A vegetarian diet reduces the chances of developing kidney stones and gallstones. Diets high in animal protein cause the body to excrete calcium, oxalate, and uric acid—the main components of kidney stones and gallstones. A diet high in animal protein is responsible for the high rates (15% of men and 7% of women) of kidney stones in the United States, according to a peer-reviewed Nov. 15, 1999 study. [6]