Aidan:
Hello and welcome to the Ideal Nutrition Podcast. This is episode 103. My name is Aidan Muir and I’m here with my co-host Leah Higl. And today we are going to be talking about carb loading, which is not a topic I’m overly passionate about, but it is something that I think it’s worthwhile talking heaps about because it’s something that I think a lot of people, if they try to do themselves, they do not necessarily do a great job. Whereas if there is a structured plan and everything in place, it will significantly improve outcomes, which is why I want us to talk about it. So starting off with defining what a carb load is. A carb load involves an exceptionally high amount of carbohydrate consumption designed to maximise glycogen stores.
Leah:
Let’s talk about why you would actually carb load. That’s going to be a good place for us to start before we kind of get into everything else. But as you said, the basic premise of a carb load or carb loading is to maximise how much glycogen we have stored in our liver and our muscles. So what is glycogen? Glycogen is simply the storage form of carbohydrates, more specifically glucose that we have in our bodies that we can tap into. We also know that glucose or carbohydrates are our body’s preferred fuel source, particularly when we reach a certain intensity. So our body does use fats and carbohydrates and sometimes protein as a fuel source, but the higher the intensity of our activity, the more likely our body is to take from more so carbohydrates because it is a more efficient fuel source for our body to use.
So by maximising how much storage we have of glucose, we are able to maintain a higher intensity for longer basically. So that can lead to an overall improvement in performance in some activities. So using a bit of an example of I suppose what or how carb load could be beneficial is if we’re thinking about a longer marathon or marathon in general, and a lot of athletes find that they hit the wall, this is typically deemed to be when glycogen stores do get low and then performance falls off because our body then has to tap into more of our fat stores, which is a less efficient fuel source. So if we were to carb load and maximize those glycogen stores, we could then potentially start at a higher baseline of glycogen and therefore prolong the amount of time before we end up hitting a wall.
Aidan:
And a topic that I find super interesting is, I know pushing a threshold of what humans are capable of and we see that, say the two-hour marathon is a bit of a milestone, it has recently been broken. I don’t know if it was in competition, I think it was outside of competition, but technically that’s a barrier that humans have been like, “How do we beat the two-hour marathon?” And theoretically, if we push back that concept of hitting the wall by another five to 10 minutes, so many people are beating that two hour marathon mark. And it’s like, “How do we push that back?” There’s only really two ways. One is carb loading obviously, and the other is intra-race fueling like having heaps of carbs during the race. And right now, it seems like when people are optimising those things, this whole concept of hitting the wall seems to happen about an hour and a half in. It’s like, “Can we get better than that? I don’t know. Probably not.” But it means if you’re not doing those things, you’re selling yourself short basically.
So in terms of how to carb load, there have been quite a few proposed methods. One of the older school methods, which is a little bit more complex than what we’re going to talk about, involves doing high intensity exercise to deplete glycogen stores, which would then encourage glycogen super compensation. As you deplete, you have a bunch of carbs, your body’s trying to hold onto glycogen even more effectively. It takes you a little bit higher. It actually seems like we can get a tiny bit higher doing that than with other methods. But I don’t recommend that, I will kind of explain why. The current consensus is that carb loading is super simple and you just have one to two days of really high carbohydrate consumption, 10 to 12 grams per kilogram of carbohydrates is the number.
Just touching on why that’s potentially better than the other version, one simple reason is that the other version hasn’t been shown to outperform. It seems to take glycogen levels slightly higher. Let’s say you get to 100% with this 10 to 12 grams per kilogram and the other super compensation method gets you to 110%, it just seems like that additional 10% doesn’t actually do anything better. Some people made arguments that when people are so stocked up on glycogen that they burn through it really quickly at the start of races. I don’t know, it just seems like race times aren’t improving. And the other thing is the practical nature of it being like if you’ve just tapered for an event where it’s a marathon or whether it’s any other event, do you really want to be doing high intensity exercise one to two days out just to deplete glycogen?
Leah:
It doesn’t seem very effective.
Aidan:
It doesn’t seem very effective. So it’s like there’s so many angles you could look at that from, whereas it’s like, “Hey, let’s just have one to two days of really high carbohydrate intake.” Full context, a 70 kilogram athlete would require 700 to 840 grams of carbs to tick that box of 10 to 12 grams per kilogram. And if you don’t know what that looks like in food terms, it’s a lot.
Leah:
It’s a of carbs.
Aidan:
It’s a lot. And something that I don’t have research backing this up, but it was a statement I heard many years ago, and it lines up with what I’ve seen in practice is that when the average person tries to carb load, they usually have five to six grams per kilogram of carbohydrate. So when we are looking to get 10 to 12 to optimise things, that’s a very different number. And I can see how people fall so short because it’s a really high number.
Leah:
If you don’t know kind of what you’re aiming for and what that looks like, you’re definitely going to fall short because it seems like an absolute crazy amount of carb rich foods.
