"Regular physical activity, weight control, and a heart-healthy diet are the best defenses for both men and women to prevent disease and promote a long and healthy life," says Byer, epidemiologist and professor of preventive medicine at University of Colorado School of Medicine.

Food, Genetics Interact
There are a whole host of benefits of a healthy diet that go beyond cancer. Fruits, vegetables, and whole grains -- the foundation of a healthy diet -- contain fiber, antioxidants, phytochemicals, and other healthy substances. These nutrient-dense foods are naturally fat free, very satisfying, low in calories, and the cornerstone of a weight-control eating plan.

The strongest evidence for cancer prevention lies in weight management and regular physical activity, according to Doyle. "Following the guidelines for alcohol (1 drink/day for women, 2 for men) and not smoking are also essential to wellness and disease prevention."