Piling on the pounds-especially around the waistline — is associated with increased breast cancer risk. [International Journal of Obesity and Related Metabolic Disorders, May 2000]. One study showed that women in their 50's who have gained more than 20 pounds had twice the risk of breast cancer. [Journal of the National Cancer Institute, 1996 88:650-60]. Body fat may convert adrenal hormones to estrogen after menopause, according to Katrina Claghorn, R.D., oncology dietician at the University of Pennsylvania Comprehensive Cancer Center in Philadelphia. Losing weight before menopause, however, lowers risk.