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Why Carbs Can Help You Crush Your Next Run Performance

MAR. 17, 2023
As runners, we’re always looking for tips and tricks to improve our performance.
Weekly Meal Prep Low Calorie

You’ve likely heard about the importance of eating carbohydrates before a race, but do you understand how and why?

Carbohydrates provide fuel for your body, supporting your ability to go longer and faster. Carbohydrates are often referred to as “The master fuel.” And for good reason. Researchers found that eating carbohydrates improved endurance as early as the 1930s. Studies show that consuming increased carbs during training and endurance exercise can support better performance while delaying the onset of fatigue.

Ready to crush your next run? Here’s a more detailed look at why carbs can help you meet your goals, information about different carb types, and some suggestions for ways you can work it into your routine.

The Link Between Carbs and Endurance

Think of carbs as fuel. They’re your body’s main energy source. As your body breaks them down during the digestion process, it turns those carbs into sugar that enters your bloodstream and provides energy to your cells. That sugar gets stored as glycogen in your muscles and your liver.

Normally, your muscles only store enough glycogen to support your body during everyday activities and recreational exercise. But if you're an endurance exerciser — someone who exercises for 90 minutes or longer — your muscles could run out of the glycogen you've stored. That's when performance falters and fatigue sets in.

Enter carbohydrate loading. This is something that you'll do about a week before a race or a high-endurance activity. The purpose is to increase the amount of carbs you're eating to store more energy for increased stamina.

Two people running

Simple Vs. Complex Carbs

Not all carbs are equal when it comes to nourishing your body and supporting it during strenuous activities like training and races. There are two basic types of carbs: Simple and complex. Simple carbs are those that your body digests quickly. They contain minimal nutrients and fiber, which is why these carbs have a great impact on blood sugar levels. You'll find these carbs in sugary drinks, desserts, and refined grains like white bread.

Your body digests complex carbs slowly. These carbs contain more fiber and more nutrients to nourish your body. Examples of complex carbs include whole grains, vegetables, whole fruits, nuts, beans, and seeds.

To give yourself maximum energy for running, experts recommend getting your carbs from a variety of sources. Examples include:

  • Starchy vegetables like squash, peas, and sweet potatoes
  • Whole grains and gluten-free grains like quinoa and buckwheat
  • Bread, cereal, crackers, and pasta
  • Whole fruits like bananas, apples, and berries
  • Legumes like chickpeas and black beans
  • Milk
  • Yogurt

How Many Carbs Should You Eat

Your dietary needs aren’t going to necessarily be the same as your training partners’. You may need to play around with your carb intake while training to find the ideal number for you. However, you can use some general guidelines to get started.

For runners who train hard and go on long runs, it is recommended to eat 5 to 8 grams of carbs per kilogram of bodyweight every day during training. That works out to roughly 2.3 to 5.5 grams of carbs for every pound of body weight.

For example, if you weigh 175 pounds, your daily intake should be around 400 grams of carbs every day to start. As your frequency and intensity increases, so should your carb intake. Ideally, you want to spread that intake out evenly throughout the day.

man running a race

What to Eat Before, During, and After the Race

If you don’t normally carb-load, you don’t want to start the day before or the day of the race. Likewise, you shouldn’t aim to get all your carbs in one meal. Both scenarios are a recipe for GI distress that could prevent you from performing your best. To give your body ample time to store up glycogen, start carb-loading at least three to four days before your race, gradually increasing your intake at every meal.

Before training or before a race, having a meal can help maintain your energy and keep you from feeling hungry while you run. Timing matters. The closer you get to your start time, the lighter you want to eat to avoid digestive upset. Some examples include:

  • 4+ hours before: 2 to 3 cups of pasta with meat sauce or with shrimp and veggies, tuna or turkey sandwich on whole wheat bread, or 3 ounces of grilled chicken with 6 ounces of rice, and a cup of fresh fruit
  • 2-3 hours before: A cup of cereal with 1/2 cup milk, a whole grain bagel with 2 tablespoons peanut butter, or a 12-ounce fruit smoothie
  • 1 hour before: 3 ounces of dried fruit like mango or cranberries, 7-ounce banana, serving of pretzels, or a granola bar

During your run, you’ll also need to fuel your body. Experts typically recommend getting anywhere from 30 to 60 grams of carbs per hour from gels, bananas, or sports drinks. This will help prevent glycogen depletion and keep you crushing your goals throughout the run.

After you've crossed the finish line, don't forget to refuel. Eating a meal or snack with simpler carbs within an hour after finishing helps rapidly replenish your muscles' glycogen stores. Examples include trail mix, a peanut butter and jelly sandwich, an energy bar, or pita and hummus.

Carb-loading Approaches

There are several methods you can use when increasing your carb intake. Three popular carbohydrate-loading approaches include:

Long taper: You might think of this as a slow load approach. Stop hard training 3 weeks before your race and taper your training down by two weeks before. During those 2 weeks, keep eating 3 to 5 grams of carbs per pound of body weight and reduce the amount of fat you eat. This forces your muscles to build a store of glycogen since you're not using it for training.

6-day load: For this approach, you start 6 days before your race. You spend the first 3 days eating a diet of about 50 percent carbs while gradually decreasing the amount of training you do. On the second 3 days, you increase to a diet made of 70 percent carbs and minimal (0 to 20 minutes) of exercise daily.

Rapid load: This approach starts about 24 hours before your race. Perform an glycogen-depleting exercise such as intense sprints. Then immediately begin a high-carbohydrate diet made of 5 to 6 grams of carbs per pound of bodyweight.