MEDI214 Lecture 12 Transcript PDF

SPEAKER 0 Ok. Ok. Uh Good afternoon everyone. Is that volume? I know uh the volume's probably ok. Cos you can hear me anyway, but is that, can you hear it like echoing? Great. Um Good afternoon. I thought I'd start off today before we get into the content of just going through the quiz. Uh just to...

SPEAKER 0 Ok. Ok. Uh Good afternoon everyone. Is that volume? I know uh the volume's probably ok. Cos you can hear me anyway, but is that, can you hear it like echoing? Great. Um Good afternoon. I thought I'd start off today before we get into the content of just going through the quiz. Uh just to clarify something. We've had a few emails and it probably wasn't exactly clear uh after the, the first lecture. So we got the quiz, I think where the confusion probably lies is uh in the unit outline. It says it's due on Friday. So week three, Friday, I've changed that. So it's on Monday of week four, Monday, week four. The other thing is, um I I've had an email asking if it's open for 24 hours. It's, it's definitely not open for 24 hours. There's a 40 minute period that you can do it in. Um and, and you're 35 minutes to do it. That that means if you're having a bit of a computer glitch, you can't log in in the first minute or two. That's alright. No stress you'll get there. Um But basically when it opens it opens and closes at 1235. If you do it start at 1237 that's ok. But it opens at 12:35 p.m. on the Monday. Pretty much this time next week. Um, 35 minutes to complete 30 multiple choice questions. Um Can you do it at home? Yes. Can you do it in the library? Yes. Can you come in here and do it your lecture time? Yes. Um, you do it by yourselves, of course. Um And the reason why I know that some units have a, they do allow 24 hours or 48 hour period to do a quiz in. But just lately we found too, too much, um too many students would probably um doing the wrong thing there and it just creates headaches for everyone. So if it's open and closing this time, everyone does it at the same time, there's hopefully no collaboration and everyone does the right thing. Any questions before we move on from the quiz? Cool. Ok. So onto carbohydrates today. Um And before we, we start, I just want to highlight, I might have said it in the first lecture, but a lot of what we do in, in the lectures and uh uh uh especially from my perspective as sort of a diet, sports dietitian is from that angle, I suppose. Um But here within, within this unit, we're not gonna all come out as uh sports dieticians. Some, some may, some may just find interest in this. But hopefully we're gonna uh get an appreciation of some of the theories and research underpinning what happens there because it's gonna be out of our scope of practice most for most of us, once we, once we finish to give, you know, individual specific advice, that's the role of a dietitian or sports dietitian. But hopefully in this course, in through through this lecture, I will get an appreciation of the research, why the rec general recommendations of why they are, I suppose is, is the main thing here's electric outcomes. And for anyone who's done many 150 which is probably a lot, there might be some revision here for the first, um maybe third of third of this, but it is important because it puts in context the sports or exercise component. Um it relates to the energy systems. And if we, if we understand how carbohydrates are digested, that's going to influence the types of foods we're having and the reasons why we're having them, why sports shells are formulated the way they are, why sports drinks the way they are. So if that's, you just bear with us, we'll get through it. I think it's nice to do some revision anyway, cos it's probably a couple of years since you've done that. And then the second half of the lecture is more about the carbohydrate recommendations for various athletes and, and putting it into practice. So before we start off see, here we go. Here. Carbohydrates are found in the body predominantly in the form of and the storage form of in the muscle and liver tissue. What do we think? Sports glucose and glycogen? Very good. Yep. In humans. So, glucose and glycogen. So we found it in glucose if it's in the bloodstream and then if we want to store carbohydrates, the glycogen predominantly in the muscle and liver tissue and to extend that a little bit further. I suppose if we wanna, if that's the end outcome for, for humans, we wanna consume them, we find them in foods. Of course, we have three sort of categories, monosaccharide. So mono meaning one, saccharide, meaning sugar diet, meaning two. So two types of sugars and poly and many. And I suppose this is important if we put it in the sports or exercise um content because the body uses monosaccharide in, in glucose. We just said that um but we find them in polysaccharides in the food we eat. So we need to be able to break those down. Um the best we can. And I suppose as we train and we consume different types of carbohydrates. We're able to do that at, at a diff different rates. They're going to die, saccharide mini two and then into monosaccharide where we can actually use them. So here are our monosaccharide. This is ultimately when we consume foods, they, like we said, polysaccharides, we break them down. Um and essentially they will end up, um, in, in one of these monosaccharide, then it's up to our body to decide what to do with them at a later stage. Well, we've got glucose here and we can see on the glycemic index, it's 100 because that's what the, the G I, the glycemic index, how much it raises our blood sugar. Um, it, it's the, the metric or the standard that we use, How much does glucose um pure glucose influence it. So we can say that it's 100 we just said that it's found in circulating around the blood um and restored as glycogen. So that's in humans. Um And I suppose this last point which maybe new to, to some of us is that when we do add it to food, it, we call it dextrose. When we add glucose food, it's called dextrose. And you probably see that in if you pick up a sports gel or, or drink or something, sometimes you see dextros. So that might be somewhat a, a new concept there. Uh Then we have fructose, another monosaccharide. This one's found predominantly, I think it makes sense. Fruit and I think of fruit. So fructose. Um but we can see it's a little bit sweeter than a lot sweeter. Actually, in glucose, it doesn't raise the, the G I um Well, it doesn't raise our blood sugar as much as glucose. Um which is an interesting point. Um And probably good to know from a sports or exercise perspective because there might be times we wanna ride that rise of that blood sugar really quickly. So we can utilize that glucose. The glu well, it will become glucose eventually, but we want our blood sugar to be higher. Um And so perhaps fructose may not be the best choice. There might be other times when it maybe. So this, this matters in the, in, in the uh sports context. This actually matters. The G I index uh galactose uh is part of the lactose. It's not really common. Um Not too common in, in the um diet really. It's only found in, in milk. So we'll look at disaccharide in a minute. So we can see here the chemical structure of our monosaccharide. You don't need to know too much about this. But we, we know that um their chemical composition is the same six carbons, um 12 hydrogen and six oxygens. Um And how these are bonded went in our polysaccharides, the chains um changes and we'll get to that in a secondary look at starches. But before we get onto starches of polysaccharides, we look at our di sac rides. So easy way to remember these. If you ever got a question or it's just nice to know, I think is that each one, if you're thinking dice or two sugars, all of them, you'll notice have a glucose to start with. So that's one easy thing to remember if it's disaccharide, it's gonna have a glucose, easy to remember. And then it's just a different combination essentially of the um monosaccharide which give it the name. So we've got Zuko's here. The first one which is glucose plus fructose and sucrose to me. Sounds like sugar. And that's what it is when we think of white table sugar, brown table sugar. Um That's what it is at sucrose essentially. Uh If we think of sugar, do you want to know the difference between brown sugar and white sugar? I'll tell you that they're both pretty much all secret. What's the difference? Yeah, so it's more refined and do you know how or why or what it's with? Uh they could do but there's something in sort of cane, usually it's from cane um called molasses. And so the brown sugar you could argue is more, is a healthier choice cos it's slightly more nutrient dense, be more iron for other electrolytes but not, not much. It's, it's mostly sucrose, that's the difference. So when we think of table sugar, brown or white essentially, so uh to a large extent, um so it's glucose and fructose incidentally while we're here, we will look at um supplements and gels and things down the track. But if you pick up any gel these days or modern gel, the ratio in there is generally going to have glucose and fructose in there. And so this is why we're gonna get to in our lab uh in lab, when is that for six and seven, we're gonna test and I don't know the answer to this and I don't think the research is up to it, but we're gonna test ourselves in the lab, sugar water, which is glucose and fructose versus a bu gel, which is glucose and fructose. So, we're gonna test which one's good by testing our blood sugar and testing the malabsorption. We can test that. Looking at hydrogen gas expired, I've got, I just bought a new device to measure that. Um So that's a bit of an aside. But um that's see in the sports context. Yes, but we've learned this chemical structure. We learnt, we know what sucrose is. Um but it has some application now for sport and also how these are absorbed in our body to get uh to rise. Our blood sugar is gonna be a bit different now in the sports context. So we've got lactose and here we said, we always said it's one glucose molecule for all of our diakos. Um And here we have this uh vic