 So body fat for runners. Let's talk a little bit about how it affects performance, how low you can go and still be healthy, the difference between males and females, the difference, how it differs in importance depending on race distance and all of that. So let's jump right into it. So as runners, we obviously care about performance, at least some of us do, and that means we care about our weight, because essentially the lighter you are, the easier it is to move, the faster you're probably going to get to the finish line and a race, but only down to a point. And there's also sometimes where more weight might actually be beneficial. So here's the thing, our weight really consists of three, you know, well, there's several factors, but there are three factors that vary quite a lot, okay? And that is muscle, water and fat. Of course, there's also the weight of bone and certain other things, but those vary less and we can't do much to affect it. So water weight, we're not going to talk about that today, but that's essentially, you know, if you eat a lot of salt one day, you're going to hold on to some more water, that sort of thing. If you're fully stocked with glycogen, I'm going to hold on to some more water, but that's a good thing, right? You weigh more because you're having all that glycogen and there's water associated with the glycogen, but that glycogen is going to help you go fast, okay? So if you strip your body from glycogen, you're going to lose actually a few kilos of weight, but you're not going to be faster, you're going to be slower because you don't have the glycogen. So that's the water. Muscle, here's the thing, muscle matters, right? Because the muscle actually moves you to the finish line. So if you lose muscle, you might not become faster, even though you're losing weight, and if you look at someone who's sprinting, 100 meter sprinter, they're pretty, they're pretty strong, right? If you look at 100 meter sprinters, 200 meters, even 400 meters runners, actually the shorter the race distance, the more muscle you typically see on the runner, because they need that power. It's explosive. It's almost like weightlifting, where it has to do with strength to a large extent. As you move up in distance, we get into endurance, which is a sort of different thing, and that's when it's good to be lighter. So regardless of distance, we want to be as strong as possible for as little weight as possible. And for sprinters, that weight needs to be a bit higher because of the muscle, whereas in long distance, it can be lower. Now we get to the fat. So fat has a lot of different functions in the body, and it is important. And if you go too low, you die, like literally. If you actually go all the way down, you die, okay? You need essential body fat, it's what it's called. There's a certain amount of body fat that's essential for your health. You need that body fat in order to be healthy, and if you go lower, you will get very sick. Now, when we're talking about fat, we usually talk about it in terms of percentage of body weight. This is percent body fat, okay? So if you weigh 100 kilos, and you have 10 kilos of fat on you, then you're actually a very lean 100 kilo guy. That's 10% body fat, okay? So I don't know my body fat because you can test it in different ways, and I haven't tested it for a while. And I don't know, but I'm guessing my body fat is maybe around 12% or something like that, okay? So that means that 12% of my weight, I weigh 68 kilos, 12% of that, is 68 times 0.12. That's a little more than 8 kilos of fat on my body, 8 kilos. Okay, typically what they say is that for a male, because it's different from male to females, for a male, essential body fat, some people say as low as 3%, 3%, 4% is essential, others maybe go as high as 5 or 6, saying that's essential. But certainly anything over 6% body fat is non-essential fat, okay? Meaning you don't have to have it. But, you know, I haven't seen all the research and based on what I have seen, it seems that it might still be a good idea to not go as low as 5 or 6. Maybe you want to go to 8, 9 or 10, or even as me, I'm probably around 12, which is fine as well. Because in the other end of the spectrum, you have an upper limit. We'll get to the female number soon. In the other end of the spectrum, you have an upper number, which is sort of like, when you go above this, you're going to start seeing a decline in your health. Essentially, you start getting obese, right? And for males, that's probably, I don't know, maybe 18, 20% body fat. When you go above 20%, you're probably less healthy than you could be. So somewhere in the 5 to 15% range is probably optimal. Above that, you start and get into the high numbers and if you go below 5, you're definitely too low. And when you're too low, you actually lose your performance and you actually lose your health, which will affect your performance natively. Now for females, they carry a little bit more essential fat. So typically, I've heard that females need to stay above 10 to 12%. That's their essential body fat. And they can go as high as up to 20% and actually still be perfectly healthy, might even be able to go to 25 and actually be spot on in terms of body fat. And it's very important for women to have healthy body fat levels. It affects their fertility and just as with males, it affects their hormones. And what happens a lot, it's known as the female athlete triad. It's a problem that affects women when they're training too much, not getting enough calories and or going too low in terms of body fat. They lose their menstruation, the period, they might get osteoporosis, overtraining syndrome, certain different things happen, which is not good. So if you're losing a period, you're probably too low. And typically if you can see the six pack on a girl, if you really can see the six pack, she's probably below 12% body fat and that's probably not a good idea. So I would say based on what I've seen girls should probably stay between 13 to 20% of body fat, probably towards the upper end of that actually like 18 to 20 is probably better. Now, here's the thing. As a runner, you obviously want to be as light as possible as a long distance runner anyway, because you don't want to carry excess weight. That's just going to slow you down unnecessarily. And when we're talking about running performance, the one parameter that is very often talked about is VO2 max. And VO2 max essentially means the maximum, well, the