Lifestyle, in any part of the world, is associated with the occurrence of major chronic diseases, including coronary heart disease, hypertension, and stroke; many distinct types of cancer; and adult onset diabetes (11,22,70,75). One important element of lifestyle is tobacco use, which appreciably increases the risk of a number of chronic diseases (21). Other lifestyle factors relate to nutritional traditions, alcohol use, and exercise (11,30,58,60,70,71). The underlying evidence is, in part, based on the evidence of specific diseases in relation to dietary habits in a given geographic region, as well as changes in such disease occurrences in migrant populations from a low risk to a high risk area, and vice versa (25,42). Populations that customarily consume fruits and vegetables and also whole grain cereal products generally have a lower risk of cardiovascular diseases and specific types of cancer than populations with a lower intake of such foods, everything else being equal (63). In the last few years, research has provided mechanistic explanations as to the reasons for the protective effects of specific foods. This paper will emphasize the mechanisms whereby cancer risks are reduced by dietary modification.