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A little bit about where you are and what your lab studies.
Luc van Loon 6:34
Yeah, so what I have a chair in physiology of exercise and nutrition. My basically supervise a group of researchers but 30 people here at Maastricht University Medical Center, the study basically the interaction between physical activity and exercise and nutrition. And we do this in an attempt to improve performance, for example, in athletes, but all the way down to basically the impact of lack of physical activity and lack of sufficient nutrition in intensive care unit patients and everything in between. So anywhere where we can actually affect the interplay between nutrition and exercise.
Nick Jikomes 7:19
And normally when we talk about nutrition, you know, one of the big things people talk about are the major macronutrients, fats, carbohydrates, proteins, can you give people just a very basic overview of what those things are and how the body utilizes each type of macronutrient for energy.
Luc van Loon 7:40
Yeah, so it's interesting from my career basically started with the interaction between carbohydrate and fat metabolism. And my lab now mainly revolves around protein metabolism. So I have experienced some of the work in the different fields. So you have three basic macronutrients, carbohydrates, fats, and protein. The carbohydrates and the fats are basically substrates for energy provisions. So fuels basically, there's one big difference between the fuels, carbohydrates and fats, fat basically gives you a lot of energy per gram, almost twice as much as carbohydrates. And with fats, you can actually perform lower intensity exercise for a prolonged time duration. And that's a nice thing. And it also makes it very efficient fuel source, because you can actually store a lot of energy in the form of fat. That's why most of our energy stored in our body is stored as fat because if we would store it as carbohydrates, we will basically become twice as heavy. But the carbohydrates are an important fuel source, because you can actually sustain high intensity exercise with a carbohydrate oxidation. And that is because with high intensity exercise, it's easier to get the energy that is actually inside the carbohydrate to get them out faster. So in people that don't have a nutritional or biological background, I always explain it that fat is like diesel. And carbohydrates are like kerosene. So your body always uses a combination of the two, to mix and match in order to have the optimal performance. And that's also one of the reasons why you always hear about athletes taking carbohydrate drinks and stuff like that, because your total storage of carbohydrates is much smaller than fat. And that's why in some cases, carbohydrate supplementation helps people perform optimally during higher intensity exercise over a more prolonged period of time. Let's ensure it in a nutshell the basics of carbohydrates and fat and these indirect Of course, protein can be used as a substrate for energy provision, but it's it's not very efficient on that and the body doesn't really do it. Protein is basically a micronutrients that is composed of long strands of amino acids, the building blocks of proteins. And these amino acids are being used by the body to build proteins. And basically, you are composed of proteins. So your muscle, but also part of your bone and your organs. It's all made of proteins. And so we need protein in order to maintain our tissues, both health and integrity.
Nick Jikomes 10:26
And, you know, in terms of fats, their saturated and unsaturated fats, is there a difference between them in terms of, you know, how much ATP can be used, can be made, if you have one type versus the other, whether or not one is sort of better for giving you energy for exercise or anything like that.
Luc van Loon 10:46
Yeah, I mean, for for, for fats, it's all depends on of course, the size of the chain, you will have short chain fatty acids, you have long chain fatty acid, yes, prize. So let's roll so, so you have all kinds of fats. So that all differs between the different fats. And it's not necessarily a discussion about saturated or unsaturated fatty acids, that has much more to do with, of course, health benefits of that, and it's far beyond my level of expertise.
Nick Jikomes 11:18
Got it. And then in terms of, you know, Protein Protein is used, it can be used for energy, but it's primarily used, you know, to make to make the proteins of the body that do stuff. And I know that soy proteins are made out of amino acids. And I know that there's essential and non essential amino acids. And that can be important. When it comes to thinking about diet, can you just give people a basic overview of essential versus non essential amino acid, I think
Luc van Loon 11:46
that's I'm always confusing my students with this. So. So in general, proteins are now being used as a substrate exactly what you say. But of course, there are situations where you do look at people that are in the concentration camp, for example, or doing a hunger strike, or severe deprivation or anything, you actually see that the start burning the muscle, so you can actually just just use a substrate as a protein as a substrate, but on a normal fat conditions, basically, it only contributes very little to energy provision. Now, proteins exist in basically conglomerates of amino acids as the building blocks of proteins, and you have about 20 different amino acids and so much essential amino acids are named essential amino acids, and others are named non essential amino acids. The essential amino acids are being called this because the body can't synthesize these amino acids themselves. The non essential amino acids are amino acids that can be produced by the body, often through the conversion of essential amino acids. And so therefore, theoretically, they are non essential. However, in my perspective, I think the non essential amino, the non essential amino acids are still essentially your diets. Now, of course, that is always confusing to students, because then I'm actually telling you the non essential amino acids are essential. But it only refers to the capacity of the body to endogenously synthesized them.