V stands for volume, O stands for oxygen, and the two stands for oxygen as well, like O2 is oxygen. So VO2 max, the maximum amount of oxygen that your body can utilize. And it's usually measured in milliliters per kilo body weight per minute. So you'll see something like an elite athlete is having a VO2 max of 75 maybe, which means 75 milliliters of oxygen per kilo body weight per minute. Now, because it's a measure of how much oxygen you use per kilo, if you weigh less, that number will be higher. So if your VO2 max is say 50 and you go down a few kilos in weight, your VO2 max will go up, right? And it's a calculation you can do well pretty simply. If you weigh, if your VO2 max is 50 per kilo and you weigh 60 kilos, that's 3000 milliliters, 3 liters essentially of oxygen per minute. Now if you lose 5 kilos, now you weigh 55 kilos instead of 60. Now that's 3000 divided by 55 instead of 60. And now we actually, our VO2 max went from 50 milliliters per kilo up to 54 and a half per kilo. So we actually increased our VO2 max by almost 10% by losing 5 kilos. Now that's amazing, that's a lot. And if those 5 kilos of fat were completely unnecessary, excess fat, then it's probably a good idea to lose it. This performance increase would be something you should seek. Now, the problem is that when you're losing fat, you typically also lose a little bit of muscle. And your performance is typically not as good and your training adaptations are not as good in this period of time when you're losing weight because you're not in an optimally anabolic state. You're not in that billing phase. Your body is breaking down a little bit because you're losing weight, you're under eating. And this inhibits your performance gains and you also lose the muscle. So in the end, after that period of losing those 5 kilos over a couple of months or so, you might actually end up losing a little bit of performance because of it as well. At the end of the day, you might end up actually gaining because of the weight loss, but that's a balance that you always have to sort of find. And of course, what happens often is that athletes will get sort of hooked on this idea of losing weight. And they actually get into an eating disorder where anorexia, essentially, where they're just trying to lose weight, trying to lose weight in order to get faster. And this spirals down into a negative spiral where they're just killing their performance, killing their, you know, losing muscle and essentially ending up performing worse even though they lost their weight. So you've got to be careful with this idea of losing weight. But if you have excess fat to spare like a lot, it's probably a good idea to lose it in a healthy manner and then rebuild from there. How low can you go though, right? Because if you want to be at the top level, you want to be as light as possible, but still have all the muscle and all the performance that you need. And so I do think, you know, elite marathoners will probably get down to like 7%, maybe 6% some of them, 8% maybe. But what happens oftentimes is that they go down in the competition period and then they put on a couple of kilos in the off season just to get back to base level. I don't think it's healthy to go approaching that essential fat level. I think 12%, which is what I'm at, is probably much healthier overall. And I'm thinking in the future, when I'm getting into a very competitive shape, I might, you know, I might lose a couple of kilos just to sort of get that little bit of an edge. But then, you know, at the moment, I feel like it's not necessary for me to lose anything more. I'm pretty happy with my body fat levels now. And of course, you also got to, you know, do the calculations a little bit in terms of like, how much faster will you run a marathon, for example, by losing a kilo, right? And if you are, if you're at the elite level, if you're absolutely up at the top and you're trying to go from 204 to 203, well, yeah, then that one kilo or two, it might actually make a difference, a huge difference. It might be the difference between winning or not winning, okay? So in that situation, sure, it matters a lot. But if you're more of a mid-pack guy or a girl, if you're more looking at like a four-hour marathon maybe, or cracking three hours perhaps, like I'm going to try to do this year, and you can check out my video on my 2019 races, I'll put a link through there. Then losing a couple of kilos might not make that big of a difference. So a couple of minutes, a minute, I don't know. Is that really worth it? Maybe it is, maybe not. I'm thinking not. And the longer the distance in ultra-running, the more other variables play in, okay? So if you're down in the middle distances running 1500 meters, every second counts, every second counts. But in an ultra-marathon, sometimes the winner can be like an hour or two ahead of second place, okay? So things like hydration, nutrition, and guts, and pacing, and all these kind of things, they play a much bigger role in your success. And your body weight will matter less, okay? So, yeah, it's a big topic with a lot of emotion attached to it. People are very emotionally attached to their weight. I think it's healthy to have good body-fat levels. You don't want to go down approaching essential body-fat. Just, you know, get into the healthy range, and that's fine. And then once you get to a point where you really want to optimize your performance and every little bit counts, well, then you might choose to very carefully, very controlled, optimize your weight by losing a little bit of fat. And if you're a very fat, if you're a big fat person, then, of course, losing some weight might be a good idea for your performance and you might choose to do that first over a few months or even a year as you just lay down some basic fitness. And then later, when you're in your optimal weight, then you'll start focusing on that faster performance and higher performance gains. And, of course, if you're interested in my help losing weight or optimizing your performance, you can send me an email. If you really could do a coaching session, you can contact me actually through the LoneTrail Facebook page. So just send me a message there. There's a link in the description if you're interested in my advice. Now, I think that's it for now. Any questions you have, post them down in the comments. Thanks for watching. Please subscribe if you haven't done so already and I'll see you around. Bye.