don't want to name names, but I've seen some cycling nutritionists who vastly underestimate what somebody actually needs. And in fact, a lot of the apps out there that I've seen will vastly underestimate somebody's energy needs. And it's to the point where it's genuinely concerning for me, where I think that a lot of people are Hiring their performance and potentially their health by following these apps that don't really understand how much energy a cyclist actually needs, especially when they're training a lot and training really hard. Sorry, not a nice note to end that on, but any other thoughts before we move on to listener questions? No, I think the other thing is that One thing too, people will pull up calculators a lot too online. They think, oh, how many calories do I have to, what are my target calories if I want to lose weight? All of those things are typically done on population average type things. And so if you're someone who happens to have more muscle mass than average for your given height, weight, age, like that calculator is going to be off and it's going to underestimate because just having more muscle means that your BMR is going to be higher than if you are someone who has the same weight. But, like, doesn't have as much muscle. So, you know, again, we've talked about things like this on other episodes where a lot of these handy rules of thumb or equations or things that have been fit, they've been fit to these, like, population averages, and so there's lots of scatter within there. So it's close. It'll get you within the ballpark, but certainly... Even for the bigger diet companies and things like that, they have you track calories, track macros, whatever, and then they have you check in in a week or two weeks or three weeks and see actually what does it look like? Are you losing too fast? Which is a thing. Are you losing not fast enough? Also a thing. And adjust calories from there. You should be able to do check-ins and have regular feedback. Just like with training plans, it's not just like, well, cut and paste, here you go. See you in 12 weeks, you know? Yeah, for sure. And this is why I've seen some really good nutritionists at work and, you know, people like Namrita, who's been on the podcast. And, you know, if somebody says, oh, I'm really hungry, but I'm eating all the calories. What does she say? Eat. Eat more. If you're hungry, eat more, especially if you're not trying to lose weight. And there's also that kind of, I don't want to call it a vibe check. It's like a symptom check. Are you experiencing any of these symptoms of a severe deficit? where your concentration is bad. You're really grumpy. You're experiencing sexual dysfunction. You are experiencing being very cold. You are experiencing constant thoughts about food or any of those kinds of things. Those are signs that it's too much and the body is an extra energy accountant and we all kind of suck at it. So if you do experience these symptoms, You just got to make sure to eat a little bit and kind of get a sense of what a regular deficit should feel like if that's what you're trying to induce. And if you are not trying to be in a deficit, then you should not be experiencing any of those symptoms. I mean, sure, they can happen even if you eat 120 grams an hour on a long ride, but that's something that you've got to account for in your total training plan also. Give yourself a couple days to... Eat back your calories and recover fully, et cetera, et cetera. So does all that make sense? Yeah, hopefully that is at least a little primer on some of this stuff. I know these things are always, it can be a little bit confusing, especially given popular media diet culture and all these things that are just, God, so cringy at best. dangerous and scary at worst. People say a lot of weird things and have a lot of weird opinions about food and diet, and I think it can be really dangerous, especially if you're someone who's, you're not just living a sedentary lifestyle, you're going out and you are doing a lot of very intentional work, and that is definitely, you know, just amplifies your risk that something bad happens. Yeah, and actually, it's like, oh, sorry, go ahead. Oh, there's this hilarious diet from, oh, it was published in, it was published in Vogue in like the 70s or something. It was like, how to lose like five pounds in a weekend. And it's like, it's basically hard-boiled eggs, black coffee, wine, and that's it. It's basically just like, eat like six hard-boiled eggs a day. have up to one bottle of wine and as much black coffee as you want. It's like the 1900 supermodel diet or something. And you get like a steak for dinner. You get a steak, you can have like a four ounce steak for dinner. Oh, a four ounce? Yeah. Yeah. Well. It's not good. It's not good. No. But if you Google like the egg, wine, and like. Coffee Diet or whatever. It's hilarious. There's definitely a blog post of someone who tried it for a weekend and didn't even make it through. Imagine three straight days of six eggs and four ounces of steak a day. That's like a meal