Physical fitness and vegetarian diets: is there a relation?

The available evidence supports neither a beneficial nor a detrimental effe ct of a vegetarian diet on physical performance capacity, especially when c arbohydrate intake is controlled for. Concerns have been raised that an emp hasis on plant foods to enhance carbohydrate intake and optimize body glyco gen stores may lead to increases in dietary fiber and phytic acid intake to concentrations that reduce the bioavailability of several nutrients, inclu ding zinc, iron, and some other trace minerals. There is no convincing evid ence, however, that vegetarian athletes suffer impaired nutrient status fro m the interactive effect of their heavy exertion and plant-food based dieta ry practices to the extent that performance, health, or both are impaired. Although there has been some concern about protein intake for vegetarian at hletes, data indicate that all essential and nonessential amino acids can b e supplied by plant food sources alone as long as a variety of foods is con sumed and the energy intake is adequate. There has been some concern that v egetarian female athletes are at increased risk for oligoamenorrhea, but ev idence suggests that low energy intake, not dietary quality, is the major c ause. In conclusion, a vegetarian diet per se is not associated with improv ed aerobic endurance performance. Although some concerns have been raised a bout the nutrient status of vegetarian athletes, a varied and well-planned vegetarian diet is compatible with successful athletic endeavor.