Athletic performance can be improved by eating special foods

In some cases, this is true. The best documented case for the use of special foods by athletes is consumption of carbohydrate-rich foods before endurance events. This approach was developed from studies by the Swedish exercise physiologist Per Olf Astrand. It involves building up carbohydrate stores known as glycogen in muscle. The size of these stores is an important determinant of endurance in aerobic exercise, like long-distance running. These stores can be built up by increasing the amount of carbohydrate consumed before an event. This is a safe strategy for any healthy contestant. If the muscle glycogen is first depleted by a low-carbohydrate diet, it can then be built up to an even greater extent with carbohydrate loading, but this technique often involves a phase of unhealthy eating.

There may be some advantage in a relative increase in protein intake by those engaged in muscle building exercises, but not if the basic protein intake is already plentiful (see PROTEIN-SUPPLEMENTED FOODS ARE BETTER FOR YOU).

The use of vitamin and mineral supplements to improve athletic performance has been widely advocated. There is no clear evidence of benefit. The difficulty, however, is that elite athletes are seeking very small increments in performance. It is almost impossible to obtain scientifically valid proof that performance with a supplement was significantly different to that with a placebo (dummy preparation) for a small number of performances. The practice may have to be accepted if athletes and their coaches believe it to be beneficial, and it does no detectable harm.

One should be wary of manufacturers who arrange for athletes to be taking their products at the time of a success. Later advertising campaigns may give the impression that a chance association is actually the reason for their success (a cause and effect relationship).