 Your body will, at any given time, choose a combination of mostly fat or carbohydrate to fuel your system. And as the intensity goes up, you burn more carbohydrate. And as a marathon runner, especially ultra marathon runner, your ability to burn fat at higher intensities for longer is good. Alright, so today I'm going to dive head first right into one of the biggest topics in training physiology and just running topics. And that is eating breakfast or not eating breakfast before going for a run in the morning, or more specifically really fat adaptations or carbohydrate intake and how it affects your training effect and training response rather. So it's a big topic and I'm going to be perfectly honest, I don't understand it completely yet. I know a lot about it, but I think even science as a whole doesn't even yet have all the answers when it comes to optimizing training effects and whether or not eating gives beneficial training adaptations or not. So I think this is more of a sort of discussion. I'm just sharing some of my thoughts regarding it, explaining some concepts and then we'll take it from there. So first of all, do you need to eat breakfast? Let's just answer it really simply first. Do you need to eat breakfast before you go for a run? The answer is no, you don't need to eat breakfast before you go for a run, but whether or not you should eat breakfast or not, that's another story. Obviously when we're going for a run, unless we're just not really caring about performance and we just want to get out and just move a little bit before we eat, that's fine. But if we're looking for performance improvements, if we're looking for the training effect, if we want to get better, then obviously we care about how carbohydrate intake specifically affects our performance. Fat intake, let's say for breakfast, like eating fatty breakfast, that would be pointless because you wouldn't actually realize those calories until much later because it takes so much time to digest, so it would be pointless. So we're really just dealing with carbohydrate intake. Carbs is what is quickly turned into fuel in your body and used. So we're really talking about carbohydrate intake versus no carbohydrate intake in the morning. You've got to realize that when people say skipping breakfast or going for a long run without taking any fuel, typically they're promoting it because it supposedly enhances your ability to burn fat. And that doesn't mean burning your fat and losing weight. Well, essentially it does mean burning your fat, but it doesn't necessarily mean losing weight. It means your body will at any given time choose a combination of mostly fat or carbohydrate to fuel your system. And as the intensity goes up, you burn more carbohydrate. And as a marathon runner, especially an ultra marathon runner, your ability to burn fat at higher intensities for longer is good because it means you're sparing your glycogen stores. Glycogen is your carbohydrate stored in your body. We store most of our carbohydrate glycogen in our muscles and some of it in our liver. Now, here's the thing. To train your fat metabolism, the best way to do it is to just run. When you're running for a long period of time, like these long runs, one, two hours, three more hours, you're really training your fat metabolism even if you are taking in carbohydrate, even if you're running with full carbohydrate stores. Now, if you restrict in carbohydrate, you will enhance your ability to burn fat, but science shows that you will also decrease your ability to burn carbohydrate. So it might give you that sort of slow gear that you can almost go forever at a really slow pace. If you're a fat adapted keto diet type person, but you're going to lose out on the ability to use that higher gear and run faster and run harder or quickly change pace, etc. And studies have shown that although fat metabolism is improved by carbohydrate restriction, it doesn't also necessarily or so far it hasn't translated into a performance improvement. And if we're looking for performance improvement, let's face it, that's really what we're doing, then restricting carbohydrate might not really be that useful, especially in terms of dietary restriction. Now, there's another way to restrict carbohydrate, and this is really what it's mostly about when we're talking about skipping breakfast. And that is essentially running on low carbohydrate stores. So as I said, we store glycogen in our muscles and our liver. And typically maybe 400-500 grams in our muscles and about 120 grams or so in our liver. The liver supplies bloodstream with sugar. So it maintains our blood sugar, which is important for our brain and our whole body, all the cells in the body. Whereas that muscle glycogen stays in the muscle and is only used when the muscle is used. So when you're sleeping at night, your liver is steadily dripping out glucose into the bloodstream. So you're depleting those liver glycogen stores, but your muscle glycogen stores remain the same. So when you wake up in the morning with essentially low liver glycogen, depending on how long you slept and how long since your last meal, right, when did you eat dinner tonight before, how much did you eat? Was it a high carbohydrate dinner that really stocked those glycogen stores or was it a fairly low carbohydrate meal which didn't really stock your glycogen stores well? Well, these are things to consider. But essentially at the morning you have some level of glycogen depletion in your liver, which means that after a certain amount of time running, let's say you wake up, you head out the door, starting out you've got some glycogen in your liver but not much and you essentially got full glycogen stores in your muscles. So your muscles will run on glycogen, but at a certain point, depending on those things I just mentioned, how much glycogen you have left in your liver based on your meal before the day, before how long you slept, etc., you will run