for me. I don't even remember. Right, exactly. And then a pile of rice, yeah. Well, I was actually just thinking that back when I was doing carpentry, I mean, they're pretty active, brutal, like seven, eight-hour days. and it's a lot of up and down. You're basically moving pretty constantly and the times that you're not moving, it's such a relief. And then I was training on top of that too at one point. And I remember if I, I would always kind of drag in the afternoon. I just kind of sucked in the afternoon. I was just not there. I was not fully full gas despite having a good lunch or what I thought was enough lunch. And I remember one point, brought like twice as much food for lunch one day because I thought that I don't know why I was going to like leave it there at the job site for the next day or whatever. There was a fridge there. And I ate it all that day. And I had so much energy after lunch. For the first time ever, I was not dragging ass. And I was like, Oh my God, I ate more. I ate enough apparently. And now I feel great. And so ever since then, I was like, I would eat way more than felt like was necessary at lunch. And I would always have a really good afternoon of work. And that's like kind of the symptom check that you can use. It's like, how much energy do I feel like I have? And I was probably like, you know. like 1.7 to 2 times BMR for my activity level before I started cycling. And then of course it was like, what, you know, adding in bike kilojoules, I couldn't even calculate. Yeah, another 800,000 to 200 calories a day, you know, yeah, whatever. Yeah, and not training every day, but like the energy needs were absolutely insane. And so, you know, I just distinctly remember that that first day made such a lasting impression on me of just finally eating enough, feeling what that was like. And in fact, you're in-ride fueling. Like if you're not eating enough on your rides in order to, like I've had a couple clients who've got like a, try to, like a continuous glucose monitors, try to kind of see what it's all about and see, it's got fueling recommendations or anything like that. And I remember one guy saying that he's got a threshold of high 200s, like 270, 280, something like that. And I remember him saying one day, he was like, my blood glucose tanks if I'm not eating at least 70 grams of carbs an hour at endurance pace. That's a lot. Yeah. And that's actually in line with a lot of the more current fueling recommendations that I've heard for people who've got thresholds in that range. It's like at your endurance pace, you want to be eating 70, 80 grams of carbs an hour. And then as the intensity increases, you want more than that. And so this is not a recommendation. This is just what I've heard, but it seems to work really well. And that's kind of based on... energy needs and energy expenditure because there's more happening in your body in terms of metabolism than just what goes into the pedals. Like your total body metabolism, it's, yeah, it changes. It's higher than you would think because there's more processes that go on to support exercise. Like your whole body's systems change, you know? It's not like, oh, just my legs are moving, my heart rate's a little higher and that's that. Like it's actually way, way more involved. Yeah, I think the other thing too is like, if you use a step counter, for example, and I have one just because I think it's kind of fun. You can see how much you walk, stuff like that. But like, you can imagine that if, you know, one step of walking, getting up from your desk to go to the bathroom and come back is not the same as one step if you are carrying a sheet of plywood. You know, like these, so even with that where you think, oh, I'm getting better, I'm getting closer because I'm using a step counter and all these things. It's still, it's better, but it's still not, you know, awesome. Yeah, it's like not all TSS is created equal. Exactly, yeah, yeah, yeah. And so, yeah, all of these things can help get closer, but, you know, you have to be a little honest with yourself. Yeah, very, very true. And having carried many sheets of plywood in my day, I can confirm that it's much, much harder, especially if you're going upstairs. Like, one step on flat ground is very different than going upstairs with a sheet of plywood. Okay, cool. So listener questions. What do we got for listener questions today? Thank you everybody for submitting at Empirical Cycling on Instagram. Let's see. How is the sugar used during exercise? Does it replenish muscle glycogen or get used first? Actually, according to all the current data that I've seen, your best bet to improve muscle glycogen sparing is to train more. The fueling that you have does not seem to really change the rate at which your body uses muscle glycogen. So when you eat carbohydrates, it goes to supporting your blood sugar, your blood glucose, and that spares liver glycogen because if the liver sees that blood glucose is high, it's going to be like, cool, we don't have to do anything. and then when it makes it to your muscles, it's