egetarian diets are healthy and may confer protection against cardiovascular disease and aid weight control (here). However, much of the research investigating vegetarianism has focused on the sedentary individual. Intense exercise places unique stresses on the body and the ability to cope with the exercise stressor is largely dependent on the quality of the nutritional intake. Therefore the question of whether vegetarian diets affect the ability to undergo hard physical training is justified. A typical vegetarian has macronutrient ratios that differ to an omnivorous counterpart eating a Western diet. Generally vegetarians have an increased intake of carbohydrate and a decreased intake of protein, the main source of which in Western diets is animal protein. Because strength athletes have a high turnover of skeletal muscle, they require high intakes of dietary protein. It is therefore controversial as to whether a typical vegetarian diet is suitable for strength training.
The effects of vegetarian diets on endurance performance have been extensively reviewed in the scientific literature1. Because of the important role of carbohydrates in endurance training and the lower requirement for dietary protein compared to resistance training, endurance training seems well suited to a mainly plant based carbohydrate intake. Replenishment of muscle glycogen can be a barrier to endurance performance, and therefore elite endurance athletes consume diets with similar micronutrient ratios to the standard vegetarian diet. However, red meat is the primary source of iron in humans and vegetarians and especially vegans are at risk of developing iron deficient anaemia when undertaking frequent long-duration endurance training. Overall therefore, a typical vegetarian diet is not detrimental to endurance performance if adequate micronutrient intake is obtained.
However, resistance training and high intensity events require increased levels of protein in the diet due to greater protein turnover. Therefore the typical macronutrient ratios of the vegetarian and endurance diets are not suitable. Instead a higher protein, lower carbohydrate diet is more suited to such athletes, and therefore changes must be accommodated to a vegetarian diet in order to provide additional protein. Because good sources of protein may not be available to the vegetarian from food sources, supplementation with a suitable whey protein should be considered. In fact, such a strategy is employed by many omnivorous athletes due to the advantage of being able to increase protein intake without increasing fat intake. That whey protein is not suitable to vegans is not a problem because high quality proteins made from vegetables such as pea protein are also available, although soy protein should be avoided.
RdB
