Is Lighter Always Faster? Weight Loss, RED-S, and Fueling Risks for Runners - Dr David Lipman

So David, is light always faster with runners? I don't think light is faster always for anybody, even cyclists, anyone like that. I think there is a lower bound at which we end up with problems. I think the view that the body is purely a machine that doesn't have emotions and hormones I think is narrow-sighted. I think you have to appreciate those things exist. But at the same time, there's no massive advantage to carrying excessive adipose tissue. So like there's significant fat, I don't think is a smart thing to be carried or is a helpful thing to be carrying from a health or performance standpoint. But there is an argument that carrying, let's call it more than a small amount of fat, not being super lean, is helpful in that you have a caloric surplus so that you don't have to be in a caloric balance every day or every week or every month. So if you've got a bit of a buffer there because whilst the thermodynamics says it's calories in, calories out, some degree, there's certainly a bit of a black box from an absorption and utilization and those sort of things when we talk about what we eat, right? So something isn't in your body when it goes in your mouth, it's in your body once it leaves your intestinal tract, right? So there is a straight lot or is a, here is a tube from your mouth, your anus, all of which is outside of your body technically, which people don't usually acknowledge. Yes, no, I'm keen to dive into this topic a little bit more in the next 10 to 15 minutes because I think some people have maybe developed an opinion that I have always believed that lighter is always faster and I'm not necessarily believed that. I've mostly looked at my own experiences in realizing when I've compared myself in photos of runners around my standard, that I'm a little bit bigger and chunkier than others and when I've lost the weight, it's become a situation where I've gotten faster. But we've both spoken about Ryan Hall, one of the best marathoners of all time, who got to a point where he was very lean and ran 204, they're mentally at Boston in a beer that was a bit of a tailwind and 59, sub 60 minutes for a half marathon, but then went too far with it. Basically performance went backwards. I think he also developed an injury and he admitted publicly that he went too far with it, so it's definitely a case where it's not always the situation of getting leaner and getting skinnier is faster. But yeah, I thought I'd invite you to jump on about talk about this because you know quite a lot about it and what do you think of some of the risks involved in really trying to get as lean as possible because I'd like to hear more about that myself as I try and get a bit leaner over the next six to 12 months and try to run as fast as I can over the marathon? Yeah, I think there's a couple of things. I think so performance decrement comes at some point. You've just mentioned Ryan Hall, so that's probably an end stage of it. If you probably maintain, we had Jose Rhetta on our podcast talking about an energy deficit and you actually maintains a capacity for a little while, which is I think where people get caught is they keep getting leaner and leaner or lighter and lighter and lighter and they see their benefits of that for a short period of time and it's a sort of self-fulfilling loop and they think that more is always better, whether it's mileage or you know, carbohydrates or caffeine or whatever it is, this concept and run as about it is like more is better and so they think or less is better in this case and they think like less weight is more helpful. So I think that's kind of where people get caught out is actually a period where you maintain perhaps even in some respects improved performance for a while, despite the fact that you've gone too far is kind of what I'm getting out there. So there's that, I mean, the big one everyone will point to is relative energy deficiency in sport and you know, that exists, but there's an argument from the scientific community that it may not be an energy deficit and isolation. So the counter-argument to that from some good scientist Satsuki, you can prove, I think it was on the paper as well, is that it's never just energy deficit. It's energy deficit plus other stresses and they can be psychological problems, they can be work stresses, they can be family stresses, they can be training stress as well. So I think, and then looking at some of Trent Stellingworth's work, he talks about some of the combined pathways of under-fueling, so like the red S type picture and overtraining, like an overtraining type of picture. And that's again, it's, there's sort of a spectrum of overtraining from what we consider normal overreaching. You know, so an example that your list is maybe familiar with is like a canover type of special day. Right? We had these two huge training sessions, but then you had a long time to recover from that. You kind of have this, what we'd call functional overreaching for a bit. And then you have prolonged sort of medium term overtraining. Let's call this like long weeks or weeks would be something we would call non-functional overreaching. And you can come back from that. And then you get to like overtraining, which is, you know, months of having to have time off and that sort of stuff, which most people wouldn't get to, hopefully. But the point here being the one argument is it's purely an edge of difference at standpoint, that's Margot Mountjoy. It's the BJSM standpoint. The counter argument from the other researchers is that stress doesn't exist in a vacuum, and it's never just energetic stress. It's never just under-fueling. It's