lactose here. Um some milk sugar and MTO maltose, not that common in um human diets really. So here we are probably no surprises here that we've just got monosaccharide down together. There's usually a reducing end, it's shown here and these are disaccharide. So two sugars, but then we get onto our polysaccharides. So they can join together at these reducing uh ends. And uh they, they can also, so depending on this structure dictates the type of polysaccharides. They are. And we'll look at those. Probably. Now, here we are. So probably we heard a lot about starch. Starch is the plant equivalent. We said that in the human body, Glycogen um is how we store carbohydrates. That's very true. And in plants they do the same thing. But if they don't store Glycogen, they store starches and there's two predominant ones. So we've got Emelin and em Melos. So just you can think of that if it, if the human equivalent, statues of human equivalent, um they, they differ structurally, which is on the next slide. As you'll see, we've already spoken a little bit about Glycogen. That's the carbohydrates um that we can store very important as we'll see throughout this lecture um for particularly for endurance um athletes, but also team sports as well and, and other types. So that's our, that's our storage. Um And then fiber is um they're polysaccharides. So sugars joined together. But humans and cellulose is a good example. So it's more of the structural component within plants. Um usually cell walls of plants and we're not able really to break these down to a large extent, a little bit, but not much ha hardly at all. So it goes through a AG I tract and generally we do not digest them very well and we do not absorb the sugars from fiber, very healthy. And in my opinion, if you wanted to tell someone how to be the healthiest in a simple sentence. So just hit a or increase your fiber essentially because that takes care of all the nutrients. Generally speaking, the higher the fiber, generally the healthier the diet. Here's a look at some of the, the polysaccharide. So here's our glycogen and then he is our two predominant plant. Um starches, amlo, pectin and alos. And so these are all, all of these are glucose units just but it, they differ how they're bound together, which is important. Um Because here, we can see for glycogen if, if we i if humans store glycogen as a, a single chain like um amyloids is here. We could only chop those glucose units off at each end. And so Glycogen's great because uh we have enzymes to break these glucose units off and then to uu to utilize those for, for movement. So we can break, for example, we could break this little glucose over here, this one here. So we can sort of attack our glycogen, probably not the right word, but essentially cleave those um mono sacro as glucose in many areas at the same time to get a good release quickly. If it was starch, we could only chop here and here. So it's a lot slower. So there's no great way to classify carbohydrates. You probably would have seen some of these before sugars and starches. So sugars in the, you know, the the simple sugars or monosaccharide versus the starches. We just saw there for the plant storage. Um components, simple and complex kind of a as similar concept there, I suppose. But complex being more branched, longer chains, simple being the the single units minimally minimally processed. So perhaps, you know, more than the whole foods sugars and the the plant is in its entirety versus highly processed. We, we spoke about table sugar. Um All good is bad. Um Perhaps these are good to, to classify them, perhaps they're not. Um I'm I'm not, I'm not sure, but what I would say in the good and bad type at the end, there is, this is a iii I love showing this diagram if you've ever had taken on my car. So I've pretty much find a way to put this up cos we're looking now at whole grains. So we just spoke about plants having starches, we need those starches to f for, to use as carbohydrate to move around. And in the concept of having bad or good, this is I suppose where it originates from the, the whole grain and refined grain. And we can think about grains and many different types of grains, millet, oats, corn or grains, rice. Um And so essentially, if we think of the whole grain, we could think of a, let's use rice, it's brown and it's in its whole form versus the white version here. And so in the good and bad, this would be termed good, this whole grain here because it's in its whole form. And why it's important is because in its whole form, it's got bran and the, the germ here. But we can see when we refine a grain. So we go from the brown rice to the white form. Essentially, we're just left with the endosperm and this is starchy carbohydrates could be great for athletes for sure. Get those carbohydrates. Is it the healthiest choice? No, it's not the healthiest choice. And so this is where I sort of uh I'm somewhat mm not torn about sports nutrition, if not done well because there's a large focus on this refined grain because as athletes, we very often want to have the energy hit really quickly. We don't want too much fiber, we don't want G I issues. And so we're often told to have refined grains, which is great in many instances and we get into that. But if we're not careful when whole grains are endorsed as a huge component of everyday Australians and athletes diets, if we're not careful, we're losing this brand part, which is where most of the fiber kept along with lots of vitamins, minerals and other phytochemicals. And then the germ component too packed with B vitamins, vitamin E, phytochemicals, healthy fats, etcetera. So if we're taking those away, we're always having these refined grains with athletes, then it's probably not the healthiest choice. And so essentially that's where the, the good or bad or the, the, you know, the refined parts we think about cane sugar. Um you know, if you ate the whole plant that might be good, if we refine it to the sugar, we're, we're missing out potentially on nutrients. So keep this in mind in the context, I suppose of this whole unit but particularly carbohydrates as we continue. Ok. So on that note, the consumption of high sugar, low fiber foods and beverages maybe necessary at times for an athlete, the immediate energy needs um of exercise will outweigh the longer-term healthy diet perspective. So what are situations where this could be the case? What do we think? Put cards on the go? Mhm. Powering application. Whether they need just some sort of work to like replenish muscles like in stores and synthesize a just to get through that quick hit of energy in like a short period of time in comp Yeah, for sure. So competition for sure, it will be. Yeah. So perhaps it's a, I've never done it. I don't know, I'm not too familiar with powerlifting competitions, but there might be several lifts throughout the day. You need to keep your um blood sugar up the whole day. So if you have an uh if we had one of those whole grains, we just saw, it takes perhaps a couple of them. Well, depends, let's say 30 minutes an hour two hours to actually start to absorb some of those because it's packed with that fiber healthy option. But there's definitely, that's a good, a good for sure. Tournaments touch footy tournaments, footy netball tournaments for sure. We might need that quick hit for sure. So, on that note, then what high sugar, low fiber foods and beverages would you recommend? And why? So we're gonna get into this. But before we do, sorry. Lollies. Yes. Yeah. Yeah. Yeah. Sugar water. I like it. Yeah. Oh, no, no. Yeah. Yeah. So, yeah, so, so that's, and that, you know, we, we know that they're not healthy, right? Lollies, sugar water. Um Gatorades, they contain carbohydrates. It's gonna give us that spike in um blood sugar. Yeah, they're not healthy. So a lot of my research is sort of on this note just more recently in the last year or two is, is looking at athletes diet quality overall and refining particularly in endurance athletes. It's pretty poor, it's really poor. And so I did, I did a cross sectional survey of the athletes in Ultra Trail Australia. Uh 100 K race in the Blue Mountains, very grueling event. And firstly, I, I, well, I'm thinking about their carbohydrate intake as you can, you can compare this to the recommendation shortly was 3.4 g per kilo per day. So may, that might not mean much to you, but we'll see it's pretty low, pretty poor. Um And when we, when we sort of, uh, crossed that to, you know, health, just general healthy principles of eating really poor. Like h, like a lot better than average Australian or American, but only just, and they're burning so much energy. My hypo is, they don't care if you, if you've been out for a train run all Saturday, then half day Sunday you got so much energy come home. It doesn't matter. Energy wise if you have a pizza, if you have a Snickers bar, it doesn't matter. You go the next day, train or burn energy. So the diet's poor and if they do this for 1015, 20 years, I'm worried that that perhaps might have negative health consequences. So, yeah. Alright. So this is definitely revision. I'm sure for all of you who've done anatomy physiology. I know I teach you some 8150 but something that you don't. Well, I don't use too often. So I I forget it myself. So it's nice to refresh. Here's all the structures of the human digestive tract. I'm not sure if you had this light. I took it out. I can't remember. Um, we'll go through it in a minute but just before we do a question for you, the majority of digestion takes place in there and the majority of absorption takes place in there before we enter that. What's the difference between digestion and absorption? So that's it. They bring it in about 40 minutes of the question. They're easy, great thinking. I didn't know I was talking to me. Yes. So the suggestion is when you think in the context of carbohydrates going from those polysaccharides into the dye to the monosaccharide, so we're breaking them apart. No good, breaking them apart if we can't absorb them. And so what's the answer to this question? That's what do you think? Stop in, in, it's, it's