Episode 480: Has Endurance Fueling Bonked?

For this episode, I dive into some of the extremes we often see with respect to fueling strategies in endurance sports, both on the high and low end of carbohydrate consumption, and what we can make of it all.

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Timestamps:

Episode Transcript:

[00:00:00] All right everyone. Welcome back. Today, I have got a solo topic based episode for you. The topic I'm gonna dive in today is gonna be on endurance fueling, and one of the reasons why I want to dive into this topic is because I've had some episodes recently where we've talked about this and you know, usually when I have a guest on the show, if we get into a topic, I try not to just go on a long rant or.

Just, uh, pour all the things I think about along the way. 'cause I want them to be able to say what they think and really give you their perspective to a large degree. So that kind of gives an opportunity for me to maybe leave some stuff out or not get as deep as maybe I could on something like a solo episode.

So I'm gonna do this one so that it can kind of pair with those previous episodes. If you're curious about me going a little bit deeper into some of my thoughts. Or as I continue to have conversations on this topic, on future episodes, you'll have an anchor point to reflect on. Or maybe you're just interested in this topic in general, my thoughts on it, in which case then this episode [00:01:00] will hopefully do that as well.

And another reason why I wanna do this is because I think with the way that this topic gets presented online and in general, in a lot of cases, we tend to look at it a little more black and white or either or. A lot of times since the extremes pull a lot more attention, we get to think those are kind of the options.

And right now within the sports, uh, or within the topic of endurance fueling, we kind of have both extremes. Raising attention at the moment, and this has actually been happening for a few years in some cases, but we've had some things that have been developing over a shorter period of time, yet even that have, uh, brought this topic back, back into the, the, the sphere of conversation.

So when I say the extremes with this, I'm referencing a couple things for the most part. One would be a recent analysis that came out from a group. Researchers that were looking [00:02:00] at low-carb ketogenic and their analysis essentially suggested that we may have been incorrect with our recommendations when it comes to endurance, fueling, and really the starting point should be simply 10 grams of carbohydrate per hour.

That's really extreme. On the low end, when we look at the recommendations as they currently stand, they are 30 to 90 plus grams of carbohydrate per hour, which. In and of itself is a very big range. So I think that's an interesting point just in general too, is I think sometimes people don't realize how big that range actually is from a recommendation standpoint and possibly why it's that wide.

So. If I unpack that a little bit, the reason it's that wide is because it's looking to inform a very diverse group of people from elite athletes that are operating on the very tip of the spear to people who are new to the sport or just much more casual about them. Training and development, in which case you're gonna have many different workloads per hour for those two populations, [00:03:00] and then everything in between.

And then you're also going to have a pretty diverse group of types of events. When we think about endurance sports in general, we're talking about Olympic distance stuff, all the way up to these multi ultra marathons essentially. So you have this. Massive range in duration and duration to a degree, is also gonna impact your fueling demands and what you'd likely want to be trying to target.

Again, another reason why we have a wide range within the recommendations. So a lot of times I think that just that tells people, okay, well kind of have me in a ballpark figure here, but what do I do within. And that's where I think you can, we can dig a little deeper to help people find that out. But when we talk about these extremes that fall even outside of those big ranges, that's where I think we even get a little bit more confused.

So if we look on the other side of this low-carb analysis, we have reports of athletes. And coaches just target what would likely go above the top end of that recommendation [00:04:00] where we see 150 plus grams of carbohydrate per hour. Now, technically 90 plus would include that, but I think when we start getting like quite a bit above that and we start seeing very, very small groups of people actually hitting that, then we are kind of getting to a similar extreme with respect to the 10 grams being on the outside of the other end.

So I think it is worth noting that. We do see a lot of conversation, a lot of anecdotes floating around about things that likely are probably pushing outward of the top end as well. And a lot of times the conversations kind of land into that, either or between those two and. And it's a pretty insane difference when you think about it.

Like think of 150 grams per hour versus 10 grams per hour. That's 15 times the difference. So that gives a lot of, uh, a lot of problems or situations to arise when people are trying to figure out what to do with that. So the way I like to start out with this is first, let's get to a point where we can eliminate as much bias as possible.

