What to Eat Before a Half Marathon

Your diet before a race can make all the difference

If you’ve signed up for a half marathon, you’re about to take on perhaps one of the most difficult and rewarding physical challenges you’ve ever faced.

First and foremost, start with a proper training plan. Following an established plan that enables you to build up to 13.1 miles over time will help you get closer to your goal.

But exercise is only part of the equation. What you do in the kitchen is another part. Like fuel in a car, your diet influences your body’s performance. Quality fuel can lead to better training, which leads to better performance on race day.

“When you’re running a half marathon, you could be out there for more than 2 hours,” says Mohamed Shitia, DO, a sports medicine specialist at Geisinger. “You can’t run on empty — you need to make sure you properly fuel your body not only ahead of time, but also during and after every run. This means following a diet designed to help you perform your best.”

Failing to prepare nutritionally might be the difference between smashing a personal best and hitting a wall a few miles before the finish line.

Here’s a guide to fueling for your first — or 5th — half marathon.

Diet for half-marathon training

About 3 months before, take some time to map out your workouts and dietary changes from now until race day to fuel progressively longer runs.

A proper balance of macronutrients can enhance your endurance training and fuel your body for energy, repair and recovery — and ultimately help you reach your race-day goals.

Carbohydrates are the primary energy source for long-distance runners. Consuming an adequate amount of carbohydrates in the days leading up to your race guarantees that your glycogen stores are fully stocked to provide essential fuel for your muscles.
Proteins, while not the main energy source during a race, are the building blocks for muscle repair, growth and recovery. Muscle recovery can impact your performance in subsequent workouts.
Healthy fats provide a secondary energy source during longer runs. Healthy fats, such as those found in avocados, nuts and olive oil, help sustain energy levels and support long-term endurance.

While you do need more calories when you’re training for a half marathon, you don’t need to go crazy. Generally, you should add an extra 200 to 300 calories per hour that you work out.

“Make sure you’re consuming enough calories throughout the day and meeting your nutritional needs with essential vitamins and minerals,” says Dr. Shitia. “If you’re following a fad diet, consider switching to a balanced, sustainable eating plan that includes lean protein, whole grains and plenty of fruits and vegetables.”

The importance of carb loading

About a month from race day, you may be running anywhere from 15 to 25 miles per week. It’s vital to make sure you’re focusing on complex carbohydrates to maximize glycogen stores in your muscles and liver — the fuel source your muscles rely on during long-distance events like half-marathons — to improve endurance and reduce fatigue.

“Complex carbohydrates are the best source of energy for a workout because they offer sustained energy rather than a quick burst of energy followed by a crash,” explains Dr. Shitia. “They are foods that are slowly converted into sugar in the body. Pasta, whole grains, beans, lentils, potatoes and squash are all examples of complex carbohydrates.”

Try to eat complex carbs at least 2 hours before a workout. After working out, eat a meal with complex carbs and a serving of protein to help rebuild your muscles.

Several weeks before the race it’s also important to create your pre-run fuel routine. Now’s the time to figure out whether whole grain toast with nut butter agrees with your stomach, for example.

Meal planning a week before the race

About a week before the race, you should begin eating more complex carbs than you were previously. This means eating meals like oatmeal for breakfast, rice- or potato-based dishes for lunch and pasta for dinner.

You can start sacrificing otherwise-healthy foods in favor of complex carbs. Opt for easily digestible foods and start tapering off your leafy green vegetable intake, as they can be hard on your stomach during a run.

Aim to eat about 3 to 5 grams of carbohydrates per pound of body weight daily. For example, a 150-pound person should aim to eat about 450 to 750 grams of carbohydrates each day. And pair your carbs with lean proteins like chicken, turkey, fish or plant-based options (beans and lentils) to support muscle recovery.

“You may notice that you’ve gained some weight, but don’t worry — this is completely normal,” says Dr. Shitia. “It means your body is storing carbohydrate energy, known as glycogen, in your liver and muscles. During the race, your body will tap into this stored energy to help you power through and finish strong.”

In the days leading up to the race, make sure to prioritize hydration as well. Drink plenty of water and consider incorporating electrolyte-rich beverages to help maintain energy and improve overall performance.

What to eat the night before a half marathon

What you eat the night before a half marathon can significantly impact your performance. Aim for a carbohydrate-rich meal with moderate protein and healthy fats. But, take it easy.

While many people are tempted to eat a big meal the night before the race, this isn’t a good strategy. Overeating can cause stomach pains and slow you down during the race. Instead, opt for healthy small meals like cheese and crackers, half a sandwich or whole-wheat toast with avocado and egg.

Once you reach 18 hours before the race, start to decrease the size of your meals. Lunch the day before the race should be your last normal-sized meal. This allows your body enough time to digest and store glycogen.

What to eat on the morning of a half marathon

On race day, practice your pre-run fuel routine by eating a small meal of carbs, like a banana with oatmeal or a bagel. Now is not the time to experiment with an unfamiliar food — or high-fiber foods and proteins like eggs that take a long time to digest.

Ideally, you should eat 2 to 3 hours before the race starts to give your body ample time to digest the food and convert it into usable energy. But because most races start early in the morning, consider a light snack for breakfast about an hour before start time.

During the race, focus on staying hydrated and balancing your carbohydrate and electrolyte needs. Drink water along the race route at about the same rate you did during training and try to avoid drinking too much. In addition, small, simple carbohydrates like gels can help you maintain the energy you need to finish strong.

Importance of post-race nutrition

You crossed the finish line! You’re done, right? Not so fast. Now it’s time to refuel for recovery. Your body has just endured significant physical exertion — and is nearly depleted of carbohydrates. Post-race nutrition is key for replenishing glycogen stores, repairing damaged muscles and restoring hydration.

Focus on a combination of carbohydrates and protein to effectively kickstart the recovery process. A whole grain sandwich with lean protein, banana with nut butter and trail mix are excellent choices. A smoothie made with Greek yogurt, fruit and spinach also can serve as a delicious recovery choice, offering both hydration and nutrients.

“Continue to carb load about 24 hours after the race to restore your body’s glycogen levels and after that you can return to your normal diet of protein, healthy fats and fiber,” says Dr. Shitia. “With proper nutrition, you’ll recover faster and soon feel ready to take on your next running challenge.”