Confounding influences of varying fat, protein, and carbohydrate (CHO) levels, training habits, and lifestyle patterns make the interpretation of specific influences of the diet on endurance performance unclear. In general, exhaustion during prolonged, hard endurance exercise is tied to low muscle glycogen stores. Athletes in heavy training are urged to consume 70% of calories as CHO to maximize body CHO stores. A deemphasis in animal products with an emphasis in high-CHO plant foods would facilitate athletes in conforming to nutritional recommendations. Some female athletes may increase their risk of iron deficiency and/or amenorrhea if a restrictive vegetarian diet is adopted. In general, the high-CHO nature of the vegetarian diet can help the endurance athlete in heavy training maximize body glycogen stores and thus the ability to perform. The balanced vegetarian diet provides the athlete with added reduction in coronary risk factors while meeting all known nutritional needs.