And the way I like to do this. Look at competitive pressure. In my opinion, competitive [00:05:00] pressure is the gold standard with respect to eliminating bias, because the bias there is actually just performance. It is trying to win. So when you have enough competitive pressure. In a sport, you really can't afford to have a bias that works against performance because if you do, you won't make it because the margins of error that will take you off a podium or take you outta the sport in some cases are razor thin.

So one benefit of looking at these highly pressurized competitive sports is we can even essentially cut through any of that potential bias. And when we do look at those sports, I think ones that make a lot of sense would be like the Olympics and. Endurance events like the marathon or big competitive marathons.

And like Tour de France cycling and things like that. Those are ones that have drawn tons of competitive pressure, have tons of money in it, and therefore are very highly incentivized to produce the best case possible inputs for [00:06:00] performance. And it allows us to, to take a peek into the impacts there because of that.

So the other thing I'll add with that too is a lot of times when you get. That's big. You have teams and doctors and groups of people that are working with these athletes and they're essentially running research that's unpublished with them that oftentimes will do things ahead of the science or ahead of the recommendations.

'cause they don't have to jump through those hoops. They just need to. Believe the system's gonna work to a high enough degree that it gets implemented, and then if it starts working and other competitors start adopting it, then we start seeing that kind of larger buy-in in it, and we see the direction of where things go a little bit more clearly by looking at that group sometimes ahead of time.

So I like to start there. And if we look at those groups of people within like competitive marathoning and Tour de France cycling and things like that, we see people pushing up to the high end or beyond the recommendations of that 30 to 90 plus grams of carbohydrates per [00:07:00] hour. And one of the reasons we see that is because these are gonna be individuals that have a very high amount of work.

Load per hour. So they would skew towards the high end of that in general compared to, you know, someone who's a middle of the pack or the back of the pack in these specific disciplines. So that is one reason why we kind of skew that direction, because they are likely going to be the higher fueling individuals to begin with, but we also see a lot of those individuals trying to push up high and beyond what we see.

Even the recommendations too. And in a lot of cases we see it working. So what that tells me is not that the average endurance athlete should say, oh, well, I guess since two De France athletes are hitting 150 plus grams of carbohydrates per hour, oftentimes, or because I read about an ultra runner who's hitting that high, or a marathoner who's hitting that high, I should do it too.

I think it just probably informs us that the intake of carbohydrates during endurance events does seem to have improved. To a certain degree, getting in more is likely going to create an advantage [00:08:00] of sorts within the specific context of the sports you're doing based on your workload and then the intensity and duration of the event itself.

So I think that ends up making it a good starting point for people to say, okay, well if my goal is performance and I don't have any reason to be picky, from a dietary standpoint, that's probably gonna gimme the best opportunity to. Perform at the best. If I'm working within that context of higher carbohydrates and consistent intra workout and intro race day fueling with carbohydrates.

Now I think there's probably some opportunity to pivot from that. 'Cause when we think about recommendations, a lot of times people tend to move away from the intent of that and think of them more as mandates of like, okay, you have to do this, or you're gonna fail. Or you can't do anything different and it won't work.

Recommendations are just starting points and there's gonna be individual variability. For me personally, like I don't think that there's, there is this no-go zone of low carbohydrate ketogenic [00:09:00] diet stuff within endurance sports. I think there are people who are going to respond better to that dietary strategy for whatever reason.

It could even just be simply, simply be that they adhere to it better and therefore enough things. That comes along with dietary adherence from a performance improvement standpoint, overshadowing any percentage performance loss they may take on by adopting that fueling strategy versus what we see people doing at the tip of the spear in sport.

And then there's also sports that we don't have a high degree of competitive pressure for yet, or not as high anyway. So if we get into ultra marathons or really long multi-day ultra marathons, we simply don't have the same amount of competitive pressure there as we do in some of these. Much more researched, much more delved into this type of sport.

So there is a little bit of learning still going on that is, that is gonna allow things that have been around for a while to still potentially stand out, that just haven't been tried yet at a high enough degree for us to know versus something like tour France athletes just [00:10:00] not knowing that a ketogenic diet would work better 'cause they haven't tried it yet.

Because they have, they've tried it, teams have tried it. It's been teased out. It's got filtered out from a performance standpoint because it just doesn't work to the same degree when you control for every variable and you optimize for performance. So. So there is that sort of range there. Alright, so now getting into some of the stuff and what we can learn and what we can do with some of these extremes and the information it provides us, we want to kind of get into some of the, the, the stuff that's being discussed around it or what we learned from it.

