The amount that each form of fuel contributes is highly dependent on the intensity of the activity. Therefore, the diet needs of each individual depend on how fit a person is, and how intense their activity is. This means that an active person who is not eating an adequate amount of protein for their body size will have trouble performing efficiently in their activities. Only about two to five percent of the body's general fuel needs comes from protein, which is very small compared to how much carbohydrate and fat the body burns. However, in endurance exercise, protein may contribute up to ten percent of calories burned.
Protein needs increase for intense exercisers, along with their calorie needs.
Therefore, experts recommend athletes eat 0.55 to 0.73 grams of protein per pound. But, contrary to popular belief, excessive protein in the diet is not necessary for most athletes. Your body can only metabolize so much protein per day, so even if you ate more than twice the RDA for protein in hopes of building extra muscle or sprinting faster, it would only amount to extra calories - your body would excrete the extra protein. A similar myth among athletes is that body-builders, in particular, need more protein in their diet. However, the opposite is true.