How to Estimate Carbohydrate Needs for Athletes

By Jane Kirby, The American Dietetic Association

Calculating dietary carbohydrate requirements (and protein and fat for that matter) is based on a percentage of your total calories. Most athletes should get at least 60 percent of their calories in their diets from carbohydrates — the same as the general public. Some elite athletes, who have more specific energy needs, should base their requirements on their body weight.

Working muscles need energy. Carbohydrate is the form of energy that muscles prefer. Carbohydrates are stored in the body in limited amounts as glycogen in muscles and the liver.

When an exercising body uses all its glycogen, the athlete hits the wall and can no longer maintain exercise intensity. The technical term is glycogen depletion. Athletes describe it as feeling sluggish or stale. Often they think it’s because they’ve overtrained. But the real culprit is usually insufficient carbohydrate intake.

Carbohydrate needs are greater during training than for competition. The old practice of “carbo-loading” before an event doesn’t enhance performance as effectively as maintaining glycogen stores while training.

The following table helps you estimate your carbohydrate requirement based on your weight. Generally, athletes require 3.1 to 4.5 grams of carbohydrate per day per pound of body weight. To put that into perspective, nonathletes need only 1.8 to 2.3 grams per pound per day. Determine how heavily you’re training, then multiply the recommended grams of carbohydrate by your body weight to determine your daily carbohydrate requirement.

Carbohydrate Needs for Athletes
Training Level Grams of Carbohydrate per Pound per Day
1 hour of training per day 2.7 to 3.1 grams
2 hours of training per day 3.6 grams
3 hours of training per day 5 grams
4 hours of training or more per day 5.5 to 5.9 grams