going to oxidize it and it can and does do that in place of fat but the fat carbohydrate is a question of availability and it's not necessarily sparing muscle glycogen. So that is kind of the lowdown on what happens to the sugar that you eat and not only that, if you want to think more holistically, if we want to think about energy balance, you are maintaining a smaller energy deficit. And depending on how hard you're riding, for somebody like me, I'll ride at like, you know, 80 to 150 watts for like two, three hours, and that'll be my ride, and 150 watts is a lot harder than 80, obviously, at my, you know, 200-ish watt threshold. But, you know, I will, at 80 watts, I'm not going to need 120 grams an hour, but at 150 watts, I will probably need, you know, Much more. And so at low power outputs, you can easily out-eat what you kind of spend on the bike. But for most people, yeah, it's kind of difficult to actually eat what you're spending on the bike. And most people will finish rides in a deficit, even if you eat a lot. I think the other thing is like the, you know, as things, at least on-ride nutrition has gotten better, things are, more palatable, so it's easier to eat those things too. Think about if you didn't have sugary drink beverages and stuff, you could just throw a couple scoops in a bottle and all of a sudden you could have almost 300 calories just in a bottle. So yeah, but I think if people are worried, I worry that people are worried that if they're trying to ride and lose weight, they're like, Oh, I can't have anything because then I'm like defeating the purpose. I just don't want people to do that, you know? Because like if you think about it, yeah, you're right. It's not so hard to burn 300 calories to replace, you know, a couple bottles of sports drink or whatever. Or a donut. A donut, yeah. Yeah. So don't do that. Don't be like, oh no, I have to get this calorie burn and I can't have any food. Yeah. And so I think actually it would be interesting to think about as an example, what happens if you are trying to lose fat and you're not exercising at all? It seems somehow I think for cyclists it would seem more intuitive that like it doesn't matter what you are eating as long as you induce an energy deficit, it's going to, your body's going to like take that energy. in a slow manner from your fat stores and use it like that. And so once we add cycling and we start thinking about adaptation, once again, the fuel substrate that you use is not related to your adaptation. It is the later consequences you have of burning more fat at the same relative exercise intensity is a consequence of training. and that's as best as I understand it right now according to all the data that I've seen and I've looked at quite a lot of papers on this. So next question is, why am I fat? I don't know, why am I, dude? I can't lose weight even when counting calories. So this kind of goes back to what we were talking about earlier is that people are actually really bad at Estimating how much they're actually eating. Because most people of any size who have said, like, I'm eating 1,200 calories a day and I can't lose weight. Most likely you're not actually eating 1,200 calories unless something is really, really wrong. So, you know, and once we start considering... the behavioral and metabolic adaptation that can come into play and people tending to, and I'm no different by the way, people tending to way underestimate how much they're eating, you can easily think you're in a deficit and not lose weight. On the other hand, if you're doing like a crash diet and your deficit is way too high and you're expecting it to move very rapidly, or if you're even thinking in the course of like two or three weeks, Typically, if you're losing like a half a pound to a pound a week, you know, your water weight fluctuations day to day can be like, depending on your size, it can be like two, three, four, even five pounds. And if you're like a huge bodybuilder, it can be even bigger than that. Not to mention, you know, if you are eating less weight, then you're also probably, you're going to be, you're going to be maybe going to the bathroom less often, and so you'll probably also have that to contend with as well in terms of just day-to-day, your scale weight. If you're just directly comparing one day to the next, the fluctuations are totally going to swamp. I think that's called a residue or residual of your diets, just to kind of how much is in your gut digestive tract at any one time. I don't totally understand that, so I won't comment on any of the mechanics further. But another thing that can happen is especially if you're in a really acute energy deficit and your body is stressing really hard, that can actually lead to water retention. That's my understanding anyway. That's what I've heard from the bodybuilding world. So assuming that those folks are correct, there may also be a factor of special sports supplements involved in this. I don't really know. But it seems like if you are retaining water from being super highly stressed from having an