How to Eat For a Marathon

When prepping for a marathon, most of us think of one word: Training. But there’s another word that’s just as important: Diet.

Most athletes try to be cognizant of what they put in their bodies. However, eating well versus eating to compete are two separate things.

To get a better understanding of what it takes to fuel for such an athletic event, I reached out to Lisa Dorfman, MS, RD, CSSD, LMHC, and FDND. Globally known as The Running Nutritionist® and the author of 8 books, she’s competed in more than thirty-four marathons herself.

“I believe that whether it’s the beginner or the gold medalist, nutrition is 99 percent of it,” she says. “Where most athletes go wrong is that they don’t change their training diet to a competitive diet…You have to fuel differently to get where you want.”

The Training Diet

When building a training diet, a runner needs to consider personal calorie needs, as well as the speed and intensity they run at. “It’s all about keeping you well,” Lisa explains. “It means getting enough variety in your diet that you’re meeting your protein needs, your carbohydrate needs, your healthy fat needs, your vitamins, your minerals, your fibers.”

Depending on where you are as a competitor, you will be training for a minimum of 12 weeks. As you move from your base mileage to longer distances, your food intake should increase to meet the new physical demands.

This is not a license to go crazy during meal times. It’s important to make sure you’re consuming the right ratio of complex carbohydrates for energy, high quality protein and fats. Lisa recommends that runners visit a sports nutritionist before beginning a new running program, so they can evaluate where they are nutritionally. From there they can chart how calories and macros will be adjusted for each phase of training. As they become acclimated to their new program, they can start testing when and how much they need to hydrate during runs.

Transitioning to a Competitive Diet

Three to four days from a marathon is when the shift from a training diet to a competitive diet should take place. From here, the focus is not only about getting enough energy but creating what Lisa refers to as “a quiet belly.” The last thing you want is a stomach on the fritz.

The idea is to slowly taper off from foods that could upset digestion, leading to an interrupted run come race time. Fibrous foods should be avoided, along with excess oils, anything fried or spicy. Carbohydrates should increase but, as Lisa explains, come from simple sources like white rice or substituting fresh fruit for smoothies.

“You want to take whatever carbohydrate level you are starting on and pump it up,” she says. “It’s like you’re packing for vacation. You want to pack your muscles with enough glycogen that will last you a pretty good time on the road.”

Your protein intake is not as crucial leading to competition and can be decreased, provided you’re getting enough to facilitate muscle recovery. It should also be spread throughout the day and from high quality sources. “Maybe an egg in the morning, a sports shake or smoothie,” Lisa suggests. “Maybe In in the afternoon an endurance drink that has a few grams.”

Competition morning, runners should eat a plain breakfast (think dry cereal or toast) and have their coffee 2-3 hours prior. This gives the body enough time to digest and evacuate itself.   “You’re not dependent on that meal to run the best marathon,” Lisa says. “[It] depends on what you’ve been eating the three or four days leading up to it and the change over from the training diet.”