Women who gained more than 45 pounds during adulthood increased their risk of post-menopausal breast cancer by 40 percent. Weight gained after menopause was only slightly related to post- menopausal breast cancer. Regular physical activity is also recommended to lower risk. It is not clear whether exercise acts directly on hormones or other factors to lower risk, or if its main benefit comes from the well-documented role of exercise in weight control. AICR recommends working toward a total of an hour of moderate exercise daily, but any amount of exercise is better for health than remaining a couch potato.
Studies also continue to examine the potential benefit of limiting alcohol consumption.
However, other studies suggest risk may begin at much lower levels of consumption. For overall health and lower breast cancer risk, women are advised to have no more than one standard alcoholic drink per day. The impact of dietary fat on breast cancer risk is unclear because different types of fat seem to vary in their effect. On the other hand, the report notes that the omega-3 fatty acids found in fatty fish and the monounsaturated fat in olive oil may help prevent cancer. A new study in The New England Journal of Medicine addresses the question of whether cancer is environmental or genetic.