Macro Splits For Runners

Hi folks, this is a follow-up to the last video I did on nutrition, where we talked about caloric intake and the value of  checking in periodically to make sure that we’re actually getting enough food, because it’s not uncommon for runners to underfuel. Calories are obviously only part of the picture, though. What those calories are, in terms of macronutrients, is also really important.

The Role of Macronutrients in a Runner’s Diet

When we talk about macronutrients, we’re talking about carbohydrate, protein, and fat. In this video, we are focusing more towards the end of performance because, in terms of diets, low carbohydrate, high fat diets work generally, and high carbohydrate, low fat diets work generally. There are definitely populations within that that should maybe gravitate towards one rather than the other, and that would be more towards a higher carbohydrate diet, particularly if you’re exercising.

But what we’ve got to be quite careful of sometimes is that we don’t gravitate into the sort of moderate carbohydrate, moderate fat intake because that can leave us feeling sluggish in our training. And also it can drive weight gain.

Caloric Distribution and Macronutrient Ratios for Runners

The numbers I’m going to discuss now should be taken as rough guides, but it is worth checking in periodically to see where we land with our macro splits. In terms of where your calories are likely to come from as a runner, we are generally looking for about 50% from carbohydrates, 25% from protein, and 25% from fat. All of these macronutrients are super important, and depending on a runner’s goals, the ideal macronutrient split might look quite different.

For example, we might be slightly higher in protein if we strength train as well, and we might be slightly higher in protein, maybe for an older athlete, where protein synthesis becomes more difficult as we age, and so we might just need a little bit more of it.

The Importance of Carbohydrates in Endurance Sports

So, let’s focus on the carbohydrates for a moment. Carbohydrates are essentially a type of sugar, and we store sugar within our muscles and use it when we train. That’s why we need to eat when we run on longer runs. That’s why people talk about “hitting the wall” in events like the marathon where we’ve actually depleted our muscle glycogen.

In simple terms, carbohydrates end up in the muscle in the form of muscle glycogen. We can think of muscle glycogen as like a cup within the muscle with the fuel, muscle glycogen in there and the cup continuously leaks. It’s got little holes in it and it’s continuously leaking because we continuously use muscle glycogen. And then every now and then when we eat carbohydrates, we put a little bit more in to top the cup up. But when we do exercise, we tip quite a lot of this muscle glycogen out.

We therefore have to make sure that, over long periods of time, we’re not chronically depleting our muscle glycogen stores. So in other words, the amount we top it up isn’t as much as the amount that we’re using and eventually it just ends up settling quite low and that’s when we can feel quite lethargic on runs. That’s why we need to make sure that, particularly a few days before a longer run, we add a little bit more extra starchy carbohydrates, we have a carby breakfast, we eat carbohydrates on the run. And then after our longer run, we refuel really soon to make sure that those muscle glycogen stores are topped back up.

So it is worth checking in every now and then on your caloric intake to make sure that you’re somewhere near, and your macro split to make sure that you’re somewhere near, bearing in mind it will be different for different individuals. But the sort of area that we’re trying to avoid is that moderate carbohydrate, moderate fat, quite low protein. That’s not really helpful in terms of training and can drive weight gain.

So the recommendation for endurance sports is a higher carbohydrate diet just to make sure that our muscle glycogen stores are topped up, which will lead to good sports performance. If you have any questions, please just get in touch. And for now, Happy Running!