How Many Gels Do You Need for a Marathon?

In addition to many miles of buildup, interval workouts, and strength training, running a marathon also calls for a solid nutrition plan. Rich in carbohydrates and electrolytes, energy gels are an easy way to digest the fuel needed to support your body for the demands of 26.2.

Made to fit in a portable, handheld packet, energy gels are an easy way to consume carbs while running. Roxanne Vogel, Nutrition and Performance Research Manager at GU Energy Labs, says current research suggests we need about 30 to 60 grams of carbohydrates per hour of exercise while working out at a moderate intensity level, like running a half marathon or marathon. The amount can be slightly higher, about 60-90 carbs per hour, if you’re doing an ultra distance.

If you divide that amount by the number of carbohydrates in your gel (most contain about 20 to 25 grams depending on the flavor), you’ll need two to three gels per hour during a half marathon and marathon, depending on how long it takes you to finish.

While each brand of energy gel has its own recipe and benefits (be sure to test different options to determine what works best for you ahead of race day), this is a general range that’s recommended for the marathon distance.

We have carbohydrates stored in our body, but there’s a limited supply—about 500 grams or 2,000 calories worth of carbohydrates, to be exact, according to Vogel. When you’re running at a moderate to intense effort, most people go through that amount and hit glycogen level depletion—when your body starts to run out of energy, also known as bonking in a race—in about two to three hours. “To avoid hitting the wall, you need to replenish those carbohydrate stores while you’re exercising, so you don’t get to that depleted level,” Vogel says.

The longer you exert yourself, say in an ultra marathon, the more calories you burn over a prolonged period of time. To avoid the deficit, it’s important to consume as many calories as possible without overloading your system, Vogel says. “You want to give [your body] enough to replenish what calories you’re burning during exercise, but just enough to stave off that total depletion,” she says. “The longer you’re going, the more calories you’re burning, the more aggressively you need to try and match that calorie expenditure.”

When consuming energy gels during a race, be sure to hydrate properly to allow for easier absorption along the way.