So the low-carb analysis that came out that suggested that 10 grams of carbohydrate per hour is going to do a good enough job at stabilizing blood sugar and blood sugar stabilization is essentially the. Major factor for performance optimization. It's suggesting that you don't need to introduce more than that because really all you gotta do is stabilize blood sugar and you can do that at 10 grams per hour.

That's kind of the short, quick summary of that. The reason why I think that's a bit of a stretch is, is. Not just [00:11:00] because we have tons and tons of evidence to point otherwise, where as you move up in carbohydrate consumption, during endurance sport, we see improved performance. But because of the way that this analysis and some of the studies that look at it.

Are done. They don't really compare it to what I would consider a very well structured, optimized, high carbohydrate approach. So we have this situation where we're kind of looking at, in my opinion, a ketogenic diet with 10 grams of carbohydrate per hour being compared to a. High carbohydrate diet that isn't being implemented optimally.

So if that's the case, then all we can really say from that is if you're on a low carb ketogenic diet and do 10 grams of carbohydrate per hour, you might get the same performance as you would if you do a high carbohydrate diet, but don't implement it properly, which if you're someone who says, well, if I do a high carbohydrate diet, there's no way I'm implementing it properly, then.

You know, maybe you find yourself in a situation where for you, at the individual level, [00:12:00] there is not a big difference there. But if someone is gonna sit down and say, okay, I'm gonna really look at how to implement a high carbohydrate diet, right? And then do the carbohydrate introduction at the right times during training sessions and races and, and not focus on the extremes, but.

Rather, what's gonna work for me with my context, I think that's gonna give them a little bit of an advantage in most cases, assuming they don't have other variables that impact how their body's responding to that approach that would otherwise be cleared up if they decided to abstain from carbohydrate.

Kind of back to what I was saying before with respect to the, some percentage of the population is just gonna prefer a low carb ketogenic diet better because they're gonna be able to adhere to it, and maybe that adherence in and of itself is. Gonna be something that helps them with improvement in performance that overshadows whatever potential deficit they would get by doing a different strategy.

One other thing I should mention too is outside of just what I talked about with respect to these studies [00:13:00] often don't inform us the same way that competition and competitive pressure does because they don't actually get. Slid into an actual protocol that would be used in route to the event is what are they actually looking at from a performance standpoint in the study of itself?

Because there's going to be a difference, in my opinion, on what sort of performance difference you see if you're testing someone. At an intensity that is, is, is changing throughout or at the higher end of the aerobic intensity spectrum versus something at the lower end. One thing that stood out was one of the performance comparators here was 70% of the O2 max.

That doesn't really inform me too much with anything new because. 70% VO O2 max is within the realm of possibility, in my opinion, that a low carbohydrate or even maybe a ketogenic diet isn't gonna produce like at least a major per like a big performance deficit because it's just not pushing up to where you actually [00:14:00] need that speed.

Of, uh, of fuel access, the way you'd get from a carbohydrate input. So I think it would be more interesting actually to run this where you had some sort of speed changes the way we would likely see occur during an event, or just focus more on the higher end of the aerobic intensity spectrum versus the lower end of the aerobic intensity spectrum.

The other thing that I think is really interesting when we look at some of this analysis is. I actually don't think it compares well enough to real world specifics, so I'll give you an example. I did a low carbohydrate diet for about 14 years to try to optimize a hundred mile ultra marathon, and in the early stages of that I played around with a strict ketogenic diet.

I eventually kinda moved from a strict ketogenic diet. Pretty quickly to a more low carbohydrate diet because I started noticing some suboptimal performance stuff that I thought would be, uh, a negative trade off on race day from a performance standpoint. And one of the things that I noticed was really interesting to me, one was if I went out and did like a [00:15:00] short interval session where I was targeting my velocity at VO two max while following a strict ketogenic diet, I didn't really have any noticeable performance dip during that one session.

But if I would take that session and then I would put it in the context of say, a three week training block that also had maybe another interval session later that week. Structured long run on the weekend and then rinsed and repeated for two or three weeks after that. That's where I started to notice my performance would dip during those interval sessions.