close. But no, that's, that's perhaps depending what nutrient and, and component you're looking at maybe true to some extent. It depends how we define this as well. But the actually for carbohydrates is actually small intestine and small intestine we'll get, and we'll get to this in a moment, I suppose though. Yeah. So I suppose it depends which, how we look at this question. A bit of a trick one. It's from my textbook. You could po possibly argue if you had a banana, very carbohydrate rich and you put it in your mouth and you just chewed it and chewed it and chewed it like that's, that's a lot of, a lot of breaking it down depending how you look at it. Um And it does happen through a little bit, starts in the mouth, we'll go through here. Um But as we'll see in a moment, a lot happens in this small intestine. So this, I'll put this um slide of this picture directly from me 150. But this is a nice summary. Not everyone probably will have done carbohydrate absorption um or digestion. Well, let's have a look at it here. So we'll notice firstly that there's two sides on the left. We've got starch. So this is um the polysaccharides that we're able to absorb. And then on the right, we've got the, the dietary four fiber where we almost can't absorb like the entire component. So let's look here. So it starts at the mouth. Firstly, it doesn't say here, but we could argue that digestion where we said it was the breaking down of foods or p palys or food into smaller pieces that happens in the mouth to start with by chewing. So that we can probably argue, we start there. It doesn't say here. I don't think that we could argue that but we do have an amylase which is uh where we're breaking down carbohydrate, salivary amylase which starts to break apart those that starch into smaller polysaccharides, perhaps some, some MTO. So it's starting in the mouth. Let's follow the starch down. Now we get to the stomach. Um so the stomach inactivates the salivary Mlas halting starch digestion. So that, so we said, I know we said before that the stomach might do a lot of di di digestion for carbohydrates. But this is one of the reasons why it's uh it doesn't. But then we get on to the small intestine and we can see the box is really big here. So this is perhaps where most of it's happening. We've got, now we've got a, an amylase again. So amylase are gonna breakdown carbohydrates and this time it's coming from the pancreas. So it's probably breaking um those polysaccharides down further and further. Perhaps you've got some disaccharide occurring. Now, then if we, we continue on with the pancreatic pancreatic elys is doing its thing um on the, the polysaccharides and then we're gonna get to our diacide um on the surface of the intestinal cells, um hydroly the disaccharide into monosaccharide. So then we've got down to our small units. So that's important. It happens here on the surface of the small intestinal cells. So once we get to those disaccharide, the the surface of the small intestine is able to break those disaccharide apart. So that's the answer. The reason why the answer was before that um digestion occurs in the small intestine predominantly and also absorption as we'll see in a minute. So on the surface, we get to the, we can see here that essentially we're getting our disaccharide down to our monosaccharide. In the small intestine, we haven't absorbed them just yet. But this is the digestion component over here with the dietary fiber. Um we can crush it up in our teeth, we can moisten it up which starts the process, but we don't really absorb anything. We're breaking it down for sure, not nothing digested in the stomach just yet. And fiber says delays gastric empty, which if we think about sport exercise, we don't want to be running around, um, with a huge volume of fire. But, you know, stomach is gonna slow absorption down. We get to the small intestine, but it says dietary fiber is not digest, digested delays, absorption of other nutrients. And then, so that's, that's a consideration for running around in exercise at sports. But then also when you get to the large intestine, it still mostly passes through the large in uh large intestine intact. Some dietary fiber, not much can be a somewhat um digested and uh well digested by bacterial enzymes, creating short chain fatty acids and gas. So when I told you about the, the lab that we're going to do, um and I'll show you an experiment coming up, you can test how much of a food or carbohydrate. You ha you have absorbed. Yes, looking in the blood, we can, we can do that easily. We've probably done that before if you exercise science, perhaps others as well. Um But we can also test the malabsorption of how much you're not absorbing via the hydrogen gas expired. And that's because of the bacteria in the large intestine. They're gonna uh be able to uh access that cos this has been undigested to a large extent, not absorbed, gets a large intestine and the bacterial enzymes can work on it, creating those um creating gas. OK. So now we're looking at uh a close up of the small intestine. So let's uh just orientate ourselves. We've got vila here. So they're finger like projections coming in from the small intestine and there's a micro vla which are even smaller than that. Um But this is just an overview. And so the, what's the purpose of the villa here in the small intestine? Well, there's got a couple but what's probably the main one? Yeah, perfect. So increased surface area. So if we just had a flat uh small intestine, our service area, just say this much. If we had fingers like this in that same area, it's huge. And then if you have some more smaller ones still even bigger, so we want to increase the surface area so we can optimize maximize the absorption of what we're eating. So we've got our cells here and you'll notice what I find fascinating about the small intestine is it's only one cell thick. So there's damage it can cause uh big issues cos it's only one cell thick. It's not much protection really. Um That's why there is mucosa. And so these goblet cells can help um produce mucus and mu mucus for protection. Um But one cell thick, the the benefit of that is absorption can be done quite efficiently because there's only one cell thick, we don't have to transport too much around. So I suppose we should see here if the one cell, if we have food sort of transport here or we can think about our issacs monosaccharide. They come here, they only have to get through this cell and then on to the other side and they get uh transported into our bloodstream there. That's when we can use it. There's also, you will also notice the lymph um system here as well. So some fats, particularly large fats can uh get transported into the lymph um system. Um but we'll get to that when we cover fats. But in terms of carbohydrates, we, we'll have a look at this a little bit more now. So this, so here we are carbohydrate, digestion and absorption. So we've already done the digestion part. We've said that we consumed carbohydrates uh in starch. Um predominantly here we start breaking them down with our salivary amylase. Then we get to the small intestine, the pancreatic emal ase can can also help. We said when we get to the, the surface of that small intestine, usually we're at the point of disaccharide. So we've only got um two sugar units remaining and on that surface of the small intestine, that's when it can uh break them up into our monosaccharide. And so that's what we want to do. So, here we are here, we're gonna uh look at what happens if we absorb it. So firstly, I, you don't need to know this in. Well, I suppose you do this is fairly important from sports nutrition because the first thing we'll notice is that if we have glucose comes in this way, we've got fructose coming in somewhere else. So that's important because if we're doing some sort of physio activity, um and we want to maximize the amount of sugar that we can absorb or monosaccharide that we can absorb. Um having two channels for that is probably better. And so if I was gonna make an optimal sports drink or gel, that's why there's glucose and fructose in there, cos I use different um transporters to get into ourselves. Um So we can utilize them. So that's gonna, that's important. I suppose. Uh you, you may have learned that before and you may have done a lot of physiology, but in sports context, that's gonna be important. And so, and that's one way training can uh well in a, in a depending what we're eating, but also what we're doing, we can probably uh e express more of this um sodium glucose transporter here. So that's an adaption we can have from training. So we can get more uh sugar into the body. Same if we've got five transporters. So that's a transport protein that we could change, that could uh adaptation. So we could take more sugar in which perhaps improve our performance. So what happens here? So glucose, so we noticed that the two monosaccharide here have got glucose and Glat tose. They're coming in through the sodium glucose transporter. So that's the first thing we should note. Let's have a look at the key. So we can see if we come down here, secondary active transport. So what happens is generally the sodium is going to bind to this protein here which increases the affinity of um of glucose um to enter the cell goes uh across the concentration grade or with it. Sorry, it says higher sodium uh in the lumen here, the digestive tract compared to in the cell. So that's gonna then come in. But then what also happens is we u we if we think back to our energy systems lecture, Greg said that when we absorb um carbohydrate or or then we use uh a little bit of A TP. So here we are here, the sodium potassium um tr uh pump here. So we do when that happens to get the concentration back to normal, we've got to pump sodium out. So that also happens. So when we uh in, in uh absorb glucose or glas sodium blind here comes in and then so does glucose. But then we've got to get that sodium out and we do this um by the A T the sodium potassium A TP um pump down here. So that's one sort of pathway we get glucose and glutose is in if we think about fructose. Now, the