Obesity and Cancer risks

The Connection Between Obesity and Cancer

October 7, 2020

The Connection Between Obesity and Cancer

While we previously had to combat the effects of the COVID-19 pandemic, it is important to stay informed about factors that affect long-term health and well-being such as the connection between obesity and cancer.

The international experience with COVID-19 has introduced more people to the concept of a pandemic. A pandemic is defined as a disease that is prevalent around the world. There have been pandemics throughout history. Some, such as the Spanish Flu, Ebola, AIDS, and now COVID-19, are remembered for their immense impacts. Many other pandemics become simple footnotes in history.

Obesity is a Disease and a Chronic Pandemic

Over the last 30 years, we have seen the emergence of a more insidious, chronic pandemic: obesity. The obesity pandemic has become a focus for health care professionals, epidemiologists, and policy-makers due to its ubiquity and the well-documented effects it has on quality of life and long-term health.

Being overweight and obesity are widespread chronic medical/metabolic disorders. A simple definition of these disorders is they are conditions in which a person has an excess amount and distribution of fat. This can be caused by energy imbalances (excessive calorie intake with inadequate exercise), genetic factors, medications, hormonal issues, and more.

Being overweight and obese are progressive disorders, where the majority of people suffering from them are likely to experience difficulty losing weight, as well as increased risk of developing multiple obesity-related medical problems.

Such obesity-related diseases include diabetes, heart disease, asthma, sleep apnea, headaches, joint inflammation, and multiple types of cancer. The obesity pandemic is so severe, in fact, that it’s estimated that nearly 70% of US adults over age 20 are overweight or obese, with obesity rates in young people (age 2 – 19 approaching 17% between 2011 - 2014. Weight loss surgery is associated with reduced cancer risks.

Link Between Obesity and Cancer Risks

The link between obesity and cancer risks have been demonstrated in multiple studies. Overweight and obesity are shown to increase the risk of developing around 13 types of cancers. According to the CDC, this accounts for up to 40% of all cancers diagnosed.

The following types of cancers are all linked to overweight and obesity:

  • Breast
  • Colorectal
  • Uterine/endometrial
  • Kidney
  • Esophageal
  • Pancreatic
  • Prostate
  • Gallbladder
  • Thyroid
  • Blood cell (multiple myeloma)
  • Liver
  • Stomach
  • Prostate

Inflammation and hormonal abnormalities are two major mechanisms related to obesity that are implicated in the increased risks of these cancers. Inflammation is a bodily response to injury, infection or certain diseases. An example of inflammation is seen in response to a wound, in which the area becomes red, swollen and painful. Inflammation has a role in healing, but when it becomes constant and widespread, it can cause cell damage.

These damaged cells need to be replaced, and this accelerated cell turnover in the setting of inflammation can increase the risk of multiple cancers; the more cells are having to be replaced at a time, the higher the risk that abnormal cells can multiply unchecked.

Multiple hormonal abnormalities are commonly present in the setting of obesity. In many patients with obesity, there is a degree of insulin resistance, meaning more insulin is required to have the intended effects. This results in “hyperinsulinemia”, or abnormally high insulin levels in the bloodstream.

Insulin is a hormone that regulates blood sugar and is considered one of the most anabolic hormones, triggering growth of multiple cells in the body and storage of energy in fat cells. Hyperinsulinemia can trigger increased cell production and increased energy storage, increasing the risk of development of multiple cancers as well as further weight gain, which perpetuates the cycle.

Excess insulin also affects other hormone levels, such as estrogen. Fat cells make estrogen, and estrogen levels tend to be higher in patients with obesity. Higher estrogen levels increase the risks of breast and endometrial cancers. There are multiple other mechanisms that link obesity and different cancer risks.

Use the Strategy of Good Health

The bottom line is that good health is the best strategy to decrease these risks. The best recipe for success has multiple ingredients. Aim for at least 150 minutes of moderate activity per week. Use a fitness app to keep a food journal, and aim for at least 65 grams of protein daily.

Meals should be portion-controlled to fit on a side dish. Half of each meal should include a lean protein source, with the other half of each meal including non-starchy vegetables, whole grains, legumes and fruit. Limit alcohol to no more than 1 drink per day for women and 2 drinks per day for men.

For people with significant obesity who make these changes but do not see lasting weight loss, more powerful options for weight loss and metabolic improvements should be considered. Such options include bariatric surgical and endoscopic procedures, which can result in significant excess weight loss, improved metabolic health, improved quality of life, and decreased risk of multiple obesity-related medical problems.

There are resources to help guide patients toward better health and improvements in metabolic health, including nutritionists, physicians, exercise specialists, and bariatric surgeons.


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Calle EE, Kaaks R. Overweight, obesity and cancer: epidemiological evidence and proposed mechanisms. Nature Reviews Cancer. 2004;4(8):579–591.

Calle EE, Rodriguez C, Walker-Thurmond K, Thun MJ. Overweight, obesity, and mortality from cancer in a prospectively studied cohort of U.S. adults. The New England Journal of Medicine. 2003;348(17):1625–1638.

Reeves GK, Pirie K, Beral V, Green J, Spencer E, Bull D. Cancer incidence and mortality in relation to body mass index in the million women study: Cohort study. British Medical Journal. 2007;335(7630):1134–1139.

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siddharth kudav


Dr. Siddharth Kudav is a board-certified general surgeon with fellowship training in laparoscopic and robotic bariatric surgery. He performs laparoscopic and robotic gastric bypass, sleeve gastrectomy, revisional bariatric surgery, hiatal hernia repair, anti-reflux surgery, hernia surgery, and bariatric endoscopy at Advanced Surgical & Bariatrics of NJ, PA.