Athletes must maintain sufficient caloric intake to meet energy requirements in order to prevent lethargy or fatigue. With their intensive training programs, caloric intake to meet energy needs may average 4,500 - 5,000/ day in men, and 3,000- 3.500/day in women. Athletes should use a food diary to record the previous week's intake in order to discuss it with a sports dietitian. Meals should include items from the five main dietary groups: bread and cereals, fruit and vegetables, meat and meat derivatives, daily products and butter, and fats and oils, to ensure a balanced diet. Monitoring body weight at regular intervals under standard conditions can be a guide to health and nutritional adequacy.
Here is a myth that high levels of dietary protein are needed to build muscle bulk and strength. Some athletes misguidedly consume up to 30% of their calories in protein, a strategy that does not improve performance and could in fact be detrimental. In fact, there is no evidence that most athletes need more protein than the sedentary person，but athletes in the power events may be the exception!
Large athletes, especially throwers, sometimes consume excess fat in their diet, while the opposite may be true for some endurance runners. Current dietary fads encourage reduction of fat to very low or zero levels. Such a strategy is not healthy, as free fatty acids provide the energy substrate during daily activities and recovery. In ultra - endurance events, fat becomes an increasingly important substrate as muscle and liver glycogen are consumed. There is also increasing evidence that ultra - endurance athletes should ingest a certain amount of fat to replace energy lost in competition, rather than eating only carbohydrates following competition.
