According to Dr. Weil, a healthy diet can help the body in its efforts to heal itself, and in some cases, particular foods can lessen the risks of serious illness. To help reduce your risk of some types of cancer, try the following:

• Avoid polyunsaturated vegetable oils, margarine, vegetable shortening, all partially hydrogenated oils and all foods that might contain trans-fatty acids (such as deep-fried foods).
• Minimize or eliminate consumption of foods with added sugar.
• Increase omega-3 fatty acid intake by eating more cold-water oily fish, freshly ground flaxseed and walnuts.
• Reduce consumption of animal foods and try replacing them with plant-based proteins such as whole soy products.
• Use hormone-free, organically produced products whenever possible.
• Eat plenty of fresh fruits and vegetables.
• Eat shiitake, enokidake, maitake and oyster mushrooms frequently.
• Drink green tea daily.

see his page here: http://www.drweil.com/drw/u/TIP04503/8-Ways-to-Prevent-Cancer.html