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Losing Weight May Decrease Risk for Breast Cancer

You may have heard that roughly two thirds of adults in the United States are overweight or have obesity. But you may not know that some studies have linked obesity with certain cancers, including breast cancer in women.

Overweight is defined as having a body mass index (BMI) of 25 kg/m2 or above, and obesity is diagnosed when the BMI is 30 or above. Obesity increases the risk of many disorders, including certain cancers, diabetes, heart disease, stroke, and many others.

According to the American Cancer Society, the risk for postmenopausal breast cancer may be approximately 1.5 times higher in overweight women and two times higher in women with obesity. Likewise, weight gain is associated with higher cancer risk in postmenopausal women who are not on hormone therapy. It is estimated that approximately 316,000 women and 2,500 men in the United States were diagnosed with breast cancer in 2017.

The reasons for the association between higher BMI and cancer remain unclear. Many hormonal and metabolic factors have been investigated as possible links, including estrogen, insulin, leptin, chronic inflammation, and many others. Additional large studies are underway.

Weight Loss and Breast Cancer Risk

Meanwhile some (but not all) studies have shown that diet changes, weight loss and exercise can lower risk of developing breast cancer and improve survival after diagnosis.

“Weight loss may be a strategy for preventing breast cancer and for improving outcomes in people who get breast cancer, but we have much more to learn about this,” said Florencia Halperin, MD, an endocrinologist at Brigham and Women’s Hospital (BWH).

Dr. Halperin co-directs the BWH Center for Weight Management and Metabolic Surgery together with surgeon Ali Tavakkoli, MD. Recently they teamed up with the BWH Breast Center to help overweight and obese women lose weight as part of a breast cancer prevention strategy. 

“It is extremely challenging to lose weight, especially on your own,” said Dr. Halperin. Some people may find more success in a physician-supervised weight loss program. Effective strategies hinge on changes in nutrition, physical activity, and behavior – the three “pillars of weight management,” as Halperin calls them.

BWH offers multiple options for people who want to lose weight using strategies backed by scientific evidence. At both the BWH Program for Weight Management and at the Center for Weight Management and Metabolic Surgery, patients meet one-on-one with physicians to craft a weight loss plan tailored to the individual’s preferences and medical needs. Dr. Halperin and her team of physicians and dietitians teach participants about nutrition, exercise, medication options, and surgical approaches to weight loss.

The difference between the programs in part relates to the intensity of the intervention. At the Program for Weight Management, participants commit to attending weekly evening sessions, with both an individual and a group component. In both programs, evidence-based strategies are emphasized. Participants follow a calorie-controlled food plan, sometimes including meal replacements. A habit that is encouraged for everyone is keeping a food log. Many studies have shown that keeping this daily record makes people more likely to succeed at weight loss.

Dr. Halperin sees an advantage in such programs that are guided by professionals. “At BWH, we really focus on weight as a health issue,” said Dr. Halperin. “And we pride ourselves on being compassionate and respectful with all of the individuals that we work with.”

Weight Loss by the Numbers

If you are not sure whether you need to lose weight, talk to your doctor. Experts suggest that if you have obesity (BMI of 30 or more) you should lose weight. You also may need to lose weight if you are overweight (BMI of 25 or more) with one or more of these conditions:

  • Diabetes or prediabetes
  • High blood pressure
  • Abnormal cholesterol or triglyceride levels

Unsure of your BMI? You can calculate it here. A high BMI does not always indicate that you are overweight or obese. It may be due to extra muscle, bone, or water in the body. Weight distribution is also important to consider. Ask your physician for an assessment.

If you want to lose weight – which may have a favorable impact on your health, including your risk of developing breast cancer – you can try some scientifically backed steps:

  • Focus on the quality of your diet, by eating more fruits and vegetables and less refined or processed foods.
  • Keep a daily food log and commit to writing down everything that you eat.
  • Add aerobic exercise, which may help you shed more pounds. Plus, regular physical activity may also decrease breast cancer risk by 10 to 20%.

If you are interested in BWH weight loss programs, contact the Center for Weight Management and Metabolic Surgery at 617-732-7207 or the BWH Program for Weight Management at 617-732-8886. BWH Breast Center patients can learn more about a referral to weight management programs by calling the Breast Center at 617-983-7777.

-Sandy J.