John Harvey Kellogg, M.D. (February 26, 1852 – December 14, 1943) was an American medical doctor in Battle Creek, Michigan, who ran a sanitarium using holistic methods, with a particular focus on nutrition, enemas, and exercise. Kellogg was an advocate of vegetarianism and is best known for the invention of the breakfast cereal known as corn flakes with his brother, Will Keith Kellogg.