other one we can come here and check out the, the care here. So it's got facilitated diffusion um down here. So we don't need um any energy to get it in um And when it gets down to this stage here, we've got our g all of our glucose glucose fructose into the, the cell. Um And then it's gonna come out here again by facilitated diffusion and see the pump by the glute two transporter and then into our um blood to uh which can potentially elevate our blood sugars. And then we can use that for, for work. OK. This was uh this is posed in your textbook. So you can definitely check this out. Uh It's the, I think it starts your chapter that I copied it ac across into here. But I think it's kind of nice to sort of see where we're at in uh with our knowledge, we might have done some of this already. But let me give you just a couple of minutes to have a think about this question. It's only good question. So it's only then to get the concentration um back to equilibrium. Can you, is that, does that answer your question? So it's not nothing. No, it's not to do with digestion. We've already got it into the, into Glyco that's getting it into the cell. So not to do with digestion. Does that answer your question? Yeah. But let's just, we might go through these, I'll go through them one by one. Some, some aren't as easy as probably true or false, I think. But anyway, the first one, the body uses carbohydrates primarily in the form of fruit sugar or fructose. True or false. Yep. I seen a few shakes to the head. Yeah, it is false. What's the correct answer? Why is it false? Then glucose? Yep. We do use fructose. We just saw it as a, a fructose transporter. We'll eventually turn that into glucose, which we'll get to soon. But yeah, it's glucose. Two sugars such as sucrose. We've talked about this table sugar are unhealthy. Yeah, we spoke about this and should never be part of athletes. So I, I think we've covered this, haven't we? We said they're unhealthy. We acknowledge that probably use too much, but there might be times where they may be beneficial. So that is therefore false, low levels of muscle glycogen. We haven't done this yet. So it's kind of going guess or a vision, low levels of muscle glycogen often associated with fatigue, particularly during moderate to high intensity long duration endurance exercise. What do you reckon? You? True, true, great. We'll show some studies too soon to um prove that four. This is an interesting one. A diet that contains 70% of total killer calories is carbohydrates. So I think our macronutrients, 70% carbohydrates will provide the necessary amount of carbohydrates for an athlete. Tricky one. Yeah. So it's pretty high, 70% of total calories from carbohydrates SPEAKER 1 and kind of a yeah, and yeah, you're like, yeah, SPEAKER 0 but yeah, so, but so it's getting up there. So we, we know that athletes need to have good uh adequate protein. We'll get to that next week. We'll look at protein. Um, but I heard also what about energy? So essentially this could mean you have s 7 g of carbohydrate total for the day and therefore 3 g of protein for the day and, and call it, call it good. Right. It's 70%. Um, so, um, so 70% is probably adequate for pretty much every athlete. I'd say we need to account, maybe, maybe higher, perhaps, depending on certain things, depending where they are, they training, etcetera. But yeah, so I suppose that one is false but it would be a surplus or enough for most athletes providing. I heard energy is, is met so good. Number five, most athletes consume enough carbohydrates daily. It's pretty, a bit of fair advantage, isn't it? Most athletes? What do you reckon? False? It's false. I, I did, I gave a hint there but that's where June's athletes. Um, that could be enough for some, but yet protein we'll see next week is, is almost met in every instance for athletes and general population. Carbohydrates are usually under consumed. So some, some answers there. But I think we went through them all. What you think we might just do probably a, a couple more slides and we'll have a break. I, I know it's, um, and more of the time we need a break and I know some of you have, um, a lab. OK, so glucose metabolism before we get into that, I think it's mentioned in week one but what's what does metabolism mean again? Just so we know what we're actually talking about here. Sorry, maintenance. Yeah, we I think we can add to that though. Sorry. Yeah, so breaking down, sorry. So all all the, all the actions of the um yeah, all the process of of adding or taking away that of catabolism or anabolism. Yep, of so now in the context of glucose here, that's what we're talking about. So I suppose if we're thinking about glucose, now our our uh monosaccharide, uh there's many pathways that it could happen. And so here's the, the main one. So the regulation of blood glucose concentration. So our body Greg mentioned last week, I think that we, we the body also wants to keep homeostasis. So keep it sort of balanced. And so it always wants to keep the blood sugar in a certain range. And so that's one of the, the pathways and um one of the, the functions I suppose when we think about glucose metabolism, we wanna keep that balance and we'll look at that soon. Uh Another thing that can, when we have our glucose, we may want it for immediate use of glucose. So if we were in a competition, we were in the middle of a marathon, um some glucose turned up, we wanna be able to use that probably instantly if we can and we looked at the energy systems last week so we can use that dep and that will depend uh like, I suppose on many things which we'll get into. So we may, if we, if that glucose does turn up, if we're in the middle of a marathon, we probably won't want to store it as glycogen. We'll probably want to utilize it straight away, get it into muscle cells and be used um by aerobic glycolysis. Of course. So that's another thing that can happen, the use of excess glucose for fatty acid synthesis. So, if we weren't running a marathon, we were sitting on a couch and we just had a huge amount of carbohydrates, 400 g of carbohydrates, we had Coke and pizza. Um Our, our glycogen was at capacity. Then another pathway of metabolism um component maybe um storing some of that glucose, then converting it into fatty acids. Another uh couple of pathways um concerning glucose metabolism is lactate. So he said that um in anaerobic glycolysis, we so we're working fairly hard here, we may produce lactate. So we may want to turn that lactate back into glucose. So that could be another sort of pathway that can happen in some instances. We may use our own amino acids may start breaking protein down into amino acids from uh glucose. Some of them are not all of them. Um And perhaps Glycerol. So if we think back to me 150 we said that fatty acids can't, the, the act, the chains of fatty acids can't make glucose. But the Glycerol component, that's a fatty acid. So it's glycerol's usually and chains of fatty acids, the Glycerol component can create glucose. So here's some the pathways with glucose metabolism. Here's the first one, we said that the regulation of blood glucose concentration is, is very prioritized by our bodies for sure. So let's have a look at that. Now, person eats some carbohydrate. Um or when a person, when a person eats blood glucose rises rises, uh providing they have carbohydrates. Of course, if they had oil and there's no carbohydrates in there, probably not the case. But if they had carbohydrates, which mostly they would um then that happens. So the body then detects what we've got a lot of carbohydrates. So a lot of by the time it gets to our blood, we've got a lot of um glucose in the system. So then the pancreas detects that uh uh or, or, or it sends, so it doesn't detect it, it sends out beta uh from the beta cells, it sends out insulin. And so the insulin's job is to essentially unlock the liver and muscle so that our blood sugar can then um get into it. If that happens. If it's done. If it's done the right thing, insulin, then we should see that the blood sugar starts to drop. On the other hand, if we drop too low. And this, what we're talking about homeostasis as, as the body cells use glucose, um, that they've all, they've got into the muscle, they've got into the liver or we're running a marathon. Um, and the body gets too low with our blood sugar. Um Then the, the pancreas can also send out glucagon and essentially, it has the reverse effect of insulin from the alpha cells of the pancreas. It tells the liver to start breaking down some store glycogen and release it in as glucose into the bloodstream and then it rises again. And so essentially, this is uh the, the same figure that we just saw, we don't have the, the organs displayed as, as nicely, but it's the same thing. So we eat here. Um We've got too much carbohydrates in our bloods detected which stimulates the beta cells of the pancreas. So, hey, we've got our blood sugars too high. I send out um insulin. We need to, we need to lower, it's too high. That's what happens. Perhaps it do we stop eating or perhaps there's too much insulin, then the opposite happens. So blood sugar is too low, too low stimulates the alpha cells of the pancreas. So to get it backup, so it always wants to keep within this um homeostatic range. That's a big priority of, of the body. Ok. So we spoke a little bit about glycemic response um before and we said that uh fructose had a lower G I response than glucose. But essentially, when we eat, we don't eat glucose and fructose as, as um individual sugars, we eat food and depending on the structure and components of the carbohydrate in the food. If the polysaccharides and the type of polysaccharide, the comp the h how much glucose and fructose, etcetera um influence the glycemic range. So, here we have apple sauce which is low, a low gr food versus orange juice, which is moderate. Um And so we can see the different response after um we've consumed the exact, so this, in this um figure here they were matched for, I'm not sure how much I was consumed, but they were definitely matched. I know. And so we can see here that the orange juice