Why Runners Need Carbs

Carbs for runners - spaghetti

You are a runner. You’re lacing up your new neon shoes, pounding the pavement and breezing past pedestrians. Sweat bands, water bottle, playlist, keys—you have all the essentials. But did you remember to get your carbs in today?

Yes, they’ve gotten a lot of flack lately, but carbohydrates can be the most important nutrient on tough training days so it’s time to give those carbs the love they deserve! Here’s the low-down on how your body fuels up and uses carbohydrates for energy.

Carbs propel you to the finish line!

Carbohydrates, specifically glucose, keep you going during a run. Glucose is converted into energy that contracts exercising muscles—the faster and longer you run the more glucose you use up! Key things to know about glucose:

  • Glucose is needed for you to optimally burn fat during your run. During long runs, fat is the other important nutrient that turns to fuel, but your body can’t properly use fat without glucose present.
  • Glucose is the number one fuel for your brain almost all of the time. The brain detects when glucose levels in the blood drop, and you experience it as confusion, disorientation, and fatigue—hello, bonking! Having enough glucose on board can prevent the dreaded “wall.”
  • You have a limitless capacity to store fat, but not glucose. Your body stores glucose in the liver and in your muscles in the form of glycogen. And your body can only store enough glycogen for about 90 minutes of strenuous exercise—which explains why many runners choose to “carb load” before a race.
There’s a right way to “carb load”.

Eating high carb foods leading up to a race, or “carb loading,” stocks your muscles and liver with glycogen. But it’s only necessary if you’re exercising intensely and continuously for 90 minutes or more. (If you did it before every run, you’d likely notice your shorts getting snug.) To get the most bang from your carb-loading buck:

  • Ramp up your carbohydrate intake 1 to 3 days before a long run with a high carbohydrate diet. Average runners should aim for 5 to 7 grams of carbohydrates per kilogram of body weight, and endurance athletes should aim for up to 10 grams of carbohydrates per kilogram of body weight.
  • 3 to 4 hours before exercising, eat a high-carbohydrate, low-fat meal, such as a turkey sandwich with lettuce and tomato, or pasta with chicken and veggies.
  • Right before the race, opt for simple carbs that are easy to digest—things like white rice, pasta, pancakes, cereal, fruit bars, and baked goods—to avoid stomach trouble on the road.
Carbs play a big role during and after, too.

Taking in carbs during a run slows down the rate at which you use your stored glycogen, and helps keep you going for longer—which explains why you’ll find sports drinks and gels at aid stations for long races. And when you consume carbs and protein post-exercise, you set your body up to optimally restock glycogen stores for the next run and help rebuild muscles. A few things to keep in mind when fueling on the run and after:

  • 30 minutes before exercising, have a simple carbohydrate snack, like a piece of fruit, applesauce, a handful of dried fruit, or crackers.
  • During physical exertion, aim to sip 8 ounces of sports drinks every 30 minutes, or consume  1 to 2 sports gel packets with water every 45 to 60 minutes.
  • Within 30 to 60 minutes after exercising, have a snack or meal that combines carbohydrates and protein. Some good options: a peanut butter sandwich, chocolate milk, a banana with a serving of almonds.

Want some more meal inspiration? Check out some healthy recipes from MyFitnessPal:

Protein Packed Pancakes
Banana Bread Overnight Oats

Turkey Apple & Chutney Sandwiches
Fruit + Almond Butter Quesadilla

Asparagus Pasta Pea Bowl
Roasted Butternut Squash Pappardelle

By Trinh Le, MPH, RD


100 million members strong, the MyFitnessPal community is the largest worldwide audience in the health and fitness vertical. Our precise, personalized and powerful tools make it easier for anyone to live a healthier life by tracking their nutrition and physical activity.

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