Nick Jikomes 13:23
I see So, so essential amino acids, you absolutely have to get them from diet, because your body can't make them at all the non essential ones your body can make, but it's still important to very, very important to get them in the diet as well. And I'm sure we'll come to that. Now, in terms of carbohydrates, like I was, you know, they are sort of the the fast energy source, I guess we could say. And I was always taught as a kid, you know, playing sports and stuff that you know, my meal before, you know, the night before a game or something or my meal, before the game should be, you know, pasta or something that's got a lot of carbs, is that generally good advice, when you're doing exercise? Are carbs going to be the best thing to help fuel? The the high intensity exercise you're going to do? Doesn't matter if it's, you know, one type of exercise or the other and what's going on there.
Luc van Loon 14:17
Yeah, you said that this would be like a 90 minute discussion, but it could actually become a multi day discussion. But so what you need to understand is that you have about so on the total body that might be around. Yeah, let's let's say 100 and deliver another 350 Like maybe 500 grams of carbohydrates in the body. With that amount, you could sustain exercise on a high intensity level for about 60 minutes if you're if you're a good athlete. So any exercise that is of a moderate to a high intense The last thing more than 60 minutes might deplete your glycogen stores. And glycogen is stored in the liver and also in your muscle. And so in the muscle 350 to 700 grams in the liver, about 100 grams. So, in general about 500, or six on 700 grams, depending on how you what kind of diet you have, what your training status is, and the amount of muscle that you have, of course, but in about 60 minutes on a moderate to high intensity exercise, you can actually deplete your glycogen. And then the body is not able to maintain the high intensity for longer, and then you have to turn down your intensity, so slow down, or you might actually end up with basically hitting the wall as they say. So this depends, of course, the absolute intensity that you perform with because if somebody is very inactive and doesn't burn a lot of energy, then 60 minutes, he will take a lot more before he gets through his glycogen stores or her glycogen stores. For athletes, that could be 60 minutes. So if your exercise is more than 60 to 90 minutes of a monitor high intensity exercise, it's possible that you performance is limited by the availability of carbohydrates that are stored in your body. In that case, you can actually do two things to prevent the depletion of your glycogen stores by either storing up fueling up so ensure that your tanks are full with carbohydrates and or provide additional carbohydrates during the physical activity. Now what a lot of endurance athletes do several days before an important competition where the competition or the type of exercise might deplete your glycogen stores, they start fueling up with a lot of carbohydrates. So they use basically a high carbohydrate diet. And they actually increase the amount of carbohydrates in their diet on a daily basis, up to the level that almost from 50 to nearly 70% of the energy in the diet is provided by carbohydrates, carbohydrates, they titrate down their their training their training amount in the first few days before exercise, and that loads up your tank, so you have a maximum amount of glycogen in your muscle. Then in the morning, like two hours before the competition, they typically have a small, small meal more a small carbohydrate rich meal, which also loads up deliver the last part of the liver because overnight to deliver has been giving some off the glycogen glycogen into systemics is in the blood in order to maintain glucose levels. So you fill up the glycogen as well. And then you're all your things are basically full when you start the exercise. Now makes it possible that you don't need any carbohydrates during the exercise. But of course, if you have like seven hours of cycling or whatever, you are going to need additional carbohydrates being ingested during the exercise. And that's why people invented sports drinks and gels and all that stuff.
Nick Jikomes 18:11
I see. So if you're doing high intensity exercise for an extended period of time, where there's a risk of using up all of your glycogen stores, you definitely want to eat carbohydrates beforehand. So you're Yeah, so if you're doing the Tour de France, or you're just working out really, really hard. You want to eat a high carb meal the night before, and probably get some carbohydrates a couple hours or so before your exercise. And if you do that, you'll have enough fuel to maintain that high intensity. And if you don't have enough, well, then nothing catastrophic will happen. You just won't be able to perform at like peak level.
