Women who gain weight as they get older have a higher risk of breast cancer after menopause. Overweight women are exposed to more estrogen than lean women are. Estrogen is linked to the growth of breast cancer.

How much of a weight gain will increase your risk? One study found that women who gained 11 to 22 pounds after age 18 had an 18% higher risk of breast cancer after menopause than women who only gained four to five pounds. This risk jumped to 40% for women who gained 44 to 55 pounds.