Written on July 17, 2023 by Lori Mulligan, MPH. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
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Did you know that, according to the Centers for Disease Control and Prevention, being overweight or having obesity is linked with a higher risk of getting 13 types of cancer? These cancers, such as breast, liver, and pancreas, make up 40% of all cancers diagnosed in the United States each year.
Being overweight or having obesity doesn’t mean that you will definitely get cancer. But it does mean that you are more likely to get cancer than if you kept a healthy weight.
How Can Obesity Contribute to Cancer?
Being overweight and obese can cause changes in the body that help lead to cancer. These changes can lead to higher-than-normal levels of insulin, insulin-like growth factor, and sex hormones. The risk of cancer increases with any additional excess weight a person gains and the longer a person is overweight.
Other mechanisms, according to the National Cancer Institute, have been suggested to explain how obesity might increase the risks of some cancers.
- Fat tissue (also called adipose tissue) produces excess amounts of estrogen, high levels of which have been associated with increased risks of breast, endometrial, ovarian, and some other cancers.
- People with obesity often have chronic inflammatory conditions such as gallstones or non-alcoholic fatty liver disease. These conditions can cause oxidative stress, which leads to DNA damage and increases the risk of biliary tract and other cancers.
- Fat cells produce hormones called adipokines that can stimulate or inhibit cell growth. For example, the level of an adipokine called leptin in the blood increases with increasing body fat, and high levels of leptin can promote aberrant cell proliferation. Another adipokine, adiponectin, is less abundant in people with obesity than in people with a healthy weight. Adiponectin may protect against tumor growth.
- Fat cells may also have direct and indirect effects on other cell growth and metabolic regulators, including mammalian target of rapamycin (mTOR) and AMP-activated protein kinase.
Other possible mechanisms by which obesity could affect cancer risk include changes in the mechanical properties of the scaffolding tissue that surrounds developing tumors.
In addition to biological effects, obesity can lead to difficulties in screening and management. For example, women with overweight or obesity have an increased risk of cervical cancer compared with women of healthy weight, likely due to less effective cervical cancer screening in these individuals.
Major barriers to cervical sampling included a lack of adequately sized equipment and a lack of education and training.
How Do You Know If You’re Obese and Susceptible to Cancer?
BMI is one way of measuring whether you’re at a healthy weight, using your height and weight. BMI isn’t a perfect tool, but it can be used as a good starting point for thinking about weight. It can be used to tell whether you are in a healthy weight range, underweight, overweight, or obese for your height.
Ethnic background also influences what is considered a healthy weight.
For adults with a South Asian, Chinese, other Asian, Middle Eastern, Black African, or African-Caribbean ethnic background, a BMI of 23 or more is overweight, and a BMI of 27.5 or more is obese.
For adults not from these ethnic backgrounds, a BMI of 25 or more is overweight, and a BMI of 30 or more is obese.
Obesity and Cancer: What Can You Do?
One of the most important things you can do to decrease your cancer risk is to maintain a healthy weight.
There are steps you can take to help prevent obesity:
- Stay active. Aim for 150 minutes of moderate activity or 75 minutes of vigorous activity a week.
- Eat a healthy diet. Fill at least 2/3 of your plate with non-starchy vegetables, fruit, whole grains or legumes (beans and peas), and 1/3 or less with animal protein.
- If you drink alcohol, limit yourself to one drink per day if you are a woman, and two per day if you are a man.
- Get plenty of rest. Fatigue can make you want to eat more, and make unhealthy choices.
How Can Everlywell Help You with Weight Mangement?
The Everlywell Weight Care+ program, an online weight loss telehealth option, pairs a weight loss drug with regular clinician care, lab testing, and support for related conditions. The program includes:
- Access to GLP-1 prescriptions for qualified candidates
- Regular 1:1 virtual visits with a licensed clinician
- Quarterly at-home lab tests or supplements
- Lifestyle content and support for health conditions
Does Insulin Make You Gain Weight?
What Causes Obesity in America?
Obesity and Asthma: Is There a Connection?
- Obesity and cancer. Centers for Disease Control and Prevention. https://www.cdc.gov/cancer/obesity/index.htm. Last reviewed on July 13, 2022. Accessed on July 13, 2023.
- Obesity and cancer. National Cancer Institute. https://www.cancer.gov/about-cancer/causes-prevention/risk/obesity/obesity-fact-sheet#how-might-obesity-increase-the-risk-of-cancer. Last reviewed on April 5, 2022. Accessed on July 13, 2023.
- Clarke, Megan A. PhD; Massad, L. Stewart MD, et al. Challenges associated with cervical cancer screening and management in obese women: A provider perspective. Journal of Lower Genital Tract Disease 24(2):p 184-191, April 2020. | DOI: 10.1097/LGT.0000000000000506
- How does obesity cause cancer? Cancer Research UK. https://www.cancerresearchuk.org/about-cancer/causes-of-cancer/bodyweight-and-cancer/how-does-obesity-cause-cancer. Last reviewed February 14, 2023. Accessed on July 13, 2023.
- How does obesity cause cancer? MD Anderson Cancer Center. https://www.mdanderson.org/publications/focused-on-health/how-does-obesity-cause-cancer.h27Z1591413.html. June 2017. Accessed on July 13, 2023.