Luc van Loon 18:51
Correct. Or if you still try and you get depleted, you might actually get hypoglycemic, and then what people call you hit the wall, and you have to basically stop cycling because you're exhausted. But in general, it just means you have to titrate down your intensity, so you can't keep up with the pack anymore.
Nick Jikomes 19:09
I see I see. And is there a high intensity? Is that just defined by you know the amount of fuel you're burning period? Or does it additionally matter in some way whether you're doing like an endurance type of exercise versus weightlifting or something?
Luc van Loon 19:25
Very, very good. Very good question. So, so I'm basically talking about moderate to high intensity exercise because I mean, you can't keep up high intensity exercise for seven hours. So it completely depends on your definition of moderate to high but moderate to high intensity exercise. So basically competitive intensity. But also intermittent type exercise activities like playing soccer for example. Where you do repeated Sprint's basically or basketball or whatever. That is also a way to really go through your glycogen stores very rapidly. Even though it's not continuous exercise, because especially the high intensity exercise also uses a lot of carbohydrates. So even an 90 minute soccer game will actually cause a lot of depletion of your, your glycogen stores. So it's the same for those kinds of activities.
Nick Jikomes 20:18
And is there a difference between, like the different types of carbohydrates in terms of how quickly they can be used for energy or any, any other considerations? So you know, glucose versus fructose, you know, the carbs that you're gonna find in like a pasta or something like that?
Luc van Loon 20:34
Yeah, so. So basically, all carbohydrates are generally used as long as they are that digestible. But especially for during exercise, and also for post exercise repletion of your glycogen stores. They typically, they typically use high glycemic foods so rapidly digestible, easily available. And in those cases, if you if you look at for example, j also sports drinks for doing exercise. It's often composed of glucose maltose, which is basically 22 glucose molecules together, or longer, longer chains of glucose, glucose polymers, like multi dextran. Sometimes we're fructose, or sucrose. Sucrose is what we find in our sugar cubes, which is basically a disaccharide. So it's glucose and fructose coupled together that sucrose, it's the sugar that we know from the sugar cubes are the sugar that we put in our coffee. All of those sources are basically used in can be used and are rapidly digestible leparoux outlet rapidly available and rapidly oxidized. There seem to be limitations to the amount of carbohydrates that you can ingest during exercise that becomes available in the circulation and can be used for oxidation. And it's typically for glucose that's around 6060 to 70 grams per hour. So one to 1.1 grams of oxidation grams per minute that are being oxidized. So you don't need to ingest more than 60 to 70 grams. However, while ago, people also found that very, the top athletes can actually consume up to 90 grams per hour, and actually oxidize it, but only if they combine that with fructose. And now they have the popular term of multiple transportable carbohydrates, which basically says that the limitations in glucose is the uptake in the intestine. And fructose near follows a different pathway. So if you combine glucose and fructose, basically, the top athletes can go up to 90 grams per hour, most of our more mere mortals won't be they'll never get above to 60 grams per hour, probably. But that is the basically the limitation that you have. So it's not the limitless amount of carbohydrates that you can supply, even if you have the right carbohydrate source during exercise.
Nick Jikomes 23:01
I see. So for high intensity exercise, like a sports drink that has sugar in it like Gatorade or something that that actually is a good choice.
Luc van Loon 23:12
Depends on what your aim is, if your aim is to, to maintain moderate to high intensity exercise for prolonged periods, then sports drinks can prolong performance and reduce fatigue. Of course, the question is, what is your aim of your exercise? Is your exercise to perform maximally? Or is it to burn fat? Or to look better? Or is it for health perspective? So that is always the discussion, of course. I mean, you know how it goes, I might still be able to lose about 10 kilograms of excess fat that I have on my body. But I still buy by a racing bike that is under 10 kilograms. So a lot of people are still trying to optimize performance, even though we're not professional athletes. And we're not. We don't have to pay our mortgage from our sports performance. So it completely depends if you want to maximize before performance for some reason. And it's very special to you then then supposed to he's can improve your performance.
Nick Jikomes 24:18
I see. But if you're the average person who's probably not performing at an elite level, and your goal is to lose weight, that could end up being counterproductive.