under-fueling in the context of other factors as well that are playing a role. So maybe there are arguing semantics, but the point here is like you kind of have that red S picture as an end stage of under-fueling, which is just adding another stress to the body. And I think that's maybe the easiest way for people to think about this is like which levers of stress are you pulling for adaptation and/or, well, yeah, that you can adapt to. So you're pulling a very hard training block, you know, you're going to altitude and you're doing those sort of things. So that's another lever. Are you adding heat stress? Are you adding gym sessions now? Because it's an extra-stressor. Have you got a stressful period of life with travel or a spouse or are you missing sleep, right? But from a, as a bucket standpoint, right, and anything that drains your bucket is a stressor and anything that fills your bucket is to help with recovery. It's like how much is going in versus coming out? And do you want food to be part of that? Because it may be that that's the straw that breaks the horse's back for you, right? And that then if that is the big lever that you pull, the energetic one, then maybe you end up with things like stress fractures or something like that. But they can come from a training perspective as well. Yes. So do you find it a bit unfortunate when people do point to specific one thing when it comes to like a stress fracture when it usually isn't just one thing? It's usually a series of things as you're kind of adhering to. It's usually a combination of two or three things that happen at the same time and sometimes it's just a training load that pushes you over the edge. But when the topic of red-ess, you know quite a bit about this, I do not. And I feel like this is a good little conversation for me to learn a bit more. Do you think my strategy around actually trying to lose weight and I suggest this to people that are interested in doing that, that also have the weight to lose, which is the important part because many people are already extremely lean and they probably do not need to lose the weight? Do you think that the carbohydrates cycling that I advocate for, pretty aggressive carbohydrates cycling around workouts in really going big with, you know, carbohydrates in the 12 hours before and three hours after? Do you think that doing that properly is sort of eliminating completely the chances of developing something like red-ess or I don't understand it in disordered very well either admittedly but do you think that really focusing on making that part important and really focusing on maybe maybe it's important to actually think about consuming a certain amount of carbohydrates or calories in that time, even though I've said on a previous piece of content to not worry about it and just go big, I don't know, begin to hear what you think about that but people have warned me about red-ess and I admittedly say I don't really understand it so maybe it's a good time for us to learn a bit more about it but basically what I'm asking is do these carbohydrates cycling windows eliminate the chance completely or a little bit of developing such problems? So the answer's always complex, it's always shades of grey, so you never eliminate risk. There's never a zero risk of getting red-ess unless I just don't think that exists for pretty much any runner. If you're running enough, you're at risk of it because you can just under eat for whatever reason, people will have experienced this for no, without intent. Some people just don't have big appetites that are naturally fairly lean and, you know, they will maybe struggle with this, right? So those people exist, fast metabolism or they poor absorbers of calories, I don't know what it is, but the point is we all know that friend who can eat whatever they want and they never gain weight. That person is at risk of red-ess probably if they start training significantly, period full stop. Now, how aggressive you have to be depends. And again, if you're running, call it 200 miles a week, which is hurt off, there's no question it's hurt off, you're at risk because just the energy turnover is significant, right? There's those two things are certain and I'm sure you have some triathletes, if you're training, you know, that sort of amount, 25 hours a week, 20 hours a week plus like that, that is a lot. And you are at risk because all those hours you generally aren't eating that much, even if you're hitting 120 grams an hour of carbs, which they won't be for all those hours, you're still just burning a lot, right? So there's that, that's the first thing I'd say is there's always a risk that is increasing evidence that part of the energy deficiency or part of the risk with red-ess and under fueling looks to be related specifically to carbohydrate. What I'm saying there is that carbohydrate seems to play a specific role in this. Now, again, this is early research and if anyone wants the research, I can dig it up for them and send it to them. It is very new. But that's not to say that carbohydrate to the only thing that matters, I certainly think you need a good amount of, or an appropriate amount of fat that is important for health, hormonal health, etc. Many of the hormones are steroid hormones, so they require an amount of fat as well. So you do need to eat some fat, it's not that you would eat zero fat. You certainly need some fat, but other than that, you certainly need to hit appropriate amount of protein, particularly if you're in a caloric deficit, to not lose muscle mass. And then you need to be hitting carbohydrate to fuel the higher intensity work you're doing, probably the bigger volume days as well. Because one of those misnomers is that