And then there would also be some days where I'd feel like a little flat on even a relatively lower intensity type training session. So. To me, what that said was, I might be able to do this once in a vacuum with this strategy, but that doesn't inform me on how it's gonna actually play out, when it's actually placed into a well-structured endurance training program.

And for me, what I did then was like, since I still wanted to try to leverage low carbohydrate for race day intensity, which for a hundred miles. Tends to be quite low compared to most endurance [00:16:00] sports. I'm operating right around my aerobic threshold versus, say like a marathon or a pro marathoner is gonna be operating really near their lactate threshold for race day.

You know, I wanted to try to maintain that without trying to compromise the non-specific intensities that still provide value for performance as best I could within the context of low carb. So I brought back some carbohydrates around those training sessions. Or higher than ketogenic to try to accommodate that and it, and that tended to work pretty well for me.

What you want to think about with that is like when you see these studies that show. Oh, we had them do this workout and then, when they were on a ketogenic diet, they didn't see any performance deficit compared to when they were on a high carbohydrate diet. That doesn't really tell me a whole lot about real world application because that was one workout.

So that could very easily be the same situation that I saw where I could go out and do that. Single workout at a high caliber relative to what I'd done in the past, and it was fine unless I continued it down the path, which you're going to have to do in order to prepare optimally for [00:17:00] a race. One of the other things that I noticed, and this kind of goes to what I was saying with respect to.

Comparing a ketogenic diet with 10 grams per hour to a sub optimally implemented higher carbohydrate approach was just some stuff that kind of popped up with that analysis. One was, which they were sending these high carb athletes into. A, uh, a performance task without actually targeting what would be considered probably an optimal amount of carbohydrate, both in the lead up to that activity as well as during it.

So there were situations where it was like long periods of time without carbohydrate prior to that activity, as well as, I wanna say, they had like 50 grams of carbohydrate per hour within the activity itself. So when we think of performance. We're probably pushing up inactivity when we're looking at performance higher than that in most cases.

Certainly if we're looking at anything that would resemble an elite or top performing performance. So I don't think it really informed us with [00:18:00] respect to what would happen if, say, we actually looked at the high carb research, which suggests when you go up in stages from 60 to 90 to 120 grams of carbohydrate, we see performance improvements.

All the way up to that 120 gram mark in some cases. So to me, it didn't really answer the question of optimal high carbohydrate performance versus optimal ketogenic endurance performance. With respect to that, it doesn't tell us anything. It tells us what, what it tells. What it tells me is that you can't make a performance claim with that analysis, and one of the problems I see isn't that the study was done.

I think there were actually a lot of good takeaways, which I'll get into from that study, in that analysis. But what happens a lot of times is when these things come out, it doesn't just kinda land in the science books and then all of a sudden, like people kind of digest it as they get to it. What happens is there's often a lot of talk about it, a lot of communication, a lot of promotion often from the people that are involved.

And one thing I saw with this particular analysis is when it came out, there was [00:19:00] a bunch of just really big claims that were made that were pointing towards no performance advantage to carbohydrates. So they were kind of setting the stage as, turns out you don't need to even engage with carbohydrates in any meaningful way in order to maintain your performance.

When in reality the analysis did not show us that. And the thing that's problematic with that is you'd get a big claim like that. Like I'll, I'll give you an example. There was a post that popped up. The myth of carb loading just got terminated. Another one was a new study. Eight weeks of high versus low carbohydrate diet patterns produced no difference in athletic performance.

So these are performance claims. These types of headlines, these types of posts, these are making performance claims. So once you do that, you are inevitably going to. Draw attention. And once you draw attention, what's gonna happen is people who actually know what they're talking about and have looked at this stuff and played around with this stuff, you search this stuff, they're gonna come in and they're gonna push back on that because to them that looks like a false claim.

That looks like you're claiming something that the body [00:20:00] of evidence that we have does not support. And what I often see with this is the person who knows, comes in and pushes back. And the person who made that. Kind of a big, grandiose claim about performance will then retreat back to something much more conservative, much more modest like, well, we're not talking about performance here.

We're talking about what the average person would benefit from. Well, now you just changed the topic. Now you just basically said, well, we're talking about something completely different here, even though. Your initial claim had performance literally right in it. So that's where I think it gets problematic is a lot of the communication thing.

