The Complex Link Between Weight and Cancer

After tobacco, the most controllable risk factors for cancer are body weight, diet, and physical activity. The World Cancer Research Fund estimates that about 20 percent of all cancers diagnosed in the U.S. are related to body fat, physical inactivity, and poor nutrition, and thus could be prevented.

However, the links between body weight and cancer are complex and are not yet fully understood. Though it would be imprecise to say that being obese or overweight increases the risk of having cancer, research conducted by the American Cancer Society indicates that excess body weight may affect cancer risk through a number of mechanisms.

For example, excess body fat might affect the immune system function and inflammation, levels of certain hormones (such as insulin and estrogen), factors that regulate cell growth, and proteins that influence how the body uses certain hormones, such as sex hormone-binding globulin. Furthermore, evidence suggests that being overweight or obese raises the risk of cancer coming back after treatment and may lower the chances of survival for many cancers.

Particularly regarding breast cancer, we have learned that being overweight or obese after menopause increases the risk of developing that type of cancer. Before menopause, your ovaries make most of your estrogen, and fat tissue makes only a small amount. After menopause (when the ovaries stop making estrogen), most of a woman’s estrogen comes from fat tissue. Having more fat tissue after menopause can raise estrogen levels and increase your chance of getting breast cancer. Also, women who are overweight tend to have higher blood insulin levels. Higher insulin levels have been linked to some cancers, including breast cancer.

Breast cancer risk factors

As part of its guidelines on nutrition and physical activity for cancer prevention, the American Cancer Society recommends that people try to get to and stay at a healthy weight throughout life. The best way to stay at a healthy body weight is to balance how much you eat with how active you are. If you are overweight, the best way to get to a healthy body weight is to limit the calories you take in, and burn more calories through physical activity.

You can lower the number of calories you take in by eating smaller portion sizes; limiting between-meal snacks; and limiting foods and drinks that are high in calories, fat, and/or added sugars, and that provide few nutrients. If you drink alcohol, it is also advisable to limit your intake: drink no more than one drink per day for women or two per day for men.

Regarding physical activity, the American Cancer Society advises for adults to get at least 150 minutes of moderate intensity or 75 minutes of vigorous intensity activity each week (or a combination of these), preferably spread throughout the week. Doing some physical activity on top of your usual activities, no matter what your level of activity, can have many health benefits.

Aside from possibly reducing cancer risk, losing weight can have many other health benefits, such as lowering the risk of heart disease and diabetes. Losing even a small amount of weight has health benefits and is a good place to start.

The American Cancer Society does not endorse or promote any Herbalife Nutrition products or services. Most dietary supplements, including Herbalife Nutrition products, have not been shown to be beneficial for the prevention or treatment of cancer. People undergoing cancer treatment should check with their health care provider before using any dietary supplement.