Overweight- and Obesity-Related Cancers

You might consider extra weight a risk to your heart, energy levels, or joints. But you may not know much about body weight's role in a less obvious risk: cancer.

"In the last few years, the relationship between excess weight and cancer has really started to get out there into the public domain," Neil Iyengar, MD, an investigator with the Breast Cancer Research Foundation and an attending physician at the Memorial Sloan Kettering Cancer Center in New York, told Health. There's been a realization, backed by research, "that maintaining weight is important not just for cardiovascular health."

In the United States, being overweight or obese contributed to about 28,000 new cancer diagnoses in men each year and 75,000 in women between 2012 and 2015. And according to a study published in 2019 in CA: A Cancer Journal for Clinicians, globally, more than 544,000 cancer diagnoses are due to excess weight.

Being overweight or having obesity is linked to a higher risk of 13 different types of cancer, as identified in a review published in 2016 by the International Agency for Research on Cancer (IARC).

Here are the 13 cancers linked to extra weight, plus why that excess weight makes a difference.

The Link Between Body Weight and Cancer Risk

Overweight- and obesity-related cancers accounted for 40% of all cancers in the United States between 2005 and 2014, according to a report published in 2017 by the Centers for Disease Control and Prevention (CDC).

But the relationship between body weight and cancer risk is not quite as simple as "lose weight, avoid cancer." Nor does everyone who carries a few extra pounds end up with a cancer diagnosis.

Additionally, most research linking cancer to body weight doesn't follow people who shed pounds but rather folks who never lost weight. So, it's tough for researchers to identify what would happen to your cancer risk if you slim down.

But generally, maintaining a healthy body weight and shedding excess pounds can help prevent certain types of cancer, especially those linked to obesity.

"The best advice is first to avoid further weight gain," Graham Colditz, MD, deputy director of the Institute for Public Health at Washington University in St. Louis, told Health in a prior interview. "Weight loss will lower the risk of diabetes, heart disease, and stroke as well as cancer. So, there are many good reasons to get back into shape, balance the food we eat with sufficient exercise, and avoid more weight gain or get some pounds off."

Here's what you should know about the 13 cancers identified by the IARC that are linked to being overweight or obese.

01 of 13

Breast Cancer

Excess weight increases the risk of breast cancer. The researchers found that risk only occurs in women after menopause, the natural process in which menstrual cycles stop, usually between the ages of 45 and 55.

Postmenopausal women who are obese have about a 20% to 40% greater risk of developing breast cancer than women at a healthy weight. Each additional five points you go up on the body mass index (BMI) scale increases that risk by 12%. Your BMI is your height-to-weight ratio. A BMI of 18.5-24.9 is considered normal. Anything above that indicates overweight, and a BMI over 30 indicates obesity.

Standard Disclaimer

Body Mass Index, or BMI, is a biased and outdated metric that uses weight and height to make assumptions about body fat and, by extension, your health. This metric is flawed in many ways and does not factor in your body composition, ethnicity, sex, race, and age. Despite its flaws, the medical community still uses BMI because it’s an inexpensive and quick way to analyze health data.

Fat tissue produces the hormone estrogen. During and around menopause, the body makes less and less estrogen than normal. So, after menopause, fat becomes the main source of estrogen. But estrogen also increases the risk of some breast cancers. Excess body fat can mean extra estrogen, thereby increasing breast cancer risk.

Fat tissue can be "unstable and inflamed," added Dr. Iyengar. Chronic inflammation, like the low-grade type caused by carrying excess weight, might stimulate the growth of cancerous cells.

Because the breast is mostly composed of fat tissue, it's likely that this type of "fat tissue dysfunction" is involved in the link between breast cancer risk and weight, said Dr. Iyengar.

02 of 13

Ovarian Cancer

Cancer of the ovaries is also slightly more common among women with a higher BMI than normal. A five-point increase in BMI increases a woman's risk by 10%.

Like breast cancer, estrogen produced in excess fat tissue may contribute to ovarian cancer risk. Metabolic dysfunction like insulin resistance may also be a risk factor, said Dr. Iyengar.

03 of 13

Endometrial Cancer

The endometrium is the tissue that lines the inside of the uterus. Endometrial cells can become malignant, which causes endometrial cancer.

The condition is two to four times more likely among overweight and obese women than among normal-weight women. Endometrial cancer is seven times more likely in women who are severely obese than others.

