Survive a marathon by eating the right carbs at the right time

By Catherine Orda | Photo by Justino Sanchez/Unsplash

A mistake no well-prepared athlete is bound to make a day or two before a race is to completely neglect carb-loading. It’s a pre-race strategy whose purpose is obvious enough: Carbs are a great source of energy, and if there’s one thing you need more than anything before a marathon, it’s energy.

And while that part of the strategy—knowing that you need to load up on carbs before race day—almost naturally occurs to most, many conscientious runners are still confused about certain things. For one, what specific foods should they eat? How much of these foods should they be eating? And the specifics don’t end there, as there’s also proper timing to consider. Proper carb-loading is an act that goes beyond mindlessly eating a huge bowl of pasta the night before a race—think of it as an extension of your pre-race training routine that requires the same kind of discipline and precision. With that, here’s everything you need to know about proper carb-loading:

Hitting the Wall

When you load up on bread or rice, the resulting carbohydrates are stored as glycogen in your muscles and liver. Glycogen is important in fueling your body during a marathon since it is what your body burns and converts into energy. But while it’s the most accessible energy source, it’s not the only one: When you run out of glycogen, when you hit “the wall,” your body will then resort to fat-burning—an inefficient process that slows your body down. So as much as possible, you want to load up on glycogen.

Benjamin Rapoport, a doctor and a marathoner, tells Runner’s World: “Proper carbo-loading—or filling your muscles to the brim with glycogen—won’t make you faster, but it will allow you to run your best, and, if you race smartly, avoid the wall,” he says.

What to Eat?

The one thing to consider when choosing which carbs to load up on is digestibility. You need not be restrictive on the kinds of bread or rice you’re going to be eating, as long as they’re easy to digest. Tortillas, oatmeal, bread, pancakes, waffles, peanut butter, sweet potatoes, pasta, bagels, yogurt, and juice are all great examples. It’s fruits that you have to be a bit wary of: While many of them are high in carbs, they’re also quite dense in fiber, which make them difficult to digest. This can lead to stomach trouble mid-race.

The process of proper carb-loading is a gradual one, and unless you want to run the risk of enduring stomach pains during a race, you shouldn’t cram two days’ worth of carbohydrates into a single, massive carbohydrate-dense meal hours before running

But if you can’t steer clear of fruits, then the best thing to do is to peel them in order to reduce their fiber content. There are low-fiber fruit options, too: “Bananas are a low-fiber choice,” says sports nutritionist Ilana Katz, who also encourages her clients to indulge in white bread and (peeled) baked potatoes.

Other things to avoid include high-fat foods and too much protein since both nutrients take long to digest. They also fill you up faster than carbs do. So if you’re loading up on white bread, make sure to replace butter with jam; if you’re planning to eat lots of pasta, avoid all cream-based sauces and opt for tomato-based ones.

On Proper Timing and Portions

When it comes to timing, the trick is to start incorporating carb-rich foods into your meals two or three days before a race. This window is the best instance to load up on carbohydrates and macronutrients. A carb-heavy meal the night before a marathon just isn’t enough to fill up your muscles with all the glycogen you’re going to need. The process of proper carb-loading is a gradual one, and unless you want to run the risk of enduring stomach pains during a race, you shouldn’t cram two days’ worth of carbohydrates into a single, massive carbohydrate-dense meal hours before running.

In fact, when you’re down to 18 hours before gunstart, it’s important to start reducing the size of your meals, as again, ease of digestion is something you need to watch out for. Two or three hours before the race, try to avoid all vegetables and fruits (except for bananas), fatty foods, and make sure to stock up on fluids as well.