Podcast Episode 86 Transcript – Nutrition For Endurance Athletes

Aidan:

Hello and welcome to episode 86 of the Ideal Nutrition Podcast. My name is Aiden Muir and I’m here with my co-host Leah Higl. And today we’re going to be talking about nutrition for endurance athletes. We do have some exciting news today as well for the rare few people who watch on YouTube in that we have finally invested in having a good background so-

Leah:

It’s not just a white wall anymore.

Aidan:

Yeah, huge upgrade. Massive win for the podcast, and hopefully it serves us well.

So going through nutrition for endurance athletes, we are going to be covering about as much as we can in a single episode. So I don’t want to make this a multipart series. So we might race through a few things, but we’re going to try and cover as much as we can. We’re going to be touching on stuff like carbs versus fats for performance, intra-race carbs and carb loading for people who are going down the higher carb route and body composition and stuff like that for performance too, as well as little easy wins like things we can do with hydration, electrolytes and some supplements as well.

Leah:

Awesome. So let’s start off with looking at carbs versus fat for performance in endurance athletes. So the consensus from our current body of research is that high carb approaches, overall, tend to be superior to lower carb approaches when we’re looking at performance in endurance athletes. There’s definitely people that make arguments for certain low carb approaches, but the research hasn’t actually found it to outperform high carb approaches in most circumstances, at least. When you think about it, this does make sense since the fact that carbohydrate utilization in endurance sports is quite high. So having a higher carb availability does seem like a more intuitive choice for these types of sports. I think it’s interesting to note as a side note, the reason lower cup approaches become… Why they became an area of interest was due to the theory that by having low carb availability in training, that perhaps athletes would then become better at utilizing fat as a fuel source.

So once we run through all of our glycogen stores and maybe we don’t have the ability to take on as much carbohydrates during a training session or during a race as we need, if we’re really good at then tapping into using fat as a fuel source, maybe overall that would improve performance in endurance athletes. So that was the theory and why these low carb approaches started to get investigated in the research. But for the most part, it doesn’t really seem to work out how the theory suggests in that there does seem to be a decrease in overall performance in endurance athletes on overall lower carb approaches as opposed to having just general high carb availability in your training sessions and in your races.

Aidan:

So adding on to that, one reason people think about the higher fat utilization potentially being a good thing is if we add some context around this, glycogen is our storage form of carbohydrate. And as most or a lot of people listening might know, carbs have four calories per gram. A lot of people also know that fat has nine calories per gram, but our body fat isn’t 100% made up of fat. It contains more than stuff like that. So a kilo of body fat contains about 7,000 calories. So 1,000 grams of fat in our body, about 7,000 to 8,000 calories. If we can store, say, 500, maybe 600, sometimes more, sometimes less, grams of glycogen in our body at the start of a race… Let’s just do 500 to make it a round number. 500 times 4. That’s 2000 calories we’ve got sort of glycogen. Even if you’re shredded, even if you are lean, you have so much body fat in terms of calories because if you had only five kilos of body fat, that’s 5 times 7,000 to 8,000.

It’s a lot. We always have an abundance of fat stored in our body, whereas we have a limited finite supply of glycogen. So going through that topic a little bit further, going about and talking about what can we do to kind of improve our glycogen utilization in a way, one thing we can do is we can take on carbs while exercising. We can take it on while racing or training or whatever. We know that glucose is the most effective fuel sources due to the research that was just mentioned and also because we see that when people quote unquote hit the wall and their glycogen levels either run out or drop quite low, their performance drops. We see this in race times. We see the splits, and the splits are getting slower and slower after that point. So one way we can preserve how long we’ve got glycogen for is to consume carbs while exercising. Even while doing this, it’s borderline impossible to have more than, say, 90 minutes worth of glycogen even while taking on carbs to the maximum ability that we’re able to do.

This is why people still hit the wall in a marathon at, say, the 90 minute mark, even if they’re doing everything. If we could improve that threshold, we would be breaking further records. This is one of the things that seems to stop people from cracking that two hour marathon kind of milestone. If instead of that happening at 90 minutes, we could get it to 110 for example, be a game changer. But yeah, you can take on carbs while doing this. There seems to be a cap on how much glucose the body can absorb slash metabolize while doing this. It seems to be at a maximum of around 60 grams per hour, but one way around this is by using multiple carbohydrate sources. If you have glucose plus fructose or a few other sources like maltodextrin or something like that, you seem to be able to get up to around 90 grams per hour, theoretically, which is a lot of carbs to be able to take on.

As I said, if you could take on more, even better. There are some top athletes who are consuming well over 100 grams of carbs per hour. There’s going to be one study we’re going to put in the show notes where I believe it was trail runners or mountain runners, something along those lines, they had 121 grams of carbs per hour.