uh evokes a much higher uh G I sponsored blood sugar peaks a lot higher than uh apple source, which, which was low G I. And so this sort of concept here is important for sports nutrition as we've already sort of mentioned there maybe times where we want, we want immediate energy because we're halfway through a marathon. Do we pull out the orange juice? Probably not. But there are other foods that we, we have a high G I response and, and other times we just want a slow release of carbohydrate. And so that's the uh the G I um response. I want to ask you this cos I sort of just, just mentioned it, but all these foods contain carbohydrates, right? Rice pasta bread. But they each have a different effect on the blood glucose when we measure them and say why is this? Yep. And what, but what sort of dictates a glycaemic index? Yeah. The, the type? Yeah. So the what are there a lot of um die in there or, or polysaccharides? Um or are they, is there a lot of fiber? Is it bound up there? So it's essentially that the, the whole food component, but the carbohydrate um portion of that, how easily are we able to di uh digest and absorb um and liberate those carbohydrates in the food. And it's actually really confusing if you look at the, at a table of foods with different G I um indices. It's, it's hard, you don't, you can't really pick it. It's hard past some pasta, higher, somewhat pasta higher, some is low. It's, it's really tricky. Um And so there, there's some criticism around it, but at least for us in exercise and sports nutrition, we know that if we're having fructose and glucose that's gonna just in, in individual units is gonna pick it up really high. Um So we, we don't need to worry, you know, we're not, we will have to consider someone with diabetes who was exercising. But I suppose in its simplest form, a sports gels, like I said, we've got fructose and glucose that's gonna be a high G I, they be able to absorb it really quickly. That's the purpose of it. Alright. Let's just uh pause now for 15 minutes or so. So maybe come back. I was welcome to stay, of course, but we'll get started again at 135. Alrighty, we'd better keep going. Uh and just on that note, uh I know this this uh lecture is scheduled for two hours. Um but firstly, I'm aware that two hours is a pretty long time for you to listen to someone for two hours, but also for someone talking for two hours. So while it's scheduled for two hours, kind of go, I'm imagining we're gonna try to keep to an hour thirtyish keeping in mind that there's a lab straight after. So I've got to run that too and we might need to go to the toilet and get some food. So we always try to finish 15 minutes early um with a break in between two. So I think it's funny during COVID, the messaging was in, you know, do short media videos, 10 minutes, 15 minutes lectures, break them up, students attention spans like, yep, that makes sense. And then sort of COVID finished. I was like, alright, two hours of lectures back on. It's like, ok, so I don't know, I feel like we should have learned something from it. Um I'm just doing as I'm, as I'm told, but um that's my thoughts. So, so breaking up would be my preference and I'll try to get two hours, like 2121 hour blocks for next, next time. But this is how it's panned out for us. Anyway. We're talking about um glucose metabolism and this has got a perhaps a slightly confusing title for this slide, but it's the same thing. Metabolism of glucose or carbohydrate. Um, same, same. So, I suppose one of the, it, it depends um on many things, but I suppose at the cellular level, um we have two options. Are we going to use that glucose immediately or, or store it for later use? That's sort of our options. And that's all gonna depend on many things depending on the requirements of that cell. Which type of cell is it? So how glucose is metabolized? Depends on, on some factors here. So firstly, the cell type and Greg hinted at this in the energy systems lecture last week difference. We we, we think about glucose for the muscle, for the workings, fetal muscle, which is very true. It's sports nutrition is what we're, we're focused on. But if all cells need glucose, so we, we all need energy, all the cells. So we if we think about the different types of cells, um a red blood cell needs, needs energy needs glucose. So that's going to use that glucose in a different way because it's mostly um anaerobic versus a heart cell or slow twitch muscle, which is aerobic. So it's gonna be metabolize that pathway of the glucose is gonna be different and rethink back to the energy systems lecture. Uh that um sort of makes sense, slow twitch versus fast twitch, muscle fiber. So the slow twitch where I just said it's gonna be mostly aerobically um metabolized. It's probably more me um mitochondria in that muscle fiber type. So it's able to do that uh better than a fast twitch, which is more anaerobically focused, doesn't need that oxygen. Um So it sort of depends on the cell type which relates to the uh the enzymatic ability of the cell. So I suppose the cell types gonna dictate, I suppose what enzymes are about. But we can change the uh different types of enzymes in certain cells. And if, if we think about the muscle, which we're concerned with, if we wanted to be able to uh exercise for longer, we might upregulate the enzymes associated with aerobic um metabolism or, or aerobic gly cholic. Sorry, if a, if a glucose turns up to a, let's say a muscle cell, you know, it's gonna analyze uh do we have enough glycogen, do we have enough gly uh glucose to use immediately? And is there enough glycogen stored? If so, then perhaps it might pivot and say, well, we've got enough uh carbohydrates stored and use or we, we're gonna store it as fat instead the hormonal status. What's what's actually happening at that? That time? The fight of flight is a good one. we can release certain hormones uh in, in the flight of FF flight response, which is going to influence the outcome of that glucose. The training history, which relates to, I suppose m most of these here is gonna dictate um the outcome of that glucose. And perhaps if we were exercising any ti any one time, the intensity of exercise, how we uh metabolize that glucose. If we, like we said, if we were going 100 m sprint and that glucose turned up, then we can't, we probably can't use that aerobically. So we'll probably try to use it anaerobically during that spring. So many things can in many different pathways that, that glucose or carbohydrate can take many variables. Um Some of which are stated here and here is how it actually is um metabolized. We went through, I'm not gonna go through it cos Greg who went through it last week, but essentially we've got our, the anaerobic part at the top and then we got when oxygen is present, we can uh use the citric acid cycle. OK. So use of muscle, muscle glycogen during exercise, no surprises. But here's a graph to show what happens. So this um this is from your textbook, but I'm not sure if it's a, an athlete or a group of athletes essentially exercised at a fairly high intensity, let's say 70 to 80% of their max vo two um for an hour and every 15 minutes, we tested the muscle glycogen concentrations and this is what we would expect to see. There is definite research and papers, we can chew um for this, but essentially the muscle glycogen depletes as we exercise at a moderate to high intensity. And we'll look at a few studies highlighting that now, actually, or soon. Ok. So here, here's one, this is what hap is this, what's happening the muscle glycogen during exercise. I'm gonna go through it slowly. Um Cos there's a bit going on in this slide. A lot of words, too many, but we'll go through it in, in some a figure here. So the first point, the effect of different exercise intensities, lines on the same graph. So let's have a look at that. So each graph over here, each, if each graph here, we've got um a group of athletes, this is from a study. We can, you can uh read it if you, if you like working at different intensities. So triangles upside down 40% max via two and we've got 70%. The triangle. Is it the right way up 100 vo two max and then 100 and 30 V two max. So each line on each graph represents different exercising sensitive. And then each figure A B and C, we've got different concentrations of stored muscle glycogen. So we can see in figure a, all the athletes here started off with 400 units of uh Glycogen in figure B, they started with 600 in figure c 800 and then they worked at different intensities at that stored muscle glycogen levels. So let's see what, what, what this slide is saying, muscle glycogen use increases with the intensity of exercise. That's the first point, definitely takeaway. So if we're, if we're working harder, high intensity, we're gonna use more muscle glycogen and we can see that from this study. So let's just for this to make this point, muscle glycogen increases with intensive exercise. Let's just look at the guys working at and girls 100% and 100 and 30% here, which is the squares in circles, you can hardly see them. But when they're working super hard, there's a sharp drop down from like 400 down really quickly. So time is on the X axis here. And, and you can see that they're really steep cos they're working really hard. Muscle glycogen is going down. So that's the first point to takeaway. Interestingly though fatigue at high intensity exercise. So 100 and 100 and 30 va two max aren't associated with low muscle glycogen stores. Why do you think that could be different system? Mm Yes. And, and yeah. And, and, and a by product of that is Y Yeah. Kind of what else? I remember Greg last week said lactate, what isn't the reason for fatigue? But something else was associated with that? Hydrogen S Yep. So you suspect here that the fatigue, that acid build up rather than low muscle glycogen would be the uh the factor here in these instances. However, at 70% vo two max, the point of fatigue is associated with low muscle glycogen stores. So let's have a look at that just to make the 0.70% vo two. So if you come up here, triangles are that way up, we can see here that so this