energy deficit that's really acute. That could also lead to the scale kind of being the same. So you want to make sure that you're tracking a deficit by multiple sources of like, what do I look like? Although hydration can impact what you look like a lot. What does the scale say? Like, am I categorically in a deficit? Like, do I get signs that I'm in a deficit? Do I get groggy? Am I hungry? All that kind of stuff. So especially also if you were lifting weights like you should be while you are trying to lose weight, you can actually put on muscle, especially for noob gains, you can put on muscle while you are losing fat at the same time and that can make the scale kind of be the same and depending on like I'm experiencing right now, started doing upper body strength training for the first time like ever, I'm in a deficit and I'm actually gaining weight, which is really, really weird. But I am categorically in a deficit and I am categorically gaining weight. Noob gains are really fun. So I have lots for the first time in my entire life. But at the cost of the scale going up, but my body fat percentage going down. So yeah, there's a lot of reasons that... Anyway, that's kind of not what we were kind of thinking about with this podcast. But anyway, I didn't mean for this to turn into like a... diet tutorial. Let's see. Next question is going to be, is it true that fat cells never go away, they just shrink? So here's why it seems to me they might go away. I have never heard anything or seen any data that is conclusive. And when I hear experts discuss the matter, they all... seem to say that nobody really knows. Some people are of one opinion, some people are of another. So this is my interpretation of one data point, is that when you look at people who have lost weight, and you look at their subsequent leptin levels, their leptin levels seem to track for what would be expected if you control for their loss of adipose tissue. And so if those fat cells stuck around, you would probably expect or I would expect that leptin levels would remain higher than expected. But once you adjust for it and you see the leptin levels go down, it seems to me that they must go away. But that is absolutely not any kind of definitive proof. So thoughts, Kyle? Yeah, I think it's just hard to measure. You imagine you want to have to biopsy people and take stains. And the problem is the cells, they do at least get very, very small once they don't have fat inside of them. So then seeing them is hard and counting them is hard. I don't think there's a good direct measurement that we can do. Yeah, and you could easily make the argument that an empty fat cell... could potentially not have the energy in it to create leptin. So like I said, you could easily make the argument that they're still around and just inactive in some way. I don't know that we'll ever really have a true answer, although I think, yeah, I don't know. I just don't. Okay, next question is, does fat oxidation mean that your body is burning the flab you see or something else? So yes and no. The fat that you oxidize can come from a couple places. The obvious one is that it comes from your adipose tissue. It's liberated from your triglycerides. So the ACL group is what connects the fat molecule to the glycerol molecule. And glycerol gets liberated in the bloodstream, and you can see blah, blah, blah. And the fat also travels. We've done this in the podcast before, so go check out Wattstock. I don't know. 40, no, it was like 30-something, talking about fat oxidation. And I think we had a couple actually had fat oxidation and like the travel, the journey that the fat molecule will go through once it gets liberated from your fat tissue. That happens. It also happens that your muscles have what are called intramuscular triglycerides. And you'll see that abbreviated in papers as IMTG. Those also get liberated from their little droplets, but they don't have as far of a journey to go through. And that seems to make a difference. I mean, otherwise evolution wouldn't have decided to store fats in our muscles directly. So that happens. And we could also oxidize dietary fats. So that's really just a question of how much fat have you had? How much is digesting in the last, I don't know how long, what, 12, 24, 36 hours? I don't really know. how long that kind of – that should be pretty basic. I don't know it. Sorry. Yeah. I would say also the – your body, when you're in a deficit, you're just going to burn fat generally. And so that also is not – it's not like you're just exercising and that's the only time you're burning fat. So just existing, sitting on the couch, watching TV, whatever, your body can be taking fat from all these different places and burning it as well. Yeah. And also – actually, well, having – mentioned that. We should make a distinction between the way that the body handles substrate oxidation at exercise versus at rest because they are two quite different things. So we've got the rest and digest and then the fight or flight kind of stuff. But yes, at rest, well, it kind of depends