Luc van Loon 24:29
Yeah, I mean, you've seen you I assume that you have gone to see a gym in sight. And you see people sitting on one of those benches where you can do app crunches and they sit there for about an hour. They drink one of those sports drinks and you can actually easily go out you don't need to calculate a taxi tell them that they actually ingested more calories than they burned on that on that bench.
Nick Jikomes 24:53
I see that makes that makes a lot of sense actually. Um, so switching gears a bit Little bit talking about things like protein physiology and protein supplementation and stuff like that. So if you're doing resistance training, and your goal is to build or maintain muscle mass, that's, that's the context. I want to think in here. One of the big areas that you just hear a lot about these days is plant versus animal based foods and diets, and plant versus animal based proteins. Can you start off by talking a little bit about are there like fundamental differences between animal and plant proteins in terms of their structure, and how the body actually like digests them?
Luc van Loon 25:39
Yeah, I would love going there. But I'm not think we need to take one step back. to first understand what proteins are, why we need them. And whether supplementation has a benefit, and then go towards the legacy of different proteins in the differences in quality, if you may. So our body is constantly breaking down proteins and building them up. Now also, later on, we can discuss other organs, but we'll stick to the muscle for now, your muscle has a turnover rates of one to 2% per day. That means that your muscle, your protein should, which is your muscle is constantly being broken down and build up again. That is amazing. Because that means that one to 2% per day, that means in 50 to 100 days, you have completely remodeled your muscle. So this is a misconception that a lot of people have because they think the muscle that they have that they always have that muscle now it's constantly being refurbished. So it's not like you lose your muscle, you build up your muscle. Now your muscle is constantly refurbished, like just like a house, the house is still there. But everything has been changed over the years. So you're constantly refurbishing your muscle and that is convenient. We call it muscle plasticity. I saw it you also invite a lot of neuroscientists who will talk about brain plasticity, or neuroplasticity, but you have also something like like muscle plasticity. Now, that is very convenient. So our muscle adapts to our use of the muscle because it's very inefficient to walk or walk around with muscles that you don't need. And you can easily see that if you picture yourself I always have these pictures for for presentations. And on the left, I always show a famous endurance athlete, by the turn cyclist or triathlete, and on the other side of bodybuilding, now picture the upper body of a professional endurance athletes, and that of a bodybuilder, huge phenotypic difference. I mean, the small guy versus the huge guy, their muscle has adapted to the type of exercise. And so that's convenient. If you started different, different, different and different sports and you start doing resistance training, you'll build up muscle, if you started going and running a marathon, you'll actually start looking more like a marathon runner. So your muscle adapts. The opposite is also true. It's also I mean that is a positive point, we call it muscle reconditioning. But you're also are at high risk of deconditioning. And that's when we lose the anabolic stimuli. To maintain muscle, we actually can lose muscle very rapidly when you stop eating, when you become immobilized. Remember, if you might have broken a leg or, or an arm and you've been in the cast, or you were in bed for a few days with the flu or with COVID, you see rapid muscle loss. And only when you see that, you realize that turnover rate of one to 2% per day is actually true. And so muscle needs to be stimulated to grow constantly in order to maintain the muscle that you have, both from a mass perspective, but also functionality and quality. And so this is something that we do every day because we get these stimuli every day. And that sounds very tiring. But the stimuli we have everyday it's physical activity and food intake. And so physical activity is one factor. The other factor is simply food intake. If you ingest protein in the form of a meal, you will actually stimulate muscle protein synthesis directly following digestion of your protein, the amino acids appear in a circulation, they actually at some point, reached the muscle, and they directly stimulate the muscle to stimulate muscle protein synthesis. It's really awesome to see this and this, of course has been known in research for a long time. We've done some work to actually show this and make it even more clear to people what is really happening and I'll come to that later. But simply eating stimulates muscle protein synthesis, so it's an important factor to maintaining muscle.
Nick Jikomes 29:47
And I suppose that's why when people are bulking up they they simply just eat more protein.
