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What to Eat Before a Marathon

Posted May 02, 2023 by Michelle Boltz, MS, RD, CSSD, LD

Workout

Pre-race dos and don’ts:

You’ve trained hard! You’ve consistently fueled your body throughout the training process, and you are now ready to run 26.2 miles! But what should you eat before your race begins?

Below are some race-day fueling tips to have you feeling, and performing, your best! Finish strong by following these tips according to the Academy of Nutrition and Dietetics, Dietitians of Canada, and ACSM.

Do: eat early.

In order to “top off” your gas tank, you’ll need those carbohydrates to provide glycogen to your muscles at the right time. It takes a few hours for food to digest, so if your race time is 7:00 am, you may need to set an alarm for 4:00 am in order to eat, and then you can go back to bed.

Do: eat carbohydrate-rich foods.

Carbs provide energy and fuel the muscles! Protein and fat may be tolerated 3-4 hours before race time. As race time gets closer, limit protein and fat.
Examples for fueling early may include:

Bagel or toast (carb) with peanut butter (protein/healthy fat)
Yogurt (carb + protein)
Hot or cold cereal (carb)
Fruit (carb)

Do: avoid protein and fat 1-2 hours before race start time.

As noted above, protein, and a little healthy fat, may be tolerated 3-4 hours before race time. However, because these nutrients take longer to digest, eating too close to race time could slow you down and cause gastrointestinal discomfort.

Do: drink before you race.

You want to start exercise in a euhydrated state. To know if you are euhydrated, check your urine color to see that it is pale yellow. Drink 5-10 mL/kg (~ 2-4 mL/lb.) of water or sports drink, 2-4 hours before race time, and then ~ 1 cup, 10-20 minutes before the race.

Don’t: eat or drink anything that you have not tried during training.

Remember, you have to train your gut, just like you train your muscles. You won’t know if a new food or beverage agrees with you if you haven’t already tried it. To help avoid digestive issues, stick with the foods you have consumed along your training journey.

Don’t: eat high simple sugar and high fat foods.

Foods that contain high fat and simple sugar, such as doughnuts or pastries, may cause an upset stomach and diarrhea. Plus, the energy these foods provide is not long lasting. There are many miles ahead, you need foods that will fuel your body all the way to the finish line.

Don’t: eat high fiber foods too close to race time.

High fiber foods may cause gastrointestinal discomfort. During your race, you want to be focused on the next step, not an upset stomach.

Nutrition is a crucial piece of marathon training. As your next race nears, be sure to keep this list of pre-race nutrition tips handy.

Learn what to eat during a marathon.