Most people in the Tour de France have over 100 grams of cars per hour. So even though I’m saying 90 grams seems to be the theoretical limit, there’s some freak athletes out there who are going higher. The ideal ratio is proposed to be a two to one ratio of glucose to fructose, although that’s a pretty round number and we know the human body isn’t perfectly designed for round numbers. But most sports drinks and gels and stuff like that will have a ratio like that. So you can get in supplements, and you don’t even need to think too hard about.

Leah:

Yeah, it’s not something you usually have to go out of your way to think about unless you’re making your own supplements for whatever reason.

Aidan:

And one big caveat on this is pretty much nobody’s going to be able to have 90 grams of carbs per hour without practicing it first. If you get somebody who is an endurance athlete but never takes carbs on and you try and give them 90 grams of carbs per hour, they’re very likely to get GI upset. It’s going to hurt their performance. But if you start low and slowly build up over time, you might be able to get there. You might not be able to get there, but you’re very likely to be able to train yourself to be able to take on more than you’re currently capable of tolerating.

Leah:

And I find training the gut is something that most… Or at least there’s a lot of endurance athletes that just don’t know about it and therefore… Especially when they first start an endurance sport, they’ll just go straight into an event and try to consume way more than they ever had in training and therefore end up with gastrointestinal distress or just not be able to take it all on as they had intended to. So I think that’s a really important aspect that maybe we will eventually do a podcast episode on, but I guess we’ll see how we go.

The next aspect we’re going to talk about is carb loading. So this is basically a tool that we can use leading up to events to maximize the amount of glycogen we have stored in our liver and our muscles. So going back to that amount of glycogen that we can store for that 90 minutes worth of exercise, that’s talking about maximized glycogen stores. And to do that, you really are likely going to need to do a carb load like this prior to an event. So talking about carb loads, when most athletes do it without a plan and they’re just doing it more intuitively and just going, “Oh, I’m just going to eat more carbs leading up to an event,” we usually don’t see athletes getting quite enough to maximize things.

So in practice, we usually see athletes getting in around five to six grams of carbohydrates per kilo body weight per day in their carb load phase. Where we know the gold standard for carb loading is more like that 10 to 12 grams of carbs per kilo, and that’s looking at anywhere between one to three days before the actual event. So that’s the gold standard. And then in practice, we see people doing half of that. So I think it’s really important that most athletes do have a proper plan in place. And then even just thinking about the logistics of getting that high quantity of carbohydrates in, you are probably going to have to choose lower fat, lower fiber options and be very almost meticulous about your food choices. So if you’ve never done a carb load properly before, I think going to someone who knows how to do it and getting a plan is probably a good idea.

Aidan:

Almost everybody I’ve given a plan to has been shocked by what it looks like because it’s a very abnormal day of eating. You’re not going to accidentally-

Leah:

It’s very strange.

Aidan:

With body composition stuff, this is a tricky topic. This is very oversimplified, but I think when you look at pretty much all sports, there is often an ideal physique for that sport in terms of body weight, in terms of body fat percentage, all of those kind of things. It’s usually a range. It’s usually not this tight, this is the perfect physique or anything like that, but there’s often a rough range. There’s a lot that goes into that. But one thing I’m getting at with the body composition stuff is in most cases, getting leaner helps improve performance in endurance activities. I use the word most cases loosely because it doesn’t always. You can be too lean. You can be so lean that you start getting sick more frequently or getting more injuries. Your performance is dropping. There is obviously… We call it a U-shaped curve or something like that where getting leaner helps up until a point, but at some stage, it hurts.

It’s just the average person often will benefit from getting leaner if they’re doing endurance activities. We have talked about fat loss elsewhere. We’ve just done a three part series, so I’m probably not going to talk about that too much here. But one logistical challenge I think is worth touching on with endurance athletes is you’re balancing having a really high training workload where you’re burning a ton of calories, you want to be eating a lot of calories to fuel your performance so you can train well in everything like that. And often you could end up being quite hungry because you’re burning so many calories, and you’re walking this tight rope of trying to get enough calories in while also being in a small calorie deficit or a moderate calorie deficit to get leaner.

Another aspect on this whole concept of not always just striving to get leaner and everything like that is in the process of striving to get leaner, you have to be consuming a suboptimal amount of calories and carbohydrates most likely for fueling your training and performance. By definition, your training will be suboptimal while you’re in a calorie deficit because you don’t have enough calories coming in for recovery to be optimized, and you can’t have a great amount of glycogen and stuff like that all the time throughout the entire week, month, whatever. So it makes sense to have planned phases of getting leaner, ideally not lining that up with races and stuff like that as well where you just want to be going in well fueled and stuff like that.

Leah:

And training the gut as well, balancing that leading into a race.

