About Breast Health

Avoiding Obesity and Weight Gain

Avoiding Obesity

Women should pursue a health strategy that will reduce the known breast cancer risk factors as much as possible, including avoiding obesity and weight gain, increasing physical activity and managing lifestyle choices. IARC estimates that excess body weight and physical inactivity account for approximately 25–33% of breast cancer cases.

Recent studies indicate that women who avoid being overweight reduce their risk of postmenopausal breast cancer. This risk is independent of the effect of physical activity. It is important for women to limit their weight gain in adult life and maintain a body mass index (BMI) of 18.5-24.9. Postmenopausal overweight /obesity is associated with an increased risk of breast cancer. There is an inverse relationship between obesity (BMI of 30 or higher) and breast cancer in pre-menopausal women and a direct relationship in post-menopausal women.

  • A large amount of abdominal fat may increase the risk of breast cancer
  • Obese women tend to have more abnormal mammography readings than non-obese women

Body Mass Index (BMI)

Being overweight with a BMI of 25 or higher, or obese with a BMI of 30 or greater, points to an increased risk of developing postmenopausal breast cancer. Women who have already had breast cancer may help reduce their risk of further problems by keeping their weight within the normal range.