As with breast and ovarian cancers, estrogen, which fat tissue produces in excess, may contribute to endometrial cancer risk. Some evidence also suggests a link between endometrial cancer and insulin resistance.

"Both hormonal and metabolic processes lead to the production of endometrial cancer," explained Dr. Iyengar.

04 of 13

Colon Cancer

People with obesity are nearly 30% more likely to develop colorectal cancer than people with a normal BMI. In a review published in 2013 in PLoS One, researchers presented two theories as to why body weight seems to affect colorectal cancer risk.

The first theory points to insulin resistance, which causes the body not to use insulin properly. If untreated, people with insulin resistance develop high blood sugar. Being overweight or obese is a risk factor for developing insulin resistance. Research has linked insulin resistance to an increased risk of colorectal cancer.

The second theory has to do with hormone production and inflammation. Fat tissue releases hormones called adipokines that promote cell growth, including the growth of cancerous colorectal cells. The colon is also surrounded by fat tissue, added Dr. Iyengar.

"If there is chronic, low-grade inflammation from fat tissue, that can lead to the development of colon cancer," said Dr. Iyengar.

05 of 13

Esophageal Cancer

Carrying extra weight makes you twice as likely to develop a specific type of cancer in the esophagus or throat called esophageal adenocarcinoma. Esophageal adenocarcinoma starts in throat cells that produce mucus and other fluid.

Gastroesophageal reflux disease (GERD) is a risk factor for this type of cancer, and GERD is more common in obese people. GERD causes stomach acid moves into the lower part of the esophagus.

Some evidence suggests that chronic, low-grade inflammation caused by fat tissue all around the body may contribute to cancer of the esophagus, added Dr. Iyengar.

"Our knowledge of obesity and esophageal cancer is evolving," noted Dr. Iyengar.

06 of 13

Gallbladder Cancer

Your gallbladder is a small organ near your liver that releases bile, which helps with digestion, particularly fats.

There's about a 20% increase in your risk of gallbladder cancer if you're overweight. And if you have obesity, there's a 60% increase.

A history of gallstones is one of the most significant risk factors for gallbladder cancer. Gallstones are clumps of bile and dissolved cholesterol in the gallbladder or bile duct, the tube that carries bile to the small intestine. Gallstones are more common among people with obesity.

07 of 13

Kidney Cancer

The risk of renal cell cancer, a common type of kidney cancer, is nearly twice as high in people who are overweight or have obesity than in people with a normal BMI.

As with other overweight- and obesity-related cancers, insulin resistance may contribute to your risk of kidney cancer.

"The kidneys are in a bed of fat," explained Dr. Iyengar. And inflammation in that fatty tissue may also be "influential on what's going on in the kidney itself."

As of December 2022, research—including some by Dr. Iyengar—aims to explain the relationship between weight and kidney cancer.

08 of 13

Liver Cancer

The risk of liver cancer is also twice as high among people who are overweight or have obesity than in people with a normal BMI.

Researchers look to other causes of liver cancer for details about the link with body weight, said Dr. Iyengar. For example, hepatitis C, a viral liver infection, can progress to liver cancer. Cirrhosis, scarring on the liver, is also a risk factor. Hepatitis or alcohol use disorder can cause cirrhosis.

Hepatitis C and cirrhosis can create chronic inflammation, like that caused by carrying too much weight, explained Dr. Iyengar. That inflammation may spark the growth of cancer cells.

09 of 13

Meningioma

Meningioma is a type of brain tumor that starts in the meninges, membranes covering the brain and spinal cord. Meningioma usually grows slowly.

Meningioma risk is around 20% higher in overweight people and 50% higher in obese people than average.

According to one study published in 2019 in Neuro-Oncology, estrogen increases the risk of meningioma, and fat tissue produces excess estrogen. However, there "really isn't any good explanation" for the link between weight and meningioma, according to Dr. Iyengar.

"A lot of research needs to be done there," said Dr. Iyengar.

10 of 13

Multiple Myeloma

Multiple myeloma is a type of blood cancer that affects plasma cells in the bone marrow.

Multiple myeloma is just 10% to 20% more likely in people who are overweight or obese than others.

According to one study published in 2016 in Frontiers in Endocrinology, the inflammation-promoting chemicals made by fat cells could help multiple myeloma grow since there are fat cells in the bone marrow.

11 of 13

Pancreatic Cancer

People who are overweight or have obesity have a 50% higher risk of pancreatic cancer than people with a normal BMI.

