Although fat is the dietary substance most often singled out for increasing one's risk for cancer, protein also plays a role. Populations that eat meat regularly are at an increased risk for colon cancer,3 and researchers believe that the fat, protein, natural carcinogens, and the absence of fiber in meat all play roles. This holds true even in countries with low calcium intake. Increased calcium excretion increases risk for kidney stones. The truth is that athletes need only slightly more protein, which is easily obtained in the larger servings athletes require for their higher caloric intake.
Vegetarian diets are great for athletes.
As long as one is eating a variety of plant foods in sufficient quantity to maintain one's weight, the body gets plenty of protein. Protein requirements in humans. Committee on Diet, Nutrition, and Cancer of the National Research Council. Diet, Nutrition, and Cancer. Washington, DC, 1982. 5.