Publisher Summary Nutrition is related to the development of cancer in three ways: (1) food additives or contaminants may act as carcinogens, cocarcinogens, or both; (2) nutrient deficiencies may lead to biochemical alterations that promote neoplastic processes; and (3) changes in the intake of selected macronutrients may produce metabolic and biochemical abnormalities, either directly or indirectly, which increase the risk for cancer. Specific carcinogens play a minor role as initiators in the relationship between nutrition and the development of cancer. This chapter covers six types of cancer: large bowel cancer, colon carcinogenesis, stomach cancer, cancer of the upper alimentary and respiratory tract, cancer of the pancreas, and breast cancer. In four of these—breast, large bowel, stomach, and head and neck—the epidemiologic evidence is overwhelming that nutritional factors have a major etiological role. Dietary factors are also implicated in the etiologies of the two remaining types of cancer—pancreas and prostate—but the epidemiologic evidence is not overwhelming. The chapter also presents an evaluation of the status of the relationship between nutrition and cancer in man, discusses the use of animal models to determine if the etiological factors established for man can be modified in an experimental setting, and makes recommendations for additional research and possible preventive measures.