How your weight can affect your breast cancer risk

Carrying excess weight can affect more than heart health, blood pressure and diabetes risk. It may also raise your risk of developing certain cancers, including breast cancer.

According to the Centers for Disease Control and Prevention (CDC), obesity is associated with 13 types of cancer. One estimate found that the number of obesity-related cancers diagnosed in the U.S. more than tripled from 1999 to 2020.

Among these cancers, breast cancer can be of particular concern after menopause. While the relationship between weight and breast cancer risk is complex, researchers are learning more about how excess body fat may elevate that risk.

Dr. Mark Jabro, an internal medicine doctor and obesity medicine specialist with Sharp Rees-Stealy Medical Group, explains how excess body fat may influence breast cancer risk and what women can do to support their overall health.

Body weight and breast cancer risk after menopause

Fat cells do more than store energy. They also produce hormones and other substances that affect how the body functions. After menopause, the ovaries no longer produce much estrogen, and fat tissue becomes a primary source of the hormone.

Having more fat tissue after menopause can raise estrogen levels and increase the chance of getting breast cancer, according to the American Cancer Society.

“Many people think of body fat as simply stored energy, but it's actually very active tissue," says Dr. Jabro. "It produces hormones and other substances that can influence many processes throughout the body."

In addition to producing estrogen, excess body fat can contribute to inflammation and metabolic changes. It can also raise insulin levels, which have been associated with some cancers, including breast cancer.

“Excess body fat can also contribute to chronic inflammation and changes in the body's metabolism,” says Dr. Jabro. “These changes may create an environment where cancer cells are more likely to grow and spread. Researchers are continuing to study these connections, but we know that maintaining a healthy lifestyle benefits overall health in many ways.”

Emerging research also suggests that fat cells surrounding a tumor may provide nearby cancer cells with fatty acids that support tumor growth.

Can losing weight lower your risk?

Scientists are still studying whether weight loss directly reduces breast cancer risk, but research so far is encouraging.

Studies show that women age 50 and older who lose weight and keep it off may reduce their risk of developing breast cancer. Even modest, sustained weight loss has been associated with a lower risk.

“We still need more research to understand exactly how weight loss affects breast cancer prevention,” Dr. Jabro says. “But the evidence we have suggests that staying active, eating well and maintaining a healthy weight may help lower cancer risk.”

Small steps can make a difference

Healthy lifestyle changes don’t have to feel overwhelming. Small, consistent habits can improve overall health and may help lower breast cancer risk.

• Maintain a healthy body weight.

  Body mass index, or BMI, is one tool used to indicate whether a person is at a healthy weight, but it does not provide a complete picture of a person’s health.

• Choose nutritious foods.

  Focus on fruits, vegetables, whole grains, lean proteins and healthy fats. Limit highly processed foods, added sugars and alcohol.

• Stay active.
  Adults should aim for 150 to 300 minutes of moderate-intensity activity or 75 to 150 minutes of vigorous activity each week.

• Talk with your doctor.
  Your doctor can help create a personalized plan and connect you with nutrition, exercise or weight management

  resources.

“Focus on progress, not perfection,” Dr. Jabro says. “Even small changes, when practiced consistently, can have a meaningful impact on your health.”

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