Lifestyle and Risk of Breast Cancer

Breast cancer is the most common invasive cancer among women worldwide, as well as in the United States. One in eight women in the U.S. will develop breast cancer over their lifetime.

For National Breast Cancer Awareness Month, we share key findings on the link between modifiable lifestyle factors and the risk of breast cancer from our recently released AICR/WCRF Third Expert Report: Diet, Nutrition, Physical Activity and Cancer: a Global Perspective. Learn about the science and how you can take steps to lower your risk or how you can support a loved one working to reduce their risk.


Alcohol: Drinking alcohol increases the risk of breast cancer.

  • Alcohol influences blood levels of estrogen and other hormones in ways that may make cancer more likely.
  • Alcohol is a recognized carcinogen. It can cause cellular damage that can trigger cancer development.

Weight: Carrying excess body fat increases the risk of post-menopausal breast cancer.

  • The presence of fat tissue causes inflammation, which can lead to cancerous mutation in healthy cells.
  • Having overweight or obesity increases blood levels of insulin and related hormones that can hasten the growth of cancer.

Physical Activity: Sedentary behavior is linked to an increased risk of cancer while being active decreases the risk of breast cancer.

  • Vigorous activity decreases the risk for pre-menopausal breast cancer.
  • Regular physical activity helps regulate hormones at optimum levels.
  • Evidence suggests that people who are physically active (both before and after diagnosis) have a greater chance of surviving breast cancer.

Breastfeeding: Breastfeeding your baby lowers the risk of breast cancer.

  • Breast cells undergo physical and hormonal changes during pregnancy and breastfeeding offers protection against cancer.
  • The shedding of tissue during lactation and elimination of breast cells at the end of lactation provide protection against cancer.

As diagnosis and treatment for breast cancer have improved, more women are surviving their diagnosis — and/or even becoming cancer-free. Now approximately 90 percent of those diagnosed with breast cancer survive five years or more after diagnosis.

Recommendations for Breast Cancer Survivors

The American Institute for Cancer Research (AICR) recommends that cancer survivors follow our recommendations for diet and physical activity when and if they are able to do so. Studies are finding that AICR’s recommendations may help with longer survival and reduce the risk for recurrence and lower risk of other chronic diseases like diabetes and heart disease.


“Reduce your Risk of Breast Cancer” American Institute for Cancer Research, Retrieved 10 October 2018. <>.

Marsha Fenwick, C.N.P.  R.R.T.

Marsha is not your typical nutritionist. She began her career 20 years ago as a Registered Respiratory Therapist. Later, she earned her certifications as a Registered Nutritional Consultant Practitioner, Certified Nutritional Practitioner, and Registered Orthomolecular Health Practitioner. Marsha is also a Certified Cancer Coach. Her clinical practice specializes in: sustainable healthy weight loss, digestive health, women’s hormones, diabetes, heart health, and cancer prevention and recovery. For more information and to book a FREE 15 minute consultation go to Marsha Fenwick Nutrition.