er this um an error bar this here shows that when the fatigue was about to happen. So we can see this person working at 70% the muscle glycogen depletes, the depletes, depletes and some individuals fatigue somewhere around this 100 minutes when they started at seven, at 400 units of Glycogen. Somewhere around here, if you look at the 600 same thing, they were exercising and somewhere around here they fatigued and for S for S figure C, they started at 800. The muscle glycogen is going down, down, down, down and somewhere around here they fatigued and that is associated with muscle glycogen cos it's a different system they needed to, they were using that muscle glycogen in figure C when starting muscle glycogen stores are at the highest. So we started with 800 here time to exhaustion at 70%. Vo max is extended in comparison to figure A and B where starting muscle glycogen stores are lower. So let's have a look at it cos this is a this translating is a super important component of sports nutrition. That's why we say we need to maximize muscle, muscle glycogen. Here's some evidence, here's some proof. So let's look, here's figure C, they started at 800 we've got time on the X axis going across here. So these are the same athletes, similar condition to B and C. But if we look here, we've gone almost 100 and 75 minutes working at 70%. Where if we start at 600 units of stored muscle glycogen, dry mass, we've come across here, it's less, it's closer to 100 and 25. If we come up here where they're half about 400 stored muscle glycogen versus 800. When they started, we think about 100 minutes. So when we're using the aerobic system, 70% we're gonna use that muscle stored muscle glycogen and it is associated with fatigue. I should point out cos I was confused when I first was reading this study. You, I thought, why aren't the participants at 40%? So they might be walking. Why aren't there? Why uh, they not be able to exercise for a lot longer? But they just didn't measure it. The, the researchers said we're not gonna measure, measure 40%. If we go to max us walking, we know you can walk all day. We're not gonna test that. They did test the 70% ones in this study. So we can see here that, yeah, just to highlight this is very important, stored muscle glycogen extends time to fatigue. Of note, important adaption to uh endurance training is increased ability to store carbohydrate glycogen in the muscle. I think the next slide is gonna show that. Yep. Um And I just noted that time to fatigue was only estimated in the 70% vo two max. This study's actually come from a meta analysis. Um So it's probably a good one to read if you're interested in it. Ok. So this is from, I think the same study. Um 22 very important points to take from this one. Muscle glycogen content varies depending on a both athlete diet and training status. That is what this slide is depicting and super important. So let's have a look at that here. We've got different athletes at different fitness levels or we can say vo two max or fitness levels, similar kind of concept someone with at a vo two max of 40 mils per ki. Uh So this, this group here is able to utilize 40 mils of oxygen per kilogram per minute. And so we can see their capacity to store muscle glycogen is less than someone who's a bit fitter and it's uh less still to someone at 60 less still to someone at 70. So that first point as you get fitter, your ability to store muscle glycogen increases. So that's the fitness part. But now let's look at the diet part. So within that, let's look at the 40 vo two max first, this is showing that um the muscle glycogen concentrations under conditions of low normal and high carb carbohydrate availability. So, if someone was reducing their carbohydrate for uh for whatever reason, they, and they had a, a max, we two or 40 then they could only store about this much um muscle glycogen if uh a normal levels here. But if we did some carbohydrate um loading, then you can uh it, it increases further still. So that's the other thing that the important thing that this graph is showing is that if you don't consume much carbohydrates, we can see that in the white, your capacity to store muscle glycogen is, is reduced versus uh a moderate amount versus a high amount. And so that this is important, then if we think about what advice we may give athletes if you have a recreational athlete who, you know, is not very fit they or less fit, perhaps, let's say 40 vo two max, they just go for a Sunday run for 40 F or for an hour and a half. And then a Tuesday run, they don't need to consume as much carbohydrate as someone who is really fit cos they don't have the capacity to store it. So you wouldn't go away when you look at carbohydrate guidelines. And you know, the recreational athletes say you need 12 g of carbohydrate cos that's we want to maximize those glycogen levels, the fitter you get, the more you're able to store and therefore the more aggressive you may want to um advise someone to consume carbohydrates. Any questions about either of those graphs because I that they're two, just two studies and two slides. But I think they convey a pretty important sort of message, particularly when you're considering carbohydrates. So I suppose when we think about um carbohydrates, we often think about endurance performance um because it's the aerobic system, which is definitely true. But here is a, a nice figure that that now shows our muscle glycogen uh concentrations, different sports. Um So cycling, cycling of course can be an endurance sport, but here there was just five minute efforts. So even when it's more anaerobically um based, we still reduce that muscle glycogen uh levels triathlon, 70.3. So a half Ironman, probably unsurprisingly that usually takes somewhere between probably four and 10 hours depending on who you are, how trained you are. But no surprises there for endurance based muscle gly, it drops considerably but during strength training, same thing rugby league. So team sports, uh a swimming six K probably get no surprises there. It's more uh in endurance or aerobic based activity. But importantly, like we just, we said, starting Glycogen concentration depends on the training status. So as we get fitter, we're able to hold more muscle glycogen. But then also from the dietary perspective, what we're concerned about in this unit is that precise dietary carbohydrate intake. And we will look at strategies, I promise about how to maximize those soon. And so before we do that, I think this might just be the last slide before we get on to actual, you know, ranges and recommendations. But how much carbohydrate we actually use the oxidation rates, I suppose depends on many things. But two main ones. Firstly, uh total energy expenditure. So uh your exercise intensity and body mass, someone who's exercising at a high intensity with a bigger body mass is gonna burn or you utilize a lot more carbohydrate than someone exercising at a lower intensity and has a lower body mass. And then I suppose the proportion of energy derived from carbohydrate then depends on a few things. So, is it available, did they have um stored glycogen available? Was it low? Is there any uh carbohydrate coming in during that activity? What is the habitual intake of um carbohydrate? Cos that's gonna influence it. We've already, we already know that training status influences it and exercise intensity as well. And I'm sure all of the exercise science students will have looked at this a lot, but we can um determine the amount of carbohydrates we're utilizing uh during activity. And we were going to do that in the, the first lab actually. But due to a few circumstances, we didn't. But if we do get um access to a megabyte cart, we're able to assess how much oxygen we're taking in. And the CO2 expired, we're actually able to determine the amount of carbohydrates we're burning. And so there's some tables that have been derived. So the respiratory exchange ratio um is here and we can determine this using a mobile car. Um But essentially if that comes out to 100 to 1, then we're using almost all carbohydrate. Uh We, we don't have time to start to um use that fat because it's a longer energy pathway. Um And so eventually we'd have to probably slow down. We can't sprint at a, you know, the hardest forever. Um We'd eventually have to slow down and then fat would start to come into play more. So, but uh we can actually calculate these uh from indirect calorimeter. OK. So this graph here will show that in red, this is someone or a group of people consuming a carbohydrate. Um I'm not sure if it's a gel or drink or whatever it is, they're consuming carbohydrates during exercise in the red here versus someone in the blue, not consuming any carbohydrates. So, in this instance, in this graph, it's showing that muscle glycogen is getting depleted regardless if you're consuming carbohydrates during that um activity. But the big difference and this, the big difference here is that the person who was or group of people who are consuming carbohydrates, the time to fatigue is greatly extended. So this was to this study was to fatigue. The people who are not consuming any carbohydrates, cos I having the placebo with no carbohydrates, they could not go any further than three hours. Whereas the group consuming carbohydrates um during that event was able to extend that by an hour. So that's a, it's a big um outcome of carbohydrates. This is during exercise, bit going on in this slide. But it's a, it's a nice one I think. So, this is showing high carbohydrate availability acutely. So these are these, this is a, a meta analysis has conducted. It's AAA nice one to read if you're interested in this. But it's basically collating all the studies that looked at uh carbohydrates being uh compared to a placebo. So it might be, you know, uh a gel versus a gel without any carbohydrates. So basically carbs versus no carbs. Um and the increase um in performance carbs versus no carbs, we can see uh to explain it a little further. We've got single source of carbohydrates and multi source of carbohydrates. And so the single source is probably most likely gonna be where