Carbohydrates and Runners: Friends or Foes? A Dietitian’s Perspective

Carbohydrates for runners have been misunderstood for years, especially with the rise of low-carb diets like keto, Atkins, and paleo. But for endurance athletes, cutting carbs may actually hurt performance rather than help it.

What Are Carbohydrates, Really?

So what exactly is a carbohydrate? Carbohydrates are sugars, starches, and fibers. They are found in foods such as breads, pastas, rice, grains, cereal, fruit, vegetables, sweets, sports drinks, and so much more! All different types of carbohydrates play an important role in a runner’s diet.

Carbohydrates are our body and brain’s main source of “fuel” or energy. Without enough carbohydrates (energy) in our diet, we can experience difficulty concentrating, brain fog, fatigue, headaches, and irritability. For runners, carbohydrates are especially important since they are the preferred fuel source for endurance activities.

How Carbohydrates Fuel Your Run

When we consume carbohydrates—like a bowl of pasta the night before a long run—they’re broken down into simple sugars that can be used right away or stored for later. Stored carbohydrates are primarily found in your muscles and liver. During long-distance running, we often rely on these stored carbohydrates for energy—thanks, pasta! If these stores are depleted, that’s when runners often “hit the wall.”

To avoid hitting the wall, it’s essential to consume adequate carbohydrates before, during, and after training.

Before the Run

Before a run, the focus should be on simple carbohydrates because they break down quickly and provide immediate energy. Simple carbohydrates include white bread, bagels, fruit, honey, and syrup. The amount needed will vary depending on the person and the duration of the run, so it’s best to reach out to a dietitian for a more in-depth analysis of your individual needs.

During the Run

Carbohydrates are also important during a run, especially if you’re running for longer than 70 minutes. This helps prevent your energy stores from running out, which in turn helps prevent the dreaded “wall.” Again, simple carbs are best—think sports drinks, gels, chews, honey, syrup, applesauce, or even gummy candy! Keep in mind that consuming carbs mid-run takes practice, so give yourself time to see what works best for your body.

After the Run

Once you’re done running, your body needs to replenish its energy stores with carbohydrates. That’s why your post-run nutrition should contain a significant amount of them. Great sources include chocolate milk, bagels, potatoes, pasta, and rice.

Personal Needs Vary

The exact amount of carbohydrates you need depends on factors like body composition, activity level, and more. To make sure you’re meeting your needs and supporting your running goals, it’s smart to meet with a Kansas City-based dietitian for personalized guidance.

Need help fueling before your next long run? Check out our favorite on-the-run nutrition options available at The Running Well Store.

About the Author

Cameron Mottet is a registered dietitian, owner of Thrive Nutrition Kansas City, and is licensed in Missouri, Kansas, and New York. Cameron earned her bachelor’s degree in Human Environmental Science, majoring in Human Nutrition and Hospitality Innovation with an emphasis in Dietetics from the University of Arkansas in 2019. During this time, she interned for the KC Royals minor league baseball team.

She then received her master’s degree in Medical Dietetics and completed her dietetic internship at Saint Louis University in 2020. After passing her Registered Dietitian Exam that same year, she began helping individuals achieve new health goals related to performance nutrition and weight management.

Cameron has been practicing dietetics for nearly four years, with her main expertise in weight management. She is now a Board Certified Specialist in Obesity & Weight Management (CSOWM).

Although weight management is her main area of focus, performance nutrition is her passion. As an avid runner who has completed 13 half marathons and one full marathon, Cameron enjoys working with runners and athletes to improve their nutrition and reach their goals. Outside of work, she spends her free time lifting weights, country swing dancing, cooking and baking, and traveling!