Aidan:

That’s another thing that makes it more difficult from walking that tight rope in terms of there’s a lot of people I want to be increasing the carbs they’re taking on in the weeks slash months leading up to their race, and I don’t also want to be balancing that with trying to get leaner at the same time.

And another thing is it shouldn’t be an indefinite type approach because there’s certain athletes I see who are spending all year trying to get leaner and they’re not necessarily succeeding, but that therefore means they don’t take as much of a focus on fueling their training as well because they’re always trying to get leaner. So they’re trying to be in a calorie deficits so they’re not going to be having a bunch of carbs intentionally, but then they might unintentionally have more calories. And it’s just like you want to get leaner in a phase and then spend a large portion of the year ideally just fueling yourself well.

Leah:

Perfect. Next topic we’re going to touch on is hydration. Hydration is surprisingly simple in most cases at least. It’s basically drink when you are thirsty and then stop when you’re no longer thirsty. So I always say to my athletes, “Drink as per thirst,” and then if anything comes up that is a bit of an issue or we might think is an issue, then we’ll address it then. But typically, if you follow your body’s cues you’re going to come out okay, usually. So this is often better than a specific plan just because there’s a lot of variables. So we know that sweat rates change based on things like the weather, for example, which is something we don’t have any control over. And if you have a plan that doesn’t factor that in or your individual sweat rate or all these other things that could play a role, you can unintentionally over or under hydrate.

So it makes sense to literally just drink when you’re thirsty, and when you’re not thirsty, stop drinking. So I think something important to note here though is that research shows that losing over 2% of your body weight through dehydration does lead to a pretty significant loss in performance. So if you want to double check whether or not you are getting enough fluids in your training or during a race, you can weigh yourself pre and post and get an idea of how much weight you have lost and make sure it’s not over that 2% of body weight through dehydration.

A little bit of a caveat here though is that there are top level athletes who do lose over 2% of their body weight through dehydration in events and are still winning races. So I think there’s probably a couple of factors to this. I think in some sports, it’s the logistics around taking on fluids, and perhaps you’re spending more time taking on fluids and slowing down and then maybe urinating, et cetera, all these logistical things that are going to slow you down overall as opposed to that drop in performance you might see from dehydration. So there’s all these logistical things. So I think at the end of the day, probably don’t worry about hydration too much other than just basing it off of thirst.

Aidan:

Yeah, there’s one thing where I’d love to give people really specific protocols, but because of the weather, because of all of these other variables of sweat rates, it’s like you-

Leah:

You just can’t guess it unless you have a really high end setup where you can test individual sweat rates, exactly what the weather and temperature and humidity is going to be on the day, which in an elite level, I’m sure there are sports dieticians that are paid to go to that Nth degree and have those setups, but without all that information, there’s just no way we could put a finger on it.

Aidan:

So with a plan, you risk under hydrating or over hydrating. And with the whole greater than 2% thing, I wonder how much of that is also to do with their performance actually is dropping due to being slightly over 2% dehydrated, but it’s so late in the race that it also doesn’t matter.

And yeah, a famous example of it was in a cycling event where two people were competing with each other to win the race, and they were 2Ks away from the line, which obviously in cycling is not a lot. 2Ks goes by very quick. And one guy gets the water. He looks over to his left to grab the water, and as he looks away, the guy on the right just sends it-

And takes over. And after the race, the guy was like, “What are you doing?” It doesn’t matter if you’re hydrated for the last two minutes, just try and win the race.

Leah:

Yeah, yeah. I think that’s a good point. So logistics definitely come into play if it’s literally slowing you down to drink and you are finishing your race.

Why would you do that?

Aidan:

Yeah. So going onto electrolytes, I view electrolytes as more of a do no home situation than nailing this will improve your performance significantly type of thing. Something that’s led me to that belief, the first thing that led me to that belief, honestly, was that there’s not many people giving specific guidelines around electrolytes. Say somebody’s running over 100Ks, right? A long, long event. We know that they need to be taking on electrolytes, but it’s weird that nobody’s giving guidelines. There’s a few guidelines out there and one of them I will talk about specifically in relation to sodium, but there’s not much concrete stuff on this. And I think one of the reasons why there’s not much concrete stuff on this is because it doesn’t matter that much. You mostly just want to avoid going super low, getting deficient, all of those kind of things.

The first main guideline that is really important is to consume 300 to 600 milligrams of sodium per hour during an event. Slightly higher, slightly lower is probably fine, but that’s a good guideline that I would personally follow. And for even longer events, say, longer than three hours or anything like that, probably makes sense to consume other electrolytes as well. But most sports drinks contain enough to optimize that without you even thinking about it.

