Book excerpt: The American Institute for Cancer Research (AICR) sponsored its second annual conference on nutrition and cancer. The theme was "Exercise, Calories, Fat, and Cancer" and the conference was held September 4-5, 1991 at the Ritz Carlton Hotel in Pentagon City, Virginia. This proceedings volume contains chapters from the platform presentations and abstracts from each poster presentation. Relationships among physical activity, calorie consumption, energy expenditure, dietary fat, and cancer are described in the context of epidemiologic, animal, and in vitro studies. Dietary recommendations to lower cancer risk are based on expanding evidence relating nutrition and cancer. Identification of the precise dietary contribution to disease is complicated by the concurrent genetic and environmental contributions, in addition to the inherent difficulties in gathering and interpreting epidemiologic data. Individual variations in cancer risk are the result of differences in genetic and environmental factors including sources and amounts of calories consumed, metabolism, and energy expenditure. Human and animal studies describing independent and combined influences of exercise, calorie restriction, and dietary fat on carcinogenesis are reported in this volume.