So if you look back at some of the podcasts we've done, a lot of times when I've asked the guest about this, I'll say something like, I think the biggest problem with these sort of things is the communication side of it. Not that we can't pull something beneficial from that work that was done. And really that is the biggest issue I find.

So from that study, what did I find that was really interesting in my opinion, or helpful? Well, one is. We're actually starting to look [00:21:00] at performance optimization perhaps within the context of low carbohydrate ketogenic diets. So since I believe there is going to be some percentage of the population who wants to engage in endurance sports, who are gonna choose to follow a low carbohydrate ketogenic diet, it benefits us to know things about how.

Their performance is impacted and what protocols they should consider when they go into training and when they go into racing, since it likely will differ from what we would see from someone on a moderate to high carbohydrate diet. So this work does that for us to some degree, because historically there was this big question with if, well, if I'm following a ketogenic diet, what do I actually fuel with?

Do I not fuel at all on race day? Do I go back to high carbohydrates on race day? Do I take in fats on race day? Like what do I do? Well, at the very baseline of this, it suggests to us that there's actually a very large performance benefit for someone on a ketogenic or low carbohydrate diet to at least take in [00:22:00] 10 grams of carbohydrate per hour.

Now, these researchers didn't go beyond that. They didn't go and say, okay, well, 10. Grams in this case, I think they're time to failure tasks at, I believe 70% VO two max produce like a 22% improvement on time to failure or something like that. So that's a big difference. That shows like, hey, if you're on a ketogenic diet and you fuel with nothing versus 10 grams per hour, you're gonna see a noticeable benefit from that.

That's great information. That's great information for someone who's following an approach like that. That's great information for me as a coach, since I do have athletes that say, Hey, I wanna follow a low carbohydrate ketogenic diet. That's the way I'm gonna do it. And if there is a performance trade off here, I'm willing to accept that, but I do want to know what the best path forward is gonna be for me during a big workout or during an event or something like that.

This gives us a starting point. We can say, okay, well, we know at least 10 grams per hour is worth trying and seeing where we can go from there. So a little bit less guesswork. Now, what would be really cool is if this group would say, all right, let's. Let's further this research and now look at how does that 10 gram [00:23:00] per hour compare to 20 grams or 30 grams and do something similar to what the high carb group did, where they went from 60 to 90 to 120 to try to see if we see these low carb ketogenic endurance runners see additional benefits in performance.

If they say, do 20 grams per hour or 30 grams per hour, and eventually arrive at a framework that would be suggestive of. Performance within this context outside of just that one marker they looked at with 10 grams. So maybe we'll see that in the future. I think that would be pretty cool and it would just further inform us for those individuals who are interested in it and be able to help them out with what they wanna do for fueling.

When they, when they get their own race date. I think that's about all I got with this. I'm sure people will maybe have other questions, other thoughts and things about what they would like to know about. So feel free to shoot me a note if you do otherwise. Um, I think I kind of teased out a lot of, kind of what I've been thinking about with respect to this topic.

And hopefully I've given you some, some ideas to play around with, whether that be I'm on a low carb ketogenic diet. Where do my fueling ranges start? Or [00:24:00] I'm on a moderate high carbohydrate diet. Where do my fueling strategies fit within those recommendations? I'll, I'll just add to that, the 30 to 90 plus grams per hour.

One of the ways I really like to look at this is to start with workload. So think like. How much energy per hour am I going to be putting out in order to get to the finish line? And the higher that number is, the more carbohydrate per hour. The closer to the top end of that recommendation, you're likely gonna want to get.

And the lower that number is, maybe the lower you're gonna be able to sit because the workload is smaller per hour. Or another way I like to say this. So if someone was running a hundred miles and one person finished in 12 hours and another person finished in 24 hours, they might consume the same amount of carbohydrate during that hundred miles.

The one person may distribute it out over 24 hours, whereas the other has to pack it all into 12. So that's the way I like to look at this, at least a starting point. And then once you start kind of covering workload needs, then from there you can always. Play around with [00:25:00] more or less based on your own experiences because we do see hurdles that come up, whether that be like digestive issues by pushing too high or just people finding that they can benefit from going above their oxidation needs because there's other things that influence performance from carbohydrates outside of just defending car oxidation potentially.

So there it is. Let me know if you've got any questions. Until next time, it's the Human Performance Outliers podcast. Feel free to give it a share with your friends and followers. Help me grow the show.