Some researchers are looking at diet as a possible risk factor for breast cancer. Studies show that women in populations that consume a high-fat diet are more likely to die of breast cancer than women in populations that consume a low fat diet. But scientists still do not know for sure if a diet low in fat will lower the risk of breast cancer, or if any other specific dietary changes will actually prevent cancer.  Some studies point to lifestyle choices that may decrease a woman's risk of breast cancer. Exercise, especially in young women, may decrease hormone levels and contribute to a decreased risk. Breast-feeding also may decrease risk.  Other studies point to lifestyle factors that might increase a woman's risk of developing breast cancer. For instance, women who drink alcohol have a slightly increased risk. Gaining weight after menopause, especially after natural menopause and/or after age 60, also may increase a woman's risk.