on what you've been eating actually. Anyway, next question is... Has the kilojoules spent equals Kcal burned thing has been studied? Does it actually hold true? Yeah, it has actually been studied quite a bit. Kyle, there is a physics equivalent of kilojoules and Kcal. Do you remember the exact equivalence? What do you mean the physics equivalence of kilojoules and Kcal? So there's a conversion factor. Oh, yeah. Kilojoule is, I don't know, it's what, it's four-ish, it's four point something, it's like four point two, I don't know. Four point one, two, six, maybe, pretty close, we just call it four. Yeah, I always say four, because I, I don't know, pie is three, right? That's why. Pie is three, yes. I'll have three pies, please. Yeah, and people are on average about 20% efficient. But as exercise intensity changes, efficiency changes. And so you can start to estimate approximately how efficient you are based on your exercise intensity. I personally find all of that to be a little – like if you – well, if you don't have any direct measurements, you've got to make some assumptions. And that's always – One of the things that can get you in trouble, even if you have direct measurements, my understanding is that you can still have to make some assumptions on, you know, all the other fuzziness that goes into energy expenditure, because you can have metabolic adaptation, you can have behavioral adaptation, you can have, you know, your immune system can be highly active, which is going to increase your energy needs. And so the energy accounting is really difficult to actually do. estimations that you have to make when you do like doubly labeled water studies. Well, according to what I read, I don't fully entirely understand exactly how all that works, but I have read the limitations sections of several papers on the estimates that have been used, and it seems to be that they're pretty small. So it seems like a pretty robust method of measuring energy expenditure. However, when it comes to Really estimating it without that kind of stuff, it's very, very difficult. So I don't necessarily think that getting too nitty-gritty and precise with any calculation of energy expenditure or efficiency or anything like that, I don't think that that realistically gets us anywhere useful. I am totally open to having my mind changed on that, but as far as I understand it right now, that's where I'm at. I know some nutritionists. and dieticians who do do stuff like that and they seem to be very successful. So maybe they're just smarter than me at this and they're definitely more educated. So I will defer to them. So as always, I suggest consulting with somebody smarter than me on this kind of stuff. But yeah, it has been studied into the ground. The kilojoules equals Kcal thing, it's close enough. 

Oh, here's a good one. Next question. Is FatMax training or is the FatMax or that training ideology valuable for long events like Ultra or is regular aerobic training still king? You know, I've changed my tune in this a little bit. I remember saying in the podcast a couple years ago that I thought that Ultras are the one place where it would make sense to do keto, but I was at the time mostly thinking about fueling logistics and fueling needs. So like if you are going to go out for a 36-hour bike race, carrying that much fuel with you is a pain in the ass. So if you can carry less and be burning more fat, seems like that'd be advantageous, right? But based on everything we discussed today, which I've learned over the last couple years, it seems to me that even if you can burn endogenous fat stores for that acute bout of exercise, it seems to me that, especially if you do that a lot, it would probably be detrimental to recovery and performance and health. And so the time that it takes to get to that state... plus the race. I'm not sure at this point it would realistically be worth it. I know that there are several athletes who make that worthwhile. However, I think in the cycling world, having seen the eat more carbs, do more work, get more faster kind of thing that we've seen in the last like five, eight years, I think that that I would like to see kind of permeate the ultra world and see if that helps a lot. Because I know that the couple ultra runners that I follow are very, very, very much into carbohydrates. And so it seems to me that in terms of that kind of thing, I know this wasn't really the question, but this is where I wanted the question to go. So it seems like that kind of thing would probably be, yeah, at this point, I'm more like, you should probably just eat all the carbs. Because as we've said a million times, you know fat max training does not actually train you to burn more fats burning more fast does make you better at burning more fats training all training makes you better at burning more fats and eating more carbs and recovering faster and having that smaller acute energy deficit seems to really really really help recovery and performance especially like even if even just in a regular training week it seems to help massively so