they've used um just glucose, no fructose and the multi source, um they're gonna be using glucose and fructose. So we can see um this, so this is the correlation essentially um when we consume carbohydrates as a as a correlation for um for total exercise time, I suppose. Importantly, I sh I should also mention that in these studies, um they were undertaking a time trial rather than time to exhaustion. So not only for this graph here, it shows that you, you should be able to go longer if you're consuming carbohydrates um during activity. But this one here is indicative of performance. Um So time taken to complete a time trial. So what that means is let's look at them. So the total exercise time. So if in this instance, in these studies, the researchers have probably said, right, I want you to complete a cycling event, a cycling time trial. Um It's, let's just say 15 kilometers, you need to go as fast as you can. And so one time you have carbohydrates and one time you don't, whereas up here it's asking you to go for uh for uh but uh three hours. So it might say you need to complete 180 kilometers on the bike. One time, you get carbohydrates one time you don't. So he this uh bar graph is it collated? So in exercise, that's under an hour where carbohydrates are consumed, the versus not, there's an approximate 2 2% 2.2% increase in performance in terms of time. So that's very beneficial if you exercise or, and this is for s single carbohydrates, I think for exercise or maybe collective for exercise. That's 1 to 2 hours where you're performing a time trial, you get about a 5% ish um increase in performance, consuming carbohydrates whilst exercising um if it's longer than two hours. So this is where we've separated between single source and multi source. It's approximately again, uh 4% f for longer than two hours. But where the real benefit comes in here, if it's, if you're doing an event, which is, which is more than two hours and you're having glucose and fructose, it's almost a 10% uh time and per performance benefit there. So that's, that's pretty huge. Training is super important. But you know, if you get your nutrition wrong in some sort of endurance event over two hours, then it can really cost you 10 percent is massive. Any questions about this graph, it's probably one where you can go away and read it and try to interpret yourselves rather than someone talking through it. But um it's definitely a good one collating all the acute studies and time child performance with carbohydrate versus not carbohydrate. OK. So that was that, that slide we just showed, looked at the acute um differences in performance. Uh And this study here is a great one. It's, it's a bit old, but it's great. Um Looking at what happens over several days, perhaps, you know, if someone's training load. So I'm gonna try to talk you through it a bit going on. So runners undertook an 11 day train block consuming either 5.4 g of K uh grams of carbohydrate per kilogram per day or 8.5. So we call this one, I think this is called the control and this is higher carbohydrate. We can still get way more than this, but this is, this was deemed high in this study. So on days, 158 and 11, so this, this uh figure here represents that 158 and 11 indicated by their grading runners completed a lab performance test. So they went into a lab to do this. So it was really controlled um with easy training days on 234, here's 23 and four. So white means easy and hard training days on 679 and 10 indicated by squiggly lines. So essentially it was 11 days training block, then they had 10 days to wash out and then another, the exact same 11 tray days um on the on the opposite of what they'd consumed. So they might have a group might have started on high carbohydrates in this instance, wash out and then on the low carbohydrates. So it was a crossover design trial and let's look at what they did. So in this lab trial, in the, remember, this was the shaded gray, they did 30 minutes at a about 60% vo two max. So that's fairly easy jogging. Then they did 30 minutes at about 75. So fair, fairly uh moderate. Um And then they were asked to do an eight kilometer time trial. So as as um as as far as they could and you know, um eight kilometers do it as fast as you can. Sorry. But so that, that was the, that was the great parts. So they did that every, they did that a couple of times, four times and they won five and eight and 11 here at the start. They did easy training and then hard training days here. So essentially they did a baseline test, had a few easy days and the back half they went pretty hard on the hard training days, squiggly lines, 16 kilometers all out effort. So this back half is, you know, pretty much a week of gone, all out every day, pretty intense. So let's see the results. I'll try to put this together. So let's look at what that would look like if you're having, if you had a, if you did a test at the day one and then you kind of did easy training, just sort of um 60 minutes, not too hard. The effects of not having a high carbohydrate probably wouldn't, you know, it amount to much, you might hypothesize. And I suppose that's what we, we saw. So this uh figure here shows the trial days whoops, the gray periods where they came in worked kind of easy, jog, a bit of a harder jog and then they had to do eight kilometers as fast as they could. So at baseline, no obvious there's no difference which is probably as expected on day five, no difference between high carbohydrates and low carbohydrates, which is probably as expected because the days preceding this were easy days. So they didn't really need to maximize their muscle glycogen or have carbohydrates. So that's kind of as expected. However, when the hard training kicked in and they were trying to run 16 kilometers as fast as they could every single day when they came back to the lab to do the test, We can see that the high carb group did much better than the low, the control group or low carb group. And that was just even more exaggerated by the final day. So training in a state of low carbohydrate elicited uh you know, inferior time trial results in this study. That's what in this study in this part. That's what this figure is shown here. We can also sort of see what's happening during that speed during the 16 K run. So remember we said these squiggly lines here is when they weren't in a lab, but they were just asked to run as, as hard and fast as you can for 16 Ks, we will time you. And so this is what they found here on those hard days at the start after their sort of easy training. Few days, there wasn't too much between the high and high and low carb group. A little um bit more pronounced on day seven. But after a couple of days, training in that low carbohydrate state, we can see here that now it does become significant and the time taken to do that 16 kilometers whilst it wasn't tested in the lab was still very different. So this shows that the, you know, the chronic uh effects, I suppose or evidence for consuming carbohydrates during training, there's definitely times we may want to manipulate that and we'll get to that soon. Um But th this is a nice study showing what happens after a high, you know, high training volume. Hi, all that effort. What happens in terms of your speed? I think is very interesting. I found. So then there has been a, a bit of a phase perhaps, maybe a couple of years ago, but still there, there's the, the low carbohydrate availa availability or low carb, high fat diets for athletes. Does anyone have any thoughts on this before we go into it? Does anyone think that's a bad idea? Good idea. Perhaps sometimes never. SPEAKER 1 I have a lot of black boy goods kind of do that so like eat so that I can eat less food but still good food. And I have, yeah, I suppose in the, in the SPEAKER 0 context of endurance athletes, I assume. But yes, so when we get to um yeah, hypertrophy, athletes and body builders, they definitely manipulate like super high protein. Yeah, low carb, but at the same time, we did see that muscle glycogen decreases um for, for many sports depending on what they're doing so they still might want to have some carbohydrates potentially to get, um, a maximum, uh, training session in at times. But that's definitely something we'll get to for sure. SPEAKER 1 I like steak. Um, butter. Yeah. And then like, the only sort of cards they have would be like some fruit, some honey. That's about it. But otherwise it's like steak butter eggs. SPEAKER 0 Yeah. So it's, it's fairly popular. Social media is big, big, Um Any other thoughts on this? SPEAKER 1 How soon they, where do they go into? Did she let you stop breaking it down as an insurance athlete? SPEAKER 0 Yeah, quite, quite potentially depending on what you're doing. Yeah. Yeah. So the, so the theory, so there is some definite benefits for this. So we'll have a look at it. That's a, that's a good point. Um The, the idea and theory behind it is you, if you have a low carb diet and you're training as an endurance athlete or any athlete, really, you're trying to shift the up regulation of fat ox oxidation um higher on that vo two. So remember if I showed the uh respiratory um let me just pull it up. So here where we start to um uh stop oxidizing fat, we kind of wanna shift this um up so that we're using up, we wanna shift this so that we're able to use fat more than carbohydrate. So if we can exercise at a higher intensity, so let's say we need 80% 90% max two. And we're predominantly using fat rather than carbohydrate. Then eventually we might have to use that muscle glycogen. But if we're able to utilize fat, we've got an infinite supply essentially. Um Then that's sort of the main theory behind it, which actually isn't too bad as we'll see in a minute that only come like that would be beneficial and SPEAKER 1 low intensity. SPEAKER 0 Perhaps the fear I show in a minute. It yes beca because you can't use fat at that high intensity. But the theory is, if you train more often in that state, then you're gonna be able to change the pathway. So you're able to exercise fat um to a to a more to a to a greater extent. So that's, that's the theory behind