What To Eat Before a Marathon To Optimize Performance, According to a Sports Dietitian

One rule of thumb: Don’t try anything new.

October 01, 2025

2236076078

Photo by: LUIS ROBAYO/Getty Images

LUIS ROBAYO/Getty Images

You’ve trained for weeks, battled weather, killer long runs, chafing and blisters. Hopefully you’ve also been stepping up fueling strategies along the way. Getting nutrition right for your needs as a runner is the key to unlocking your optimal potential.

Generally, you need plenty of calories from carbs, protein and healthy fats along with fluid and electrolytes. Including all these nutrients is non-negotiable. As race day approaches, play it safe. Limit or eliminate foods and beverages that tend to cause you digestive woes. Keep in mind that there’s no one size fits all for what to eat; it’s all a very personalized process. Focus on foods you like and tolerate well.

With that, here’s a breakdown of how to approach meals in the days leading up to a race.

1227543784

Photo by: photo_chaz/Getty Images

photo_chaz/Getty Images

What should you eat the week before a race?

As you taper your runs, increase your carb intake – this is the foundation of “carbo-loading” – which many runners get wrong. Take in extra liquids in small doses throughout the day to prevent bloating and plan according to the weather forecast. High humidity may call for extra fluid and electrolyte replenishment. Keep meals simple and balanced with protein, carbs and inflammation-fighting antioxidants from fruits and vegetables. Here are some ideas:

  • Smoothies made with fruit and yogurt or protein powder
  • Yogurt or cottage cheese bowls with fruit and granola
  • Turkey and cheese wrap with hummus and veggies
  • Pasta with salmon and salad
  • Quinoa with sweet potato and grilled chicken

2211321536

Photo by: Olga Mazyarkina/Getty Images

Olga Mazyarkina/Getty Images

What should you eat the night before a race?

Marathon eve is for your favorite go-to dinner. You want a meal that you love the taste of and digest comfortably. Be generous with the servings of carbs, choose lean protein and keep it light on fiber. Opt for cooked vegetables over raw for easier digestion and give yourself plenty of time to digest the meal before heading off to bed. If you have traveled out town for the race and need to rely on take-out – plan ahead or don’t be shy about asking a restaurant to modify the meal to your specifications. Opt for meals that look like:

  • Pasta with chicken and cooked vegetables
  • Tofu stir-fry noodle bowls
  • Steak, rice and roasted vegetables
  • Ground turkey with rice and steamed carrots

1049168252

Photo by: Arx0nt/Getty Images

Arx0nt/Getty Images

What should you eat on race day?

Most marathons begin in the morning, so a properly balanced breakfast is imperative. The time you need to get up will dictate what you have time to eat and digest comfortably.

The number one key to success on race day is stick to what you know. Resist the temptation to experiment with giveaway items out on the course – you don’t want to learn they don’t agree with you while you are running the race.

By this point, you probably know the snacks and electrolytes that work for you during a run. Stick to your plan and you will do great.

A balanced race day breakfast might look like:

  • Bagel with peanut butter and banana
  • Overnight oats with granola
  • Toast with scrambled eggs and applesauce
  • Breakfast burrito with eggs, cheese and potatoes

Related Content:

Next Up

8 Store-Bought Snacks That Are Good To Eat During a Workout, According to a Sports Dietitian

Snacking needs during long or strenuous workouts are different than any other time you snack. Here’s what to look for to optimize your performance.

The Best Post-Workout Snacks You Can Buy, According to a Sports Dietitian

Refueling properly is essential for recovery. Here’s what to look for.

The Healthiest Boxed Pastas, According to Dietitians

How healthy a bowl of pasta is comes down to what you serve it with, but it’s still worth starting with a nutritious base.

What You Should Eat Before and After HIIT Workouts, According to a Certified Athletic Trainer

Here are best practices for properly fueling and recovering from high-intensity interval training.

The Best Whole-Grain Breads, According to Dietitians

Get your daily dose of whole grains without skimping on flavor.

The Best Lower-Sugar Cereals, According to Dietitians

Here's what you should check for when choosing a healthier breakfast option.

How to Pick the Best Sports Drink, According to a Certified Athletic Trainer

Picking the right drink for your fitness needs can impact your overall performance. Here's how to choose.

The Best Low-Sugar Breakfast, According to a Dietitian

No need for the morning rush to be a sugar rush, too.

The Best Diabetes-Friendly Cereals, According to a Dietitian

Here are the three things you should look for when going through options.