Hi, Thanks for writing in to us. Cancer is one of the diseases that has more unknown causes that known. Coming to breast cancer or cancer prevention as such, healthy food with all nutrients and antioxidants can be suggested to you. A sample diet plan to prevent cancer is below Breakfast: Add fruit and a few seeds or nuts to your whole grain breakfast cereal (such as oatmeal). Lunch: Eat a big salad filled with your favorite beans and peas or other combo of veggies. Always order lettuce and tomato (plus any other veggies you can) on your sandwiches. Order whole grain bread for your sandwiches. Have a side of veggies like cut up carrots, sauerkraut, or a piece of fruit. Snacks: Fresh fruit and vegetables. Grab an apple or banana on your way out the door. Raw veggies such as carrots, celery, cucumbers, jicama, peppers, etc. are great with a low-fat dip such as hummus. Keep trail mix made with nuts, seeds, and a little dried fruit on hand. Dinner: Add fresh or frozen veggies to your favorite pasta sauce or rice dish. Top a baked potato with broccoli and yogurt, sautéed veggies, or with salsa. Replace creamy pasta sauces, with sautéed vegetables or tomato sauce made with healthy olive oil. Dessert: Choose fruit instead of a richer dessert. Or a single square of dark chocolate. Hope this helps