Kyle thoughts there or shall we move on Oh, that sounds great. Cool. I like carbs. Who doesn't like carbs? The bagel place just down the road, down on the block. For me, it's great. I think Liver King doesn't like carbs. Fuck that guy. Let's see. How do you balance the need for more than just carbs and ultras when you still need to be hitting 100 grams of carbs an hour? Okay, so this is really kind of beyond the scope of the podcast, but I want to answer it anyway. It seems like... So getting in some protein and some fats really, really helps because especially with just general feeling, but also in terms of performance, it seems to help folks where if you're just eating carbs on like a, let's say an eight-hour race, a lot of people will kind of be like, I ate enough, but I feel hungry, that kind of thing. But having a little bit of fats and a little bit of protein can actually go a long way towards not only feeling satiated, but also especially for multi-day events. It can really, really go a long way to just providing your basic needs because you need a little bit of fats and you need protein in order to continue your regular ass metabolism. Yeah. There was a, oh God, it was 20 years ago now when that four to one protein carb thing started becoming really popular and even had Accelerate had that. It was intra. sports drink and had a little bit of protein in it. It definitely seemed like it was a fad and they were trying to get by. Oh, you mean 41 carbs to protein? Yeah. They were selling intra-activity drink mix that had some protein in it. Oh, I think I tried that in 2012 or 13 or something like that. I remembered that if you left the bottle too long and didn't wash it, it would... Go Rancid like Rotten Meat would go rancid. Oh, yeah, immediately. Oh, yeah. Nasty stuff. But anyway, that's my understanding just kind of based on my understanding of the body's energy accounting. And I'm sure, I'm absolutely certain that there's some nutritionists out there who's screaming at me right now, like, this is wrong. It's this, this, this. Like, you either need a lot more or you don't need quite as much or there's actual numbers associated with it that work for most people. There's something like that out there. I don't know what it is. Eventually, I'll talk to somebody on the podcast about it for Nutrition for Ultras because I'm actually quite fascinated by it. Okay, let's see. Okay, here we go. Timing don't matter. All about energy balance at the end of the day. So I'm going to refer you back to what we said probably in... hour, 45 minutes ago, where we were talking about a paper that was looking at energy deficit as the people who spent more total hours in the day in an energy deficit seemed to have more signs of metabolic disturbance. And also the other one, which we will definitely be getting into in a Wattstock soon, about how delaying feeding after acute exercise. Impaired Performance the next day. So it seems like that it actually does matter quite a bit. And if you are one of our clients, I sent out a monthly email. I've already sent out an email about this kind of thing a couple of months ago. So you will already be thinking like, this is old news if you're one of our clients. And so if that's you, well, that's awesome. And hell yeah, you're ahead of the curve. Yeah, I mean, I would say just one thing is like, definitely don't Stress out like, oh, I had my post-workout meal 37 minutes after instead of 30. Like, don't freak out at that level. But like, don't be like, oh, it's been like four hours since I got done working out and I haven't eaten a single thing. You know, like, if you're stressing your friends out because you're like, oh, I have to eat, I have to eat or whatever, then like, you know, like. Don't be that person, but don't just think that it doesn't matter at all. Somewhere between these two extremes is probably the right approach for a lot of people. If you've got to finish a ride and then get right to something and you can't eat as much as you want to and you're just shoving protein bars in your face and a granola bar or two in your face as you run out the door, that's okay if it happens once in a while. We're talking if it happens regularly. That's where it can really start to potentially be a more severe impairment. Okay. How to estimate substrate usage. It's very difficult to actually do that. Buy a metabolic cart. Yeah, buy a metabolic cart. And even then, the... results you get from the metabolic cart are also going to depend on what you've had to eat and it's going to depend on the protocol and how fast you ramp and how much warm-up you've had and kind of stuff like that. So it's notorious. Just do it once a week. Can you imagine running around with like a backpack on all the time with a mask on your face? Sounds terrible. I mean. Extra training, I guess. Resistance. Yeah. Next question. Because I guess some people have not listened to the entire back catalog. So if you're new here, this probably bears repeating. We've said it before. But does consuming sugar on an endurance ride change the fat-burning