Athletes (and regular exercisers), however, do need some extra protein with increased activity, but it should be increased in proportion to calories. People who are trying to gain weight, those wanting to build muscle, or those in heavy training do need additional protein, sometimes up to 150–200 grams daily, to stay in positive protein balance, especially when the calorie intake goes up near 3,000 a day. Some protein powders and amino acid formulas can be used to augment the protein balance. Aerobic-type exercises may slightly increase protein needs but not as much as body-building activities. Some extra protein intake, still along with a high-complex-carbohydrate, low-fat diet, will support muscle bulk while maintaining body fat levels. Young athletes need even more good protein foods than adults but should still focus on the complex carbohydrates for proper development. Again, avoid high-protein diets that exclude other important foods, particularly the complex carbohydrates, fruits, and vegetables. For building muscle, it may be better in many cases (especially when extra calories are not needed) to use good-quality supplemental amino acids or protein hydrolysates containing peptides to provide the cells and tissues with what they need to build and repair, rather than eating an excess of heavier flesh food proteins.

Complex carbohydrates provide the sustaining long-term energy, proteins the tissue building, and fats the lubrication and tissue support. This type of diet is also high in fiber, which allows good elimination. It is wise for serious athletes and health-conscious people to avoid excessive use of alcohol, regular cigarette smoking, and stimulants such as caffeine in coffee, tea, and cola beverages. Some iron-rich foods are especially important for female athletes or active runners, as their red blood cells may be broken down more rapidly. High-iron foods include red meats and liver (organic only), shellfish such as oysters, leafy greens, prunes, and mushrooms. With anemia, higher doses of supplemental iron may be needed.

Carbohydrate loading is a fairly new concept in the athletic world. It is based on the fact that complex carbohydrates such as grains, pastas, pancakes, and whole grain breads increase available energy, improving the stamina and ability to work. Here is how carbohydrate loading works. Four or five days before an endurance-type event, we increase our exercise and reduce our complex carbohydrate intake to about 40–50 percent of our diet, and eat more protein, fats such as dairy products and eggs, and fruit. This depletes the glycogen in our muscles and liver. Then, two to three days before the event, we increase complex carbohydrates to 70–75 percent of our diet, eating at least three big meals of carbohydrates, plus some proteins and fats. This increases the stored glycogen in the liver and muscles. Glycogen, the storage form of glucose, is easily converted to the simple sugar that is used by all cells and tissues for energy. Glycogen is then burned first for energy; if more energy is needed, fat will be utilized, and that works well too. If there is very low body fat, proteins in tissues may also be converted to energy. All of these macronutrients will need to be replaced. Some athletes report that carbohydrate loading increases sexual energy too. For any athletes with fatigue, carbohydrates will often help. Adding more grains, pasta, cereals, breads, vegetables, and fruit may also add strength and endurance.