Nutrition for optimal performance during exercise: carbohydrate and fat.

Traditionally, high-carbohydrate diets have been recommended for endurance and ultra-endurance athletes. For many endurance events, the habitual consumption of a high-carbohydrate diet, with supplemental carbohydrate before and during exercise, is appropriate for many athletes. However, there are some situations for which alternative dietary options are beneficial. Diets relatively higher in fat than is currently recommended may be beneficial for exercise in which energy expenditure is high and time for recovery is limited, and for events in which athletes transport their food supply. The number of grueling events that challenge the limits of human endurance is increasing. Such events are also challenging the limits of current dietary recommendations, which may need to be expanded to allow for easier consumption of sufficient calories to minimize loss of lean body mass. The choice of diet for optimal physical performance depends on several factors, including type and duration of exercise, total energy expenditure, time for recovery, dietary preference of the athlete, and whether or not the sporting event is unassisted (and hence athletes are required to transport their food). A variety of diets ranging in macronutrient composition may be recommended based on these parameters.