Hundreds of scientific studies support a diet that contains a variety of foods as the cornerstone of healthy eating. Most extreme diets that limit you to eating only one or two foods aren't healthy. The bottom line: There is no scientific evidence that any special diet can cure cancer.

Alternative diets that rely on special supplements or injections, fasting for extended periods, or enemas can be harmful to your health — especially if you're getting treatments for breast cancer. If you're in...