There's another reason some women may want to hit the gym and watch what they eat.
A new study says, even a moderate decrease in weight could help reduce breast cancer risks.
Researchers at Fred Hutchinson Cancer Research Center used data from sedentary post-menopausal women who were overweight or obese.
They say, even a five percent weight loss can reduce the levels of circulating estrogens.
Those hormones are linked with an increased breast cancer risk.
Researchers say, a healthy diet is also key and that it's never too late to make lifestyle changes.