you burn no carbs if you're running, say, zone two or below. That isn't true. You don't burn many carbs, but if your energy output is enough, even 5% of a lot of energy is a lot of carbs, right? So it's worthwhile remembering that as well. So all of that is to say you certainly need, I certainly think you can afford to cycle carbohydrates, and that would be what people call carbohydrate periodization. And it's well established, send in piece of research as big on this. this, he's built, you know, he's a co-founder of an app called Hexas, there's a nutrition tracking app that fundamentally is based off of this. World tour prototyping teams are using it, runners are using it, triathlete are using it. So, you know, that exists. It's called Hexas, I believe. So certainly cycling carbohydrates makes sense. You should go higher. The question is how low do you go on other days? And is that, you know, appropriate amounts? And I don't think you're going zero carbon on those days, but, yeah, that's, I guess that's hopefully that gives enough answer to it. Do you want to track calories? People certainly can do it. And you sort of mentioned eating disorders and like that spectrum, you know, I'm not a dietician. I've spent zero days being a dietician, but I've spoken to a lot of them, I've spoken to a lot of people in nutrition space researchers and otherwise around this and the risk factors. And basically, you kind of have a spectrum from, let's call it normal if we want to call it that or healthy, let's call it down to what people would call disordered eating and then eating disorder, per se. You know, some of what you're doing could be considered disordered eating and a lot of it depends upon how you're related to that and how it relates to it. I don't think knowing you and hearing you talk about it, I don't think you're on that spectrum. Or I don't think it's a disordered eating standpoint, but there are certainly people who, you know, things would be like how worried of you about going out to eat. Will you avoid going out with friends or sort of things? These are standard like screening questions that are like point towards disordered eating and eating disorders, right? And like, I'll put my hand up during medical school, I was very particular with my diet. And I probably was on a disordered eating spectrum. I don't think I truly ever worried. I don't think I was ever had an eating disorder, but I do think I was probably beyond a normal limit with how meticulous I was. I prepared all my meals, did all that sort of stuff, very like bodybuilding-esque and what I was doing bodybuilding, but I was actually running. But the point being I was doing that, I was also on a low carb diet and ended up funnily enough with the stress reduction in my tibia. So you know, these things happen to people and you can get down that way. So yeah, we all exist on different spectrum and you know, some people may consider yours towards the extreme end. I would say it's probably extreme end of normal rather than, let's call it less extreme end of pathological. Well, ask a question for you. Do you think it's a big problem to lose muscle mass as you're training for a marathon or a half marathon or a 10K or a 10K? I would say depends on where, so and depends on your goals, right? So there's no real advantage for you having big upper body muscles aside from health and your life, right? So I have always, you know, I've always looked at start lines. I've always been a heavier runner, period full stop, like I might be am I as 26 I believe. So I always joke that if you normalize a BMI, I might be competitive with Kipchogi. So, you know, like I've, I race in the sort of 83 kilogram range and I'm, you know, 5-10. So I'm very heavy for a runner. It's like a hundred, I don't know what that is, 170, 170, something counts. Point being, I'm quite heavy and I've always, and I've maintained a level of bulk before a health reason from a muscle mass perspective. I've always kept upper body weights in, you know, as one of those reasons, right? Because I, you know, I didn't want to sacrifice health in that respect. But you may say, you know, like, Fikipchogi is a good example, like here's another body mass that he needed for top end performance is not much period full stop. I don't think it's helpful in that respect. And, you know, top end elite performance isn't healthy. Even if we ignore the muscle mass side of things, just like the psychological aspects of it and all those things are not healthy, he used to go into training camp and leave his family behind for, you know, weeks at a time like that's, that's not what most people can say to healthy. So, I think with context of, you know, I haven't used that based off of exactly this, which is like what is health, what is performance and where they align and where they're not aligned. So yeah, like you don't need upper body muscle mass to run well unless you're a trauma runner using poles, but at the same time, you do need to consider like, most people who exist not purely for performance, they exist on a spectrum. And I tend to say to people like, you need to understand your line, are you 50, 50, are you 60, 40, are you 70, 30? How do you make those decisions? Because, you know, there's another argument that, you know, drinking up or eating or whatever it is you do, a bunch of carbohydrates per hour while you're running isn't necessarily the healthiest thing, even just for your dental health, right, just for your tea. And so, you know, there's a compromise you're making there on your health at some point as well. So you need to just understand where that is and make an important decision as an adult human. Yeah. Thanks a lot for the chat. I appreciate it. Thank you.