Luc van Loon 29:54
Yes, but it's doesn't necessarily mean that more protein is actually building more muscle bigger cuz if that will be sold, and I could basically sit here and go away protein supplements or eat tremendous amounts of eggs and meat, and that would be 300 kilograms of fat free mass by the end of the year doesn't work like that. So it's a it's a much more difficult, complex system where the interaction between physical activity and food intake are interplay, what is really interesting to see if you perform physical activity and you eat afterwards, your capacity to increase muscle protein synthesis is actually increased. So in other words, physical activity makes your muscle more sensitive to the anabolic response to food intake. So these two factors have synergy. And that's why there's a lot of discussion or there's a lot of interest in combining physical activity with protein intake, because they actually benefited.
Nick Jikomes 30:54
I see. So that would that would imply that the timing is also crucial here, that, you know, if if physical activity resistant training is priming your body to be more sensitive to its anabolic response to food ingestion, protein ingestion, then when you eat relative to when you work out would seem to be very important. Do we know much about sort of what the optimal timing is there?
Luc van Loon 31:17
Yeah, I mean, this is something that my lab was particularly interested in. So most of the studies, we basically perform exercise on that exercise and eat something in the morning and then respond and then see the response in the next few hours using stabilized traces and stuff like that. But how one meal affects the other meal and the other meal, etc, we don't know, we've worked around. So if every meal, we now believe that basically, every meal should have enough protein, to get a nice anabolic response. So that on a 24 or 48 hour level, you basically have investment, muscle maintenance. So that means every meal breakfast lunch, dinner should should provide enough protein. Now, we also have an issue with a lot of patients that, for example, lose a lot of muscle during a period where they can't eat a lot. And so we try to add another meal in the day, which is similar to what a lot of athletes do as well, because most athletes eat more than than three times a day. So to increase the number of anabolic points throughout today, and we started doing that prior to sleep. And the first study we did, it's pretty cool is we actually provided people with protein while they were sleeping. So we had a bunch of older people that were willing to participate in the studies. So what we would do is actually would take a muscle biopsy from the leg, then start a tracer infusion overnight, and provide them with intrinsically labeled protein and two o'clock while they were sleeping via nasal gastric tube. And then actually, we could by taking blood samples or retractable lines, so they wouldn't wake up. And then I would wake them up in the morning with a muscle biopsy. Basically, it's amazing that these guys actually sign up for it. It's really awesome to work with these people. And so what we could see in that study, and this is really a proof of principle study, because we wanted to know whether the guts or the gastrointestinal tract is capable of digesting protein, whether those protein derived amino acids are released into circulation, and whether they are incorporated into muscle and stimulating muscle protein since it's not at all worked. So even if you provide the protein in the guts at two o'clock at night while they're sleeping, you see that next it's nicely digested and absorbed, and stimulates muscle protein synthesis during sleep. So this is a strategy that you can use to prevent or attenuate muscle loss in patients at higher risk of losing muscle for a certain period of time. Now, strangely enough when we published that study for the first time, but because afterwards, we've done it again in other in other settings, as we got a lot of calls from coaches that were actually reading those that literature I was surprised by that asking asking me where they could get those nasal gastric tubes. Now, that was scary, because they didn't get that this was a proof of principle study, just showing that your gut function is at night and that you can have muscle protein synthesis, during sleep. But of course, the easy translation of this research is simply that you can have a protein rich neck before you go to bed. So between your evening dinner, and going to bed, and that is an issue in a lot of hospitals also here is that people get that evening dinner like five or six o'clock in the evening. And then they they don't ingest any protein for up to then breakfast the next morning. And that's a very long period to be without protein, especially when you're at high risk of losing muscle. So this is basically the proof of principle to suggest that approach To enrich snack in the evening can help you to preserve muscle mass during a period of, for example, in activity or reduced food intake or whatever. And of course, it's now also used and we've also done this with, with athletes, recreational athletes, being used by athletes to optimize recovery, for example, during heavy training periods. So, for example, most of us, if we exercise, we do this in the evening. And so if you already had your dinner, you're exercising later that evening, it's good to have a protein rich snack after the training session, in order to allow the the adaptive response to recovery, if you may, during overnight to optimize that and provide sufficient amino acids to support that adaptive response, and basically improve the efficiency of your training.
Nick Jikomes 35:55
And does this have anything to do with circadian rhythms and circadian effects of protein synthesis at a cellular level? So in other words, what part of the sleep wake wake cycle is most of the protein synthesis occurring? Is it occurring at all times to some extent is concentrated during sleep or during waking?
