Stomach cancer in the United States has decreased over the last 50 years. It is still a major type of neoplasm in Japan, Eastern and Northern Europe, and parts of Latin America. Current concepts suggest that the reduction of gastric cancer in the U. S. stems from an increased consumption of foods with vitamin C on a year round basis, which is shown to antagonize the formation of putative gastric carcinogens. Risk factors for large bowel, breast, and prostate cancer are totally different from those for gastric cancer and thus are amenable to independent controls, with the goal of ultimately reducing the risk and preventing these major cancers in man. Current research aims to identify the nature of the mutagenic materials obtained during the frying of protein-containing foods. This process may be involved in the generation of carcinogens for cancer of the colon, breast, and prostate. Cancer of the colon is subject to somewhat different controlling elements than cancer of the breast because of the nature of the cell kinetics governing these tissues. Thus, the mechanism of action of diet involves lifestyle. The type, quality, and mode of cooking of food, particularly, play important roles in the etiology of the main human cancers in the gastrointestinal tract and the endocrine-sensitive organs.