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The Link Between Weight and Cancer Risk

blue measuring tape on top of scales

Managing weight is a challenge for many people in the US. In fact, according to the Centers for Disease Control and Prevention, more than 70% of American adults are overweight.

This puts them at higher risk for serious conditions, including diabetes, heart disease, and some types of cancer. According to research from the American Cancer Society, excess body weight is thought to be responsible for about 8% of all cancers in the United States, as well as about 7% of all cancer deaths.

Researchers have found that being overweight or obese is linked with breast cancer in women past menopause, colorectal cancer, and cancers of the endometrium, esophagus, kidney, and pancreas. And it might be linked with cancers of the gallbladder, liver, cervix and ovary, as well as non-Hodgkin lymphoma, multiple myeloma, and aggressive forms of prostate cancer.

Researchers think excess weight may increase the risk of cancer because it can lead to changes in the body that include:

  • Immune system function and inflammation
  • Levels of certain hormones, such as insulin and estrogen
  • Factors that regulate cell growth, such as insulin-like growth factor-1 (IGF-1)
  • Proteins that influence how the body uses certain hormones, such as sex hormone-binding globulin

But the connection between weight and cancer risk is complicated. Studies suggest the risk for some cancer types appears to be increased more for people who were overweight as children or young adults, than those who gained weight later in life. Also, having extra fat in the waist area may raise risk more for some cancer types than having extra fat in the hips and thighs.

Even though gaining weight can raise your cancer risk, it’s not clear whether losing weight reduces your risk. But there is growing evidence that weight loss might reduce the risk of breast cancer (after menopause), more aggressive forms of prostate cancer, and possibly other cancers, too.

We do know that avoiding weight gain is helpful, whether you are overweight now or not. If you’re carrying extra pounds, losing even a small amount of weight has health benefits and is a good place to start. Read tips from the American Cancer Society on making smart choices that can help you get to and stay at a weight that’s healthy for you.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.