Luc van Loon 36:15
Yeah, the concepts that we basically have, I mean, there's not much stuff done on nightly protein synthesis is that we believe that all three meals are basically the three meals throughout the day, will stimulate muscle protein synthesis, reduced protein breakdown, so there's a net positive response. And then during the night, when you're basically depleted of protein, you have a negative protein balance, meaning your protein synthesis is not stimulated, and protein oxidation is a bit increased. And those two will keep them balanced. So you maintain your muscle mass and longer level. But however, as we've seen, when you provide some protein prior to sleep, you can actually change that, that overnight protein balanced by increasing and making a more positive protein balance.
Nick Jikomes 37:05
And so the the advice that I hear most often in terms of sleep and eating is that you should not have a big meal too close to when you go to bed. Is that generally good advice in terms of preserving sleep quality? But at the same time? Are you saying that if you're trying to build and maintain muscle mass, that you actually probably do want to have a high protein snack at least before bed?
Luc van Loon 37:33
Yeah, so I don't know what what what the what the basic the scientists on the potential negative effects of a large meal before going to bed? Because I'm not sure whether they're they're not saying that that or not, I wouldn't eat a huge meal before going to bed. But you notice yourself, if you go I'm not sure whether you still have relatives in Greece, but I don't think that you have to suggest that you have dinner at seven o'clock in the evening.
Nick Jikomes 38:03
Yeah, I think I think that's right,
Luc van Loon 38:05
exactly. So in a lot of the Mediterranean countries, I mean, food intake is the main meal is actually ingested relatively late at night. And in general, we actually say that the Mediterranean diet is actually healthy. So I'm not sure that there's any negative effect there. The only thing that I'm saying if you eat relatively early, then it you actually might consider a light protein rich snack, after your training session and evening, to optimize your adaptive response to the exercise, we have actually looked at how it affects your your protein intake, the next day, for example of breakfast, we didn't see an impact there. So people just because if people don't eat less breakfast, especially in the hospital, it's not overall it does doesn't necessarily help. But actually, they eat the same thing. So it doesn't necessarily affect either food intake the next day. And for all the sleep parameters that we actually did look at even though it's not our focus, of course, we didn't see any impairments in sleep quality.
Nick Jikomes 39:08
I see. So in summary, it would sound like if you are eating your last meal at a normal time for an American. So let's say 6pm 7pm, something like that. You're going to bed a few hours later, if you're trying to build and maintain muscle mass, probably a good idea to have a protein rich snack closer to when you go to bed because otherwise you will be going into negative protein balance throughout the night in those few hours.
Luc van Loon 39:35
Assuming you had a normal meal, I mean, if you actually have a ridiculous meal, if if a huge I mean huge amount of meat, for example, it might not have any benefits because you're still you're still digesting your food from six o'clock. But with normal meals, yes, sodas do things. It's not only focusing on that protein rich snack in the evening, but ensuring that every main meal has enough power. attend. And what we often see is that people hardly consume any protein at breakfast, and then relatively little at lunch, and then a huge amount. And then. So at this moment, most of my colleagues, and I believe that a good distribution of protein throughout today is the best the best option. And that could be like the three main meals, like at least 20 to 20 grams of high quality protein each meal. And then especially if you're at higher risk of losing muscle, or you're trying to build muscle, then a fourth meal, if you may, probably asleep.
Nick Jikomes 40:38
I see. And you said high quality protein there. And I want to talk about that. Because you know, when you look at the nutrition label on food, you know, it just sort of treats protein is Protein Protein is always 20 grams here. 20 grams, there are 10 grams here, 10 grams there, what is protein quality referred to and how does that start to become relevant here?
Luc van Loon 41:01
Yeah, that's, that's, that's, that's really a cool topic. So, first of all quality, I mean, this quality scores on proteins. And we always talk about quality, but what is quality and I always tell the students the following, if is a certain coat of high quality or not now, proper, probably that depends on how you're using. If you have a woolen coat, and you're standing somewhere in a cold, cold environment out of the wind, you think like, oh, this woolen coat is great. But then suddenly, when you're standing in the rain and the winds, I don't think you'll find your woolen coats to be very high quality, you probably preferred raincoats.
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