Aidan:
Yeah, exactly. It seems obscene, but it is what works best. And the final thing on that topic, kind of similar to what I was talking about exercise before, but it’s like another thing that you kind of need to do while carb loading is tapering your exercise or not really do anything during the time that you’re carb loading because you don’t want to be burning through that glycogen as you’re trying to store more glycogen as well. Although it would be very uncomfortable to be doing a lot of exercise while having that many carbs to eat.
Leah:
It is super uncomfortable. So let’s talk about who should and shouldn’t carb load because obviously it’s not necessary for everyone in every context, but a basic kind of rule of thumb would be anybody trying to maximise performance in infrequent endurance events that are over 90 minutes in length should do a full carb load. So the further you do get away from that description, the less likely you should do a carb load or a full carb load in general. So talking about slightly shorter events or the more frequently that you’re doing them that you could benefit maybe from a more scaled back version of a carb load, but maybe not a full carb load. And of course, if you are not trying to maximise performance, if that is not the goal, then a full carb load or a carb load in general may not be for you.
Aidan:
A few examples come to my mind. One of them is the maximising performance kind of concept. Shout out to our friend dietician Rose, but she put up a post on carb loading and somebody commented just being like, “You should specify that this isn’t for Sharon doing a marathon to lose weight.” Firstly, who’s doing a marathon to lose weight?
You’re not doing the event for weight loss. Secondly, clearly, this is just to maximise performance. Somebody who’s going to an event just because I want to finish, I want to tick off a goal or whatever, but they’re not trying to absolutely maximise performance. Does it matter if they get 10 to 12 or if they get five to six grams per kilogram? It just doesn’t matter.
Leah:
It really doesn’t matter. And I think something also to note is this is not something you do for training. It does go back to performance, but not performance in training, performance on an event day.
Aidan:
On an event, which then leads into that second point about the frequency. Say we’ve got an infrequent endurance event above 90 minutes. It’s like, “We should probably do a full carb load.” But say somebody plays soccer/football and they’re going for 90 minutes, but they’re doing it every week.
It’s like, do you carb load every single Friday 10 to 12 grams per kilogram, or do you do a scaled back one of six to eight or something like that? I think it makes sense to do six to eight, even if it’s just from that body composition perspective.
Leah:
Yeah, because you’d probably be over consuming calories potentially, or even just two days of not optimal protein intake, that’s a lot of… A high percentage of the week, you’d be then missing out on recovery. So it has to be balanced with other things.
Aidan:
And I’d still look at it being one day and so two days. But then it also means if you have a grand final, maybe you could send it.
Leah:
Yes, when it really matters.
Aidan:
Yeah, exactly. And some people would be like, “You don’t need a full carb load to optimize performance in soccer/football. We do have research showing that on average at halftime, most people are relatively depleted with glycogen, but that’s because they haven’t gone anywhere near a carb load leading up to it. So it’s like this actually does seem to matter and impact performance, but it’s just frequency. So the next thing, just going through some very quick tips as to how to get up to that high amount of carbs and make it easier to achieve this. So first one is using low fibre, easily digestible forms of carbohydrate. I wish I wrote some numbers down for some maths on this, but something that I think is interesting to think about is that two slices of wholemeal bread on average has about five grams of fibre and would be about 40 grams of carbs. Widespread would have the same amount of carbs, so same 40 grams, but it has about 1.5 grams of fibre for the two slices. I wish I wrote the numbers down to do the math on extrapolating that out over a larger amount. But it’s like if the average person is aiming for, say 30 grams of fibre, if you tried to get there with wholemeal bread, you would have an obscenely high fibre intake.
And what I think would be the ideal scenario is you keep your fibre intake relatively similar to what you normally do, which therefore necessitates you have to be choosing a lot of lower fibre foods so you don’t accidentally overshoot that.
The next one is to not go overly high protein or high fat while carb loading. And the simple reason for that is because your calorie content will get insanely high if you do have a lot of protein and fat. For context, 800 grams of carbs is 3,200 calories before factoring in protein or fats. If you limited protein or fats to a reasonably low level, maybe you could have a 4,000 calorie day, which for somebody who’s aiming for 800 grams of carbs, say carb load based on their body weight, that wouldn’t be obscenely high, it would just be a high calorie day.
If you proportionally increased your protein and fat alongside this, you’d be consuming well over 5,000 calories, probably 6,000.
Leah:
It’d be so much food.
Aidan:
It’s just too much. And that’s why people often fall short because… Using a bad example, but say you are like, “I want to have heaps of carbs, I’m going to have pizza for dinner.” That has a lot of protein and fat and it’ll be a lot of calories.
The next one is, don’t be afraid of higher sugar products because if you try carb loading with, say zero added sugar, it could be quite hard to achieve these numbers. I’m not saying make a large chunk of your carb intake coming from sugar, but say if you’re aiming for 800, you got five, let’s say 600 grams coming from not added sugar, you could quite easily add another 200 grams coming from sugar. Whereas if you tried to get that next 200 grams from non-sugar containing carbohydrates, it could be quite hard.
