While the importance of carbohydrates is currently being challenged by many trendy diets, carbs are still king when it comes to the diet of an athlete. Carbohydrates are found in foods such as grains, fruit, dairy, vegetables, candy and sports food, in the form of sugar, starch or fiber. We commonly break carbohydrate-rich foods into the categories of simple carbohydrates (containing more sugar) or complex (containing more fiber). These foods were once the foundation of our food guide pyramid, representing the bulk of our food choices.


Carbohydrates from complex sources supply vital nutrients, such as antioxidants, niacin, folate, riboflavin, magnesium, selenium and fiber. Whole grains are a perfect example of complex carbs that supply many nutrients.

In fact, a University of Minnesota study showed a diet that gets carbohydrates from whole grains may reduce health risks. B vitamins supplied by grains assist with carbohydrate metabolism, making it a more efficient process — and the fiber supplied helps increase satiety, stabilize blood glucose, limit overeating and improve gastric regularity.

Of course, not all carbohydrates are optimal for health. Simple forms of carbohydrates supply sugar without other nutrients or fiber and therefore spike blood sugar, increase food cravings, promote obesity and lead to poor health outcomes. Like any food, it is important to choose nutritious sources in amounts appropriate for your body’s needs for the best health benefits.


Many foods supply carbohydrates. For health and performance reasons, we commonly classify these foods into two categories: simple and complex.

  • Simple carbohydrates are comprised of one or two sugar molecules and broken down very easily. While some sources of simple sugars occur naturally, such as in dairy and fruit, most come from added sugar sources.
  • Complex carbohydrates are made up of many sugar molecules and take much longer to be digested. Complex sources are often regarded as being healthier. This is easy when considering natural, unprocessed food sources, however, (for better or worse) we live in a world of manufactured foods which can make things slightly more complicated. It is important to look at labels as many new grain-free or plant-food alternatives can provide extremely variable levels of carbohydrates and may or may not be appropriate for your diet.

As shown above, carbohydrates can be unhealthy for your body in terms of general health, but are very good for performance. This is why athletes should be aware of nutrient timing specific to boosting performance and the amount of carbohydrates needed for the work being performed. Outside of training, athletes should focus on consuming carbohydrates from health promoting, complex sources.


Like the other two macros, fat and protein, carbohydrates supply our bodies with energy in the form of calories. Each gram of carbohydrate provides 4 calories. To put that in perspective, protein also supplies 4 calories/gram while fat provides 9.

While carbs are not the most calorically dense macronutrient, they are the preferred energy source for both mental and physical work. Carbohydrates are broken down to glucose in the body and utilized by almost every part of your body. In fact, the brain utilizes 120 grams, or roughly 60% of the body’s glucose daily, muscle tissue has roughly 500 grams of stored glucose ready for immediate physical use, kidneys use glucose to perform filtration functions, and the liver uses its 100 grams of stored glucose to metabolize food into additional ATP and regulate body functions between meals.

Excess carbohydrates, like any excess macronutrient, gets converted to and stored as adipose tissue. This ability to store glucose for immediate use makes it a very efficient energy source for performing quick bursts of physical and mental work. When it comes to performance, the rate of energy supplied by carbohydrates increases as the intensity increases because glucose can be produced anaerobically and very quickly. When exercising at 65% of VO2 max, carbs account for about half of the energy being used, which raises 2/3 when intensities increase to 85% of VO2 max.

Carbohydrate use in improving athletic performance has been shown time after time, and athletes with performance goals should avoid restricting dietary carbohydrates.


The amount of calories you need per day is highly individual. Some individuals consume 45% of their calories from carbohydrates while others get up to 80% from the macronutrient. This intake should depend on age, gender, nutritional status, lifestyle and health conditions.

For athletes, this number goes up based on hours per day spent in physical training. The more you train, the more carbs are advised. Most athletes need 6–7 grams of carbohydrate (CHO) per kilogram per day. Ultra-endurance athletes need more, and those training fewer than seven hours a week are fine consuming less.


Consuming carbohydrates is part of a balanced, health promoting diet when smart choices are made concerning the type and amounts consumed. Most adults should consume 45–65% of their daily calories from carbohydrates. Serious endurance athletes should focus on grams of carbohydrates per kilogram of body weight to get the energy needed to maintain training efforts without sacrificing health.

Take a look at your diet log to assess carbohydrate quality. Are most of your carbohydrates coming from whole, unprocessed sources that also provide fiber and other nutrients? Great. If you see simple, non-nutritive sugar sources are frequently recorded outside of training, aim to replace them with a higher quality carbohydrate source. If you’re struggling with how to make improvements to your carbohydrate intake, consult with a registered dietitian knowledgeable in that area.

Build healthy habits with the Low Carb Meal Plan. Sign up to receive daily tips and registered dietitian-approved recipes tailored to your personal calorie and carb goals. Go to “Plans” in the MyFitnessPal app to try our 28-day Low Carb Meal Plan.