The pancreas produces insulin, making the organ a major player in metabolic health. Problems with insulin production, like insulin resistance, may increase pancreatic cancer risk.

Additionally, the pancreas is surrounded by fat, which can produce inflammation and trigger pancreatic cancer cell growth, said Dr. Iyengar.

12 of 13

Stomach Cancer

People with obesity are twice as likely to develop gastric cardia cancer, a condition affecting the upper portion of the stomach, than people with a normal BMI.

It's possible that disruptions to the gut microbiome, or the balance of healthy and harmful microorganisms in your digestive tract, could play a role, explained Dr. Iyengar.

The chronic, low-grade inflammation caused by excess fat tissue may also be involved, added Dr. Iyengar.

13 of 13

Thyroid Cancer

The thyroid is the butterfly-shaped gland in your neck, just below the Adam's apple, that helps control your metabolism.

People who are overweight or have obesity see a 26% and 30% increase in their risk of thyroid cancer, respectively.

Per the American Cancer Society, healthcare providers diagnose about 44,000 people with thyroid cancer in the United States yearly. About 12,000 are men, and 32,000 are women.

According to one study published in 2019 in Scientific Reports, chronic low-grade inflammation and increased thyroid stimulating hormone (TSH) are some factors linking high BMI to thyroid cancer.

A Quick Review

Being overweight or having obesity can increase your risk of cancer, sometimes drastically.

Researchers don't know why excess weight contributes to these cancers, but one of the most significant risk factors is the inflammation caused by excess fat tissue. Hormones such as insulin and estrogen, made in fat, also come into play.

It isn't clear whether losing weight would reduce risk. Still, losing weight can lower your risk of many other chronic diseases and protect you against cancer.

Was this page helpful?

Thanks for your feedback!

Tell us why!

14 Sources

Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Islami F, Goding Sauer A, Gapstur SM, Jemal A. Proportion of Cancer Cases Attributable to Excess Body Weight by US State, 2011-2015. JAMA Oncol. 2019;5(3):384-392. doi:10.1001/jamaoncol.2018.5639
Sung H, Siegel RL, Torre LA, et al. Global patterns in excess body weight and the associated cancer burden. CA Cancer J Clin. 2019;69(2):88-112. doi:10.3322/caac.21499
Lauby-Secretan B, Scoccianti C, Loomis D, et al. Body Fatness and Cancer--Viewpoint of the IARC Working Group. N Engl J Med. 2016;375(8):794-798. doi:10.1056/NEJMsr1606602
Steele CB, Thomas CC, Henley SJ, et al. Vital Signs: Trends in Incidence of Cancers Associated with Overweight and Obesity - United States, 2005-2014. MMWR Morb Mortal Wkly Rep. 2017;66(39):1052-1058. doi:10.15585/mmwr.mm6639e1
Anderson AS, Renehan AG, Saxton JM, et al. Cancer prevention through weight control-where are we in 2020?. Br J Cancer. 2021;124(6):1049-1056. doi:10.1038/s41416-020-01154-3
National Cancer Institute. Obesity and cancer.
Ma Y, Yang Y, Wang F, et al. Obesity and risk of colorectal cancer: a systematic review of prospective studies. PLoS One. 2013;8(1):e53916. doi:10.1371/journal.pone.0053916
American Cancer Society. Esophageal cancer risk factors.
World Cancer Research Fund International. Gallbladder cancer.
Zahra N. Link of obesity and gallstones formation risk. AOWMC. 2019;9(5):118-120. doi:10.15406/aowmc.2019.09.00285
Muskens IS, Wu AH, Porcel J, et al. Body mass index, comorbidities, and hormonal factors in relation to meningioma in an ethnically diverse population: the Multiethnic Cohort. Neuro Oncol. 2019;21(4):498-507. doi:10.1093/neuonc/noz005
Falank C, Fairfield H, Reagan MR. Signaling Interplay between Bone Marrow Adipose Tissue and Multiple Myeloma cells. Front Endocrinol (Lausanne). 2016;7:67. doi:10.3389/fendo.2016.00067
American Cancer Society. Key statistics for thyroid cancer.
Kwon H, Han KD, Park CY. Weight change is significantly associated with risk of thyroid cancer: A nationwide population-based cohort study. Sci Rep. 2019;9(1):1546. doi:10.1038/s41598-018-38203-0

13 Cancers Associated With Obesity