And the final thing is literally track your carb intake or make a plan. If you do not make a plan or have your carb intake tracked, you’ll probably get halfway through that number and be like, “I’ve had heaps of carbs,I’m done,” because it’s just hard to get to this number. And if you are listening to your body and trying to pay attention and everything like that, it’ll probably tell you to stop before you get to that number. So if you track, at least you know, “This is what I’m aiming for, this is how hard I need to push to kind of get to that number.”
Leah:
Adding a little more context to this, we’re going to go through what an 800 gram day of carbs would actually look like on a plate. This is adapted from our colleague Tyler’s blog post on the Ideal Nutrition website. So if you want to have a look at it, it is there. Look, this is probably not the best podcast content, but I think the context is definitely worth going through what this could look like.
So starting with breakfast, that could be six Weet-Bix, one and a half cups of skim milk, one banana and two tablespoons of honey. That’s 155 grams of carbs. Morning tea or snack one could look like 600ml of a full sugar Powerade, a chocolate chip muesli bar, and 100 grams of lollies. That’s 133 grams of carbs. Lunch could potentially look like a can of tuna, one cup of cooked white rice, 600ml of orange juice and 10 Jatz crackers. That’s 140 grams of carbs.
Snack two, five teaspoons of Milo, one cup of skim milk, four chicken avocado sushi rolls. That’s around 163 grams of carbs, and that’s quite a large snack.
That’s almost like lunch 2.0. Snack three, 100 grams of lollies again with another 600ml of Powerade. So that’s when the kind of added sugars come into it. Dinner could be around 200 grams of cooked pasta with some chicken, 600ml of soft drink and two slices of garlic bread. That’s 143 grams of carbs. And then finishing off with some dessert, a Magnum ice cream and another 40 spoons of Milo with one cup of skim milk, 60 grams of carbs. So that’s a lot of food in a day.
Aidan:
Yeah, it’s absurd. And one of the things in this adaption, we changed a little bit, but on the blog, you can kind of see that that snack three, the Powerade and the 100 grams of lollies, Tyler had kind of put that at the end being like, “And fit this in somewhere in your day.” I’m like, “I know what’s happened here”. He’s like written this out being like, “Let’s make an obscenely high amount of carbohydrates,” and then it came out as like 700.
Leah:
And it still fell short.
Aidan:
And he’s like, “I’ve got to add some extra. Where do I put it? I don’t want to add another meal, I’ll just put this at the end.”
Leah:
Yeah, 100%. So that is not something you would do, even if you’re like, “I’m just going to eat really high carb,” you’re not going to do anything close to that, likely.
Aidan:
Yeah, exactly. So some other quick notes. So one thing to touch on is water weight very briefly. So if you carb load, your body weight on the scale will likely go up one to two, maybe three, under extreme circumstances, kilos on the scale, right? It’s not really something to worry about. A lot of endurance athletes are conscious of, “If I’m lighter, maybe I will run quicker or whatever,” or maybe, “If I’m a cyclist going uphills, it’ll be easier and everything like that.” But the benefits of carb loading dramatically outweigh this. And the other thing is that it doesn’t matter from a body composition perspective or anything like that, somebody might do a day like this and be like, “I’ve gained three kilos very quickly,” but it’s not body fat or anything like that. It is largely watering collection and food weight.
On that topic with body composition, if done infrequently, this won’t matter. Let’s use marathons as an example. How often are people doing marathons? How many marathons are they doing each year? This isn’t going to affect your body composition. It’s just one or two days. It’s not a big deal.
Another quick thing is GI upset, gastrointestinal distress type situations. So doing some steps like going for lower fibre and everything like that should help with that. If you went for 100 grams of fibre versus say 30, you’re more likely to get some GI upset. But if you take the steps we kind of recommend in terms of not having an obscenely high amount of food in comparison to what you might need to get to this amount, and you still run into issues like say if you do everything right, maybe you could just scale it back to, instead of going 10 to 12, going for eight to 10, or maybe going for six to eight, scaling it back because pushing the threshold is always going to be better than what you would’ve done otherwise.
And the final thing to consider is, although I’m talking about it being like do this the day before or two days before, when you wake up for the event the next day, your glycogen stores have dropped a little bit overnight. So you will need a top-up in the morning, ideally just to get back to those peak glycogen stores.
Leah:
So ideally for carb loading, it is going to be for those people who are really trying to maximise performance in longer endurance events or events that are kind of stop start, but for that longer period of time. Ideally you will have a plan in place or you’ll be counting carbohydrates throughout the day because it’s very highly likely that without a plan, you’re not going to reach that 10 to 12 grams of carbs per kilo body weight for that one to two days prior. But it is very much well worth it for that uptake of maximising glycogen storage for particular events. So definitely something to be aware of if you are an endurance athlete or doing some events that are longer.
Aidan:
This has been episode 103 of the Ideal Nutrition Podcast. As always, if you haven’t left a rating and review, we would greatly appreciate that. But apart from that, thank you for listening.