Body Weight and Cancer Risk
Being overweight has been clearly linked to a higher risk of 13 different cancers. These include cancers of the:
- Breast (after menopause)
- Colon & rectum
- Gall bladder
- Multiple myeloma
Too much body fat works in a few ways to increase cancer risk. Extra body fat produces higher levels of certain hormones and proteins that may cause cancer cells to grow. These include insulin, leptin and estrogen, among others. In addition, fat cells make substances that cause chronic inflammation, which is linked to increased cancer risk. Research has also shown that people with extra fat around the waist (the “apple shape”), may be at higher risk because this fat causes even more cell growth, increasing the risk for cancer to form.
Body weight is measured using body mass index or BMI. BMI is a measure of body fat, based on a person's height and weight. This is a good place to start to evaluate your body weight and see where you fall on the chart, which classifies your BMI as underweight, healthy, overweight and obese.
A healthy diet, combined with regular physical activity and maintaining a healthy weight has been shown to reduce cancer risk. This triangle is thought to be the second most important step, after not smoking, to preventing cancer. A few studies have found that losing weight can help decrease the risk of weight-related cancers. The most convincing evidence for losing weight as a risk reduction technique comes from studies of people who have undergone bariatric (weight loss) surgery. In a sample of these patients, cancer death rates were 38% lower than people who were obese and did not undergo surgery.
Losing weight is no easy task. It takes a strong commitment to making big lifestyle changes. Seek support from friends, family, your healthcare providers, and weight loss programs. Investigate websites or applications (Apps) to track progress and motivate you. Get started by learning more at the American Cancer Society.
Resources to learn more about how diet, physical activity and weight are related to cancer
- American Institute for Cancer Research
- Take Control of Your Weight at the American Cancer Society website.
- Eat Healthy and Get Active at the American Cancer Society website.
- Dietary Guidelines for Americans, 2015-2020 from the USDA.
- The US Department of Health & Human Services 2008 Physical Activity Guidelines for Americans.
- NIH AARP Diet & Health Study: a study developed at the National Cancer Institute of the National Institutes of Health to improve our understanding of the relationship between diet and health.
- The European Prospective Investigation into Cancer & Nutrition (EPIC): A large study by the International Agency for Research on Cancer investigating the relationships between diet, nutritional status, lifestyle and environmental factors and the incidence of cancer and other chronic diseases.
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