One thing I want to touch on with the sodium specifically with the do no harm kind of concept is there’s a thing called hyponatremia, which can even affect people just doing a marathon. I’m not even talking ultra, ultra endurance, just in a marathon. And it’s very unlikely to affect top level athletes because they finish the race so quickly that they’re not going to run into it. Hyponatremia is basically low levels of sodium in the blood, so low salt in the blood pretty much. The people who get it are the people who say it would take over five hours to finish a marathon. They’re still pushing hard so they’re sweating like crazy, but they’re only taking on water with no electrolytes. And taking on the water could even arguably be making the situation a little bit worse because it’s diluting the sodium in the blood a little bit. So if you are going to do a really long event, you really do want to be taking sodium on as well.

Leah:

And I think the easiest way to approach that is if you are doing a long event and you are taking on fluids, just make sure they have electrolytes in them. And most of your pre-made kind of mixes from the supermarket in terms of Staminade, Powerade, whatever you want to use are going to be sufficient in meeting your requirements for avoiding hypernatremia, anyway. Next thing we’re going to touch on is caffeine. So in terms of dosages for caffeine, we know that having at least one to three milligrams per kilo of body weight of caffeine has been shown to reduce rate of perceived effort and improve overall race times. So going slightly higher than this, so around that kind of three to six milligrams per kilo of caffeine, we know that this can improve times even a little bit more than the lower doses. And the mechanism here does seem to be involving the interactions with adenosine receptors and the nervous system to literally be able to improve performance and not just reducing perceived effort and kind of upping a bit of that cognitive function. So it could be worth doing for sure.

And then for long events, because caffeine does have a half life of about three hours, we would be looking potentially at utilizing caffeine throughout an event. So not just pre-event, but also during an event. And I find the best way to do this is to use caffeinated gels and things like that for a lot of endurance athletes. So you can use things like NoDoz, et cetera, but if you are wanting to hit on your carbs as well as your caffeine, I use logistically caffeinated gels with my Ironman athletes, et cetera, during long events and even longer training sessions. But it’s really individual because you do usually need to balance that with any gastrointestinal distress from taking on too much caffeine. So it’s usually also a in training thing that we would practice and then do on event day.

Aidan:

Another easy win is beetroot juice. So this is where we’re getting to the kind of hack portion of the thing. What else can we do that isn’t something that many people are doing? So beetroot juice is useful because it’s really high in nitrates. Technically a lot of vegetables contain nitrates, but beetroot specifically is higher than the other vegetables. As everyone knows when you juice stuff, it’s easy to consume large amounts. People worry about that with fruit and sugar because well, you’re going to be getting more sugar through juice because you’re able to consume the equivalent of more easily, but every nutrient increases. It’s the vitamins and minerals alongside that. Say a glass of orange juice is two, sometimes three oranges. It’s easier to drink that than it is to eat that, but the vitamin C is also in proportion to that. Same kind of concept with beetroot juice. It’s easier to drink it than it is to eat it, and it usually takes around 500 ml of beetroot juice to get to the clinical dosage, which I think from memory is the equivalent of almost a kilo of actual beetroot.

That’s a lot of beetroot. And what nitrates do is they help with vasodilation, which improves blood flow, which as you can imagine, carrying oxygen around the body can make it easier for endurance athletes. To make it even easier to consume than that 500 ml is to get concentrated beetroot juice shots. So Beet It is a company that does… I think their shots are 70 ml, something along those lines. So it’s really easy to consume. Doesn’t taste great. Not many people like it, but it is another option. Typically, it’s consumed one to three hours before the race because it has an acute effect. But research also shows that if you consume it for a few days leading up to race, it helps even more. It seems to be a cumulative effect up until about six days and then it kind of just plateaus and stays stable. So if you had it every single day, you won’t be getting any additional benefit, but there’d be no downside of doing that.

And another weird thing in the research is that elite level athletes seem to get less benefit out of beetroot juice than your, say, recreational athletes who aren’t as elite basically. But one of my speculations about that is maybe elite level athletes just have some of these adaptations already. Maybe their vasodilation is better. Maybe their blood flow is better. I don’t know. Their ability to carry oxygen around. I’m not 100% sure exactly why that happens, but that’s my speculation. But one way around this seems to be using an even higher dosage of beetroot juice. It seems like if you double the dosage, elite athletes are still getting benefit out of it. But one question I personally wonder is, I say 500 ml is the gold standard for the average person, do we know for sure that one liter wouldn’t be better? I don’t have an answer to that, but I’m like, if it’s better for elite level athletes, maybe it’s also better for recreational athletes and we’re just kind of underdosing it for the average person.

Leah:

Yeah. Awesome. I think it’s always fun to finish with a good hack at the end of an episode, but this has been episode 86 of the Ideal Nutrition Podcast. If you can leave a rating and review, that’s always greatly appreciated. But otherwise, thanks for tuning in.