it. We're trying to shift that part, the, the intensity we're able to um burn fat essentially because mu muscle glycogen is limited. We just showed what happens if, if we're trying to do intense activity, we ran out of muscle glycogen, we fatigue. If we able to utilize fat, it's unlimited and we can use that pathway more effectively. That's gonna be a good thing. So that's the theory behind it. Therefore, less carbohydrates are needed during activity that's gonna be good. So these are the, the theory behind it and I I go into this in some detail here, but there is part of your assessment uh for the media campaign, one of the topics is gonna be this. So you can uh explore this definitely more. Um another benefit potentially is that fat as a substrate produces more energy per gram. So everybody use those fatty acids, we can obtain more energy per gram. Um can train at lower carbohydrate intake without training. Um without influencing training intensity could be also useful for reducing body fat and weight if we get, if we're using our uh fat. So that, that therefore we may be able to reduce body fat if that's the goal of an athlete. So that's sort of the theory behind it. Um, but we just saw as an endurance athlete from that study previously, it's probably not a good idea to do that all the time, but we might, we might finish in a slide or two, but I just want to show you this. So this study's great. There's only, um, tw uh 10 people in this study but hasn't been, um, too much done here. So, what this study do was, was a low carb, high fat diet. So the 1st 10, people was, was consuming a, a high carb diet. So about 60% carbs, 15% protein, 25% fat. So it's kind of just like a, a normal everyday sort of a diet. Then we have the, the low carb group here. So they're only having 10% carbs to 20% from protein and 70% fat. So, mostly consuming fat. Importantly, they're on this for 20 months. So in this cohort, they should have had that time for the adaptations to which will go too soon um to change. So we should be able to see the differences in um fat and carbohydrate substrate utilization what they're burning during exercise. So, let's have a look here, here's, here's the athletes during uh this, this group here during rest and then they start um exercising here. What intent? Uh I can't remember what, so 100 and 80 minutes running at 65% vo two max and then 100 and 20 minutes of recovery. So they, so they're exercising at 65% max birds too. Here, we have the circle group, which is the low carb group. Uh So the low carb, they're not consuming much carbohydrate and lo and behold, they are burning a lot of fat. So they were able to influence their um fuel substrates to, to mostly fat. Whereas the carbohydrate uh was not as good as that. We should expect to see then the opposite if we're looking at carbohydrate oxidation. So the triangle group, if we see that um this is the, the high carb group. So the, the people who are consuming high carbohydrates all the time were in fact a burning carbohydrates during that exercise. So this, I suppose um provide some evidence that depending on what we eat, we're able to shift what substrates we're, we're burning, that could be beneficial because we just said that for these reasons here, that could, that could be nice if we cos we have unlimited fat essentially versus muscle glycogen. So, if we're able to burn fat during exercise, that's gonna be a good thing. Is this gonna be optimal? We just saw in that study before that, possibly not because, uh, in this study here, we saw that speed was reduced in, um, on the low carb diet. And the research overwhelmingly does show that but there maybe times if we could get this, achieve this without doing this all the time going on a low carb diet, um you know, just in everyday life, if we could somehow manage that, um and get these responses and that would be beneficial. And so that's one of the big concepts. Um I'll go into it later. That's one of the concepts of here. So we might make two more slides today. So we know that we can cha uh have metabolic adaptations within SCLE of muscle in highly trained athletes at sub maxim work rates. So here's some ways that we can um to have metabolic adaptations to enhance our performance. And some of the, a couple of these feed into that um oxidizing f having a better efficiency at oxidated fat. So let's have a look at them. So increase cap. So someone who is um fitter is gonna have increased computerization, that's good because we can get more nutrients, we can get more oxygen to the working scooter muscles gonna have uh uh mitochondrial uh density, which is, I suppose the same as the number. So, the mitochondria, particularly in aerobic, um slow twitch muscles are gonna have more mitochondria. They're gonna be more efficient as part of that. There's, there's gonna be enzymes around that can uh help oxidize glucose as well. So, a change in enzymes that are about gonna help us um with a adaptations at submaximal work rates probably gonna get better at lactate oxidation as well. So if we're burning, uh if we working anaerobically and we have the lactate as a by-product where again, the more we're trained, we're gonna be able to um use that lactate for energy. We're gonna have uh increased concentration of transport proteins. So perhaps an adaptation there as I showed at the start on the uh small intestine, we had the different transporters getting glucose and fructose in. So we might upregulate those but also to get those glucose into working scooter muscles, there's proteins involved there, very similar ones. So we might upregulate those as well. We have a, a better ability to store muscle glycogen concentrations and liver and as we get fitter, the ability to meta metabolize fat as a substrate increases too. So on the concept, then of a low carbohydrate, high fat diet for athletes, we can, if we do that, we, we might be able to change the ability to metabolize fat as a as a substrate, we get better at it. And that maybe through various um enzymes that are about. So we're able to use that fat pathway a little bit better. We will look at this when we get to the fat lecture. But that's uh you know, if we could do that, that would be good if we want to get better uh and have those adaptations. So um those metabolic adaptations at sub maximum work rates and increase or change some of these, there's a theory called the glycogen threshold hypothesis. And essentially that is you either need a f well, I'll read it exactly word for word. Um So training with low carbohydrate avail availability, enhances the metabolic adaption to exercise. Research suggests that it's the postexercise glycogen concentration that influences the level of adaptation that occurs according to the glycogen threshold hypothesis. So, here's some studies showing that there's a, a way to get this threshold to under 300 millimoles of kilogram, dry weight, um Glycogen. So if you exercise and get in this range, we use iron muscle glycogen, then the body thinks, 00, we uh we're exercising at this intensity. They've got no glycogen left, we better get better at storing it. We gotta get more efficient. The way it does that is it changes some of these things. And so I suppose when you think about low carbohydrate diets, they're always gonna be in this state. So the body thinks right, we're gonna have to get better at this because um there's never, there's never much mice or Glycogen around. So that's why the, we get better at metabolizing fat. We have different um carrier proteins, we have different enzymes about. However, this might make this the last slide, but it's an important one. You don't have to go on a low carbohydrate, high fat diet because as we saw that's probably gonna be detrimental. It is detrimental for particularly endurance, but perhaps other team sports, etcetera as well. But there are other nutritional strategies that could be employed. And we're going to have a go at this in the tutorial um starting next week, uh A and B starting next week. For example, if you train fast and you get up, you don't have breakfast. Um that is a way then to help achieve the um this the threshold here, the glycogen threshold hypothesis. So if there's no carbohydrates, you're gonna have to get better uh utilizing um fat ox oxidation. Another way could be no carbohydrates during training. So this way you might wake up and have breakfast. So you've got carbohydrates in the morning. But then during activity, you say you're working for an hour, working out for an hour and a half, two hours. But during that time, you don't have any carbohydrate that might get you um those adaptations as well. Another way is it's called delayed rescue. So that could be, you do a big workout. You might have carbohydrates during that activity. It's an important workout. You wanna, you wanna go in really hard intense sessions. So you have carbohydrates during, but post training, you only have protein, no carbohydrate. So then your body has to adapt as well. Another way it could be training twice daily with the second session of carbohydrate. So again, you might have breakfast in the morning, you might have carbohydrates during your first session. Uh But then in the second one, you, you don't have any carbohydrates, post your first exercise. Um And so you're training in a state of low carbs for that second session. Another way it could be sleeping low. So you, you, you may have a low carbohydrate intake for dinner, wake up the next morning and then exercise there. So it's been a, a big period. You're not following a low carbohydrate high fat diet. In fact, far from it, there will be sessions if you did employ some of these strategies where carbohydrates would be super high cos you've got a really intense activity coming up. You wanna nail that training session, but there may be times where you wanna be in a low um carbohydrate state. Cool. So we'll leave it there today. We'll pick this back up next week after the quiz. Um Week five, I've sort of left it somewhat um vague. So that if uh if this went over time, then we could catch up there Alright, we'll leave it there for today. Have a good week.