adaptation? The answer is no. And to rehash a little bit of one of the previous Watt stocks, that would actually make a really bad system. You were like an early hunter-gatherer or even a modern hunter-gatherer, why not? And you have abundant carbohydrate sources, but you have to do a lot of walking or jogging or running to get to them. And you've got not a lot of protein sources or fat sources. It would be a bad system to not be able to adapt to endurance exercise just because you've got abundant carbohydrates around, and that's the majority of what you eat. And the opposite also is true, where if you have abundant protein and fat sources and not so much carbohydrates, and you have to lift a lot of heavy things or you've got to like wrestle bears a lot or whatever would require you kind of being swole and sprinty, you know, same thing on the other side. So it would be a bad system if it worked like that, but luckily the signals for endurance adaptation rely more on things like is the muscle contracting, presence of calcium, elevated calcium for... durations of time. What is the redox demand? Like how much flux are we getting through the electron transport chain? How much energy demand is there in the cytosol? Like AMPK. How much cellular stress is there? MAPK. Like these kinds of signals are what actually point at the endurance adaptation. And so this is one of the other reasons that we're seeing people eat a fuck ton of carbohydrates these days at the world tour and get even faster than ever. So I think that is... It could explain quite a lot of why the modern Peloton is so much faster than it was like 10 years ago. The Froome days of like not eating. Do you remember those days? Yes, yes I do. 10, 12 years ago when like, oh, you can do, it's amazing what the body can do on so little and you're like, oh God, oh no. Yeah. Oh, we've come a long way since then. Let's see. Is there such thing as too much carbs? Actually, yes, there is such thing as too much carbs. So I'm not an expert on this myself, but it turns out that if you have way too many carbs at rest and you don't need them, that could be a bad thing. Yeah, you also do need... fat and protein in your diet just to be healthy even if you're not undertaking a lot of exercise. And even then, like, you can't – it is not a good idea to be like, oh, I'm trying to lose fat and I have a bunch of fat stores. I'm just going to zero out the amount of fat I eat a day. You're very unhappy. Yeah. Well, oh, that – So if you were eating too many carbs in the expense of fats and protein, then yes, that would also be – Yeah. Like, I think you'd have to go very far out of your way to get – less than like 20 grams of fats a day. And actually, there's very little research on what is the minimum required fats. Like we've got estimations for like carbohydrates and we've got a ton on protein, tons and tons and tons on protein. Not a ton on protein for endurance athletes, but lots of protein for strength athletes and like, you know, body composition kind of stuff. But generally speaking, What the hell? I'll put this in the show notes too. There's only one article that I've ever seen. It's by Eric Trexler on minimum fat needs in a diet. And it's like, you need like 10 grams or something like that to prevent gallstones. And then you need a certain amount above that to support this. And you need a certain amount above that to support production of sex hormones. You need a certain amount above that to produce whatever. You know, he comes to a conclusion, but I'll let people read that for themselves. Yeah. Also just like joints and things, your joints need fat, your brain needs fat. Yeah. Yeah. So, you know, there seems to be a good, you know, as long as you're getting enough fats and proteins in your diet, pretty much the rest can come from carbs. But like, yeah, it's like I've done this myself. It was difficult, but usually when writing less. But like you can definitely. Eat Enough While You Are Training a Decent Amount, and Gain Weight. It can certainly happen. You've got to work at it, and you've got to really love food. And I worked at it, and I love food. So I made it happen. So it can be a thing, for sure. But genuinely, it was really hard to do. Oh, here's an interesting one. This is more than it. pure nutrition side than like energy side. But what the hell? I think I know the answer. Again, I'm going to get myself in trouble here speaking out of turn because I'm not a nutritionist or a dietitian. But the question is, do fats and or proteins really block carb uptake or for high intensity or moderate too? So my understanding is, and I've actually seen a couple of papers to this effect where, because people don't eat, macros. People eat food, right? Unless you're on like a Soylent Green-esque sort of thing where you're just getting fair. Yeah, you're just eating like straight table sugar, butter, and whey, even whey powder. Yeah, even that's got a little fats and carbs in it too. So what it seems like happens is, well, In the nutrition literature many years ago, it seemed like they