A sport dietitian can give advice about an athlete's eating pattern. If fatigue persists after the person changes their diet, they should check with a sports medicine physician who will assess other factors such as the training schedule, the amount of rest and other medical concerns. Although water is usually the best drink for athletes during exercise, sometimes water alone is not enough. Beverages such as juices, commercial sport drinks, fruit drinks and soft drinks contain water plus carbohydrates and electrolytes. During conditions of extreme sweating such as hot temperatures, humid conditions and prolonged endurance exercise to supply water and electrolytes.
Energy comes from carbohydrate, fat and protein.
Although some vitamins help the body to use energy, these vitamins are easily obtained from a high carbohydrate diet that includes a variety of foods from the four food groups. It is very important to re-fuel with a high carbohydrate meal or snack as soon as possible after an activity. Although it takes at least one or two days after a hard workout to fully refill the carbohydrate stores, athletes should start consuming carbohydrates within 15 minutes after the activity. The energy from excess protein and amino acid supplements is simply stored by the body as fat - not as muscle. Athletes get enough protein in their normal diet to allow for muscle growth.