out of liver glycogen and what happens then is that you get low blood sugar. Okay, and that's that feeling of just feeling unmotivated, losing your drive and just like you're out for running and just like it's bonking essentially, one type of bonking and you're just feeling completely empty and without any oomph. That's low blood sugar and that can be corrected like that by taking in sugar, okay? So that's just running out of liver glycogen. Your muscles have plenty of glycogen and can run for a few hours actually, technically speaking. So here's the thing, when we're talking about fat metabolism, when we're talking about optimizing our ability to burn fat as an athlete, we're really dealing with our muscle, our skeletal muscles ability to burn fat. So if we are to stress the muscle to get better at burning fat, then we have to deplete the muscle from glycogen before we start, not the liver. The fact that the liver is depleted when we start doesn't really do much for our overall adapting to fat metabolizing state. It actually just gives us low blood sugar and makes us feel miserable. It just doesn't do much. So when you wake up in the morning and go for a run without breakfast, it's not really that powerful in terms of optimizing your fat adaption. If you want to do that, you have to deplete all your glycogen stores, including your muscles, maybe the day before and then go on a really empty, like a bonking run, as they say, where you're just essentially running depleted. This, of course, should not be done too often. Whether or not it's beneficial to do it, it's still debated, who knows. But even if you do try it, it should only do maybe once a week or even less often, I would say, because it's really taxing on your body, it's difficult to recover from, hard on your immune system, that sort of thing. So anyway, back to the sort of original question, the simplicity of it anyway. Should you eat breakfast before you go for a run? Well, practically speaking, I would say, if you're just heading out for half-hour run, you don't really need to eat breakfast. You probably have enough liver glycogen to get you through that half-hour, no big deal. If you're going for an hour, though, or especially if you're going for a long run, for sure, you are going to run out of liver glycogen fairly soon, maybe after half an hour to an hour. And when that happens, your performance is going to really suck and you're just going to feel miserable and it's not going to give you that much benefit either. So in that situation, if you're going out for more than half an hour, I would suggest have a banana, have a couple of bananas, have a small breakfast essentially, or bring with you sugar, bring with you fuel, bring with you some dates, bring with you a gel or two, depending on how long you're going. Essentially, start consuming sugar before or during your run because there's no benefit in running out of liver glycogen so you're better off just restocking it and going out with some quality running. Now, of course, there are also the question of whether or not taking in sugar before or during will affect your ability to burn fat right there. And then that is true, you know, when you're taking in sugar, you get insulin, an insulin response, and that insulin response essentially then favors sugar metabolism over fat metabolism. But actually, insulin is quite blunted. The insulin response is very blunted when you're taking it in during exercise. So in that case, I would maybe, let's suppose you're going for a long run, I would perhaps start out without any breakfast. And then, like if you really want to emphasize the fat metabolism that is, going for a long run, if you're just going for an hour, have a banana, go for your hour, no problem. But if you're going for like a couple of hours, you want it to be a long run to stress that fat metabolism, I'll probably start out without breakfast. And then after like half an hour, start consuming, or even after 15 minutes even, start consuming a gel or a sugar mix and do that at regular intervals. And that insulin spike will actually be quite blunted and it's not going to affect your fat metabolism too much, I think. This is where I haven't fully understood as to the picture yet, so I'm not going to pretend like I know it all. I'm still understanding this whole concept. I'm a big fan of Dr. Asker-Jukendrip. He's a really cool guy. He knows a lot about... He's probably the most leading scientist when it comes to this field of carbohydrate and exercise science. So that's very interesting. Anyway, that's it. I think that's my thoughts regarding the subject. I typically do not eat breakfast if I'm heading out for just a short morning run. And most of the time my morning runs are always short because I hate running in the morning. And so sometimes if I feel like I need it, if I'm waking up and like I'm super hungry or like just low blood sugar, like totally run out of liver glycogen over the night, then I have a banana, you know, and then I head out. And it just feels so much better. Also bear in mind that if you're hungry, if you're low blood sugar and you're sort of running out and you're doing exercise for a little period there your body can mobilize the fat and start burning fat. Your body will actually burn a fairly high percentage of protein, which is essentially an muscle. So you're actually burning your muscle and that's no good. So instead of burning your muscle, just get that sugar in the morning if you feel like you need it when you go out for a run. And if you don't feel like you need it, you probably don't. And then you can go out no problem if it's a short run. All right, that's the question for today. Thanks for watching. Please do subscribe if you haven't done so already and check out some of my other videos on similar subjects. If you have any questions, you can send me a message over on the Loan Trail Facebook page. I'll be sure to answer it there. Have a great day. Bye.