had this kind of revolution of like, oh, people don't eat, we cannot just kind of inject people with glucose and see what happens and that's going to be like, you know, whatever. We can't just have people drink glucose water and be like, okay, cool, that's how these people handle carbs. Because when you start to mix in fats and proteins and fiber, it seems to slow down the absorption of carbohydrates. and so that's one of the reasons that like I used to be more into like the glycemic index kind of thing but that's my understanding is that's if you just eat that carbohydrate alone so if you're eating kind of like food and not just like this carb only then it's going to be a quite a different absorption rate so that's also one of the reasons why during exercise typically nobody's saying you know for like The way most people train for just a couple hours, most people are not saying you need fats and proteins during this two-hour ride. It's all about the carbohydrates because you don't want to slow down the absorption of those carbohydrates while you are doing intense exercise. So that's my understanding so far anyway. Yeah, I think the other thing is like it's like it maybe matters for very special cases. But it's the sort of thing that I think somehow people latch onto it in the popular diet zeitgeist. They're like, oh, this really matters, blah, blah, blah. And they're like, eh, maybe it probably doesn't. Like a lot of things. Yeah. Okay. If only it was that easy. If only things were just, oh, you just do this one simple trick. Doctors hate it. Okay, so that's all of our questions, and they were kind of mostly on topic, and I hope I didn't put my foot in my mouth too much speaking out of turn on nutrition stuff where I'm only kind of a dilettante, but I really tried to represent the best of my knowledge and the best of what's in the literature here so far. So if I got anything wrong, I do apologize and we will issue corrections in future podcasts, probably in the next one if I really fucked up because I've certainly done that before on the podcast and I get like eight DMs like, hey, what about this? Or you shouldn't have said this and I'm like, oops. And so, yeah, we will have a correction issued if, but I don't know, it seems like it's pretty straightforward to go back over. What we were talking about, you know, you don't only need to replace carbs on your rides. You need to think about your total energy balance is a way better way to think about it. Burning more fats on your rides does not necessarily mean losing weight. You know, spending energy on your rides and having a small sustainable deficit is the way to lose weight. And your BMR, as calculated by some calculator, plus your bike kilojoules, are not your energy needs. Because just that equation alone is missing the thermic effect of food and your non-activity exercise like thermogenesis. So that's an incomplete equation. At the very least is a good way to boil that down. So any other thoughts apart from that? No, I think that sounds pretty good. Cool. All right. Well, thank you, everybody, for listening in to this podcast. And we will have a lot more on all that kind of stuff in future Wattstock episodes as I continue to dig into the literature and pick a couple papers to really pull apart and dig into that I feel are representative of some of these topics. And hopefully we'll have some guests. I've reached out to quite a few people who do research on these topics to come on the podcast, and they've all said no. It's not that they don't want to come on the podcast. They're all very, very busy people. So that is why they have not been on the podcast. And I really wanted to kind of get into some of this sooner than later. So I feel like this is a topic where I feel like a lot of people don't understand the more holistic energy balance side of things. And a lot of people focus more on the fats and carbs thing. So I hope that this is going to help. rather than hinder. And also just understanding that the body's energy counting is pretty good itself, but our calculations, our estimations of the body's energy counting are usually pretty bad. And so we've got to, we can do some fuzzy math, but we've still got to use some... Things like, how do you feel? Can you focus? Are you sleeping well? Are you hungry? How's your performance? All that kind of stuff can go into, are you eating enough? And in my estimation, a lot of people are not only dehydrated, but also not eating enough. especially on the bike. So anyway, consult a real nutritionist or dietitian if you can. Again, reach out to me, empiricalcycling at gmail.com if you would like some recommendations. And if you would like to support the podcast, empiricalcycling.com slash donate. If you want to reach out for a consultation like we talked about earlier or for coaching, please email me again, empiricalcycling at gmail.com. And if you want to follow along on the Instagram at empiricalcycling up in the stories, you can ask your questions there for the future podcasts or the weekend AMAs. Thanks, everybody. Bye. See ya.