Obesity is the UK’s biggest cause of cancer after smoking. Being overweight doesn’t mean that someone will definitely develop cancer. But, if a person is overweight they are more likely to get cancer than if they are a healthy weight.
In the UK it is estimated that 22,800 new cases of cancer are attributable to obesity (Cancer Research) Obesity is a risk factor for many types of cancers and on this page, we provide more information about the link between your weight and those cancers.
You’ll also find information on the benefits of losing weight, more specifically the benefits of losing weight through weight loss surgery.
What Is Known About the Relationship Between Obesity and Cancer?
Nearly all of the evidence linking obesity to cancer risk comes from large observational studies. These studies do not always present the clear picture we would like them to and it is impossible for most of them to definitively establish that obesity causes cancer. This is because obese or overweight people may differ from lean people in ways other than their body fat, and it is possible that these other differences—rather than weight alone—could explain their different cancer risk.
However, despite the limitations of these studies, there is consistent evidence that higher amounts of body fat are associated with increased risks of a number of cancers. In short, the weight as evidence is overwhelming. Here is a list of the cancers where an increased risk, linked to obesity, has been demonstrated.
Obese and overweight women are about 2-4 times as likely as ‘normal’ weight women to develop endometrial cancer. This is a cancer of the lining of the uterus. Furthermore, extremely obese women are about seven times as likely to develop the more common of the two main types of cancer (1).
Overweight or obese people are about twice as likely as ‘normal’ weight people to develop this type of oesophageal cancer. People who are extremely obese are more than four times as likely (2).
Gastric Cardia Cancer
A Cancer in the upper part of the stomach near to the oesophagus. People who are obese are nearly twice as likely as those who are ‘normal’ weight (3).
People who are overweight or obese are up to twice as likely to develop liver cancer. The link between obesity and cancer of the liver is stronger in men than in women (4,5).
People who are overweight or obese are nearly twice as likely to develop the most common form of kidney cancer (6).
Overweight and obese people have a slight (10% to 20%) increase in the risk of developing this (7).
The risk of this slow-growing brain tumour that arises in the membranes surrounding the brain and the spinal cord is increased by about half in the obese population (8).
People who are overweight or obese are about 1.5 times as likely to develop pancreatic cancer (9).
People who are obese are slightly (about 30%) more likely to develop colorectal cancer (10). The increase in risk is slightly higher in overweight/obese men than in women.
Compared with ‘normal’ weight people, people who are obese have a 60% increase in the risk of gallbladder cancer (11,12). The risk is higher in women than in men.
Among postmenopausal women, those who are obese have a 20% to 40% increase in the risk of developing breast cancer compared with women who are of a healthy weight (13). The risks differ according to whether women have used menopausal hormone therapy. Obesity is also a risk factor for breast cancer in men (14).
Higher BMI is associated with a slight increase in the risk of ovarian cancer, particularly in women who have never used menopausal hormone therapy (15).
Higher BMI is associated with a modest increase in the risk of thyroid cancer (16).
How Might Obesity Increase the Risk of Cancer?
On this page, we focus on the risk posed by overweight and obesity rather than exploring why the risk is increased. It is likely that the risk is increased for a number of reasons.
Several possible mechanisms have been suggested to explain how obesity might increase the risks of some cancers. These include the effect of obesity on fat tissue, fat cells, insulin and low-level inflammation that can cause damage over time.
Weight Loss Surgery and Cancer
As you have read the arguments for achieving and maintaining a healthy weight are powerful. In addition to reducing the risk of cancer, a healthy weight can prevent or cure a number of other weight-related health problems. You can read more about this here.
In modern society, we are seeing obesity rates increase, in the UK and around the world. Hand in hand with this we expect to see an increase in obesity-related cancer diagnoses.
Most people who are overweight or obese will have tried and failed over a long period of time to manage their weight through diet and lifestyle changes. For most people, these interventions only deliver short term benefits.
For people who have a body mass index above 30, it is likely that a medical weight loss programme or surgical intervention will be needed to bring their weight into a healthy range.
For those wanting to explore a medical weight loss programme, they can view the Slim Without Surgery programme that is offered by our sister clinic. Read more here.
At Healthier Weight we are specialist in weight loss surgery. We offer gastric bypass, gastric sleeve and gastric band surgery according to the specific needs of the patient. To learn more about these options please use the links provided here or call our team on 0800 313 4618.
- Setiawan VW, Yang HP, Pike MC, et al. Type I and II endometrial cancers: have they different risk factors? Journal of Clinical Oncology 2013; 31(20):2607-2618.
- Hoyo C, Cook MB, Kamangar F, et al. Body mass index in relation to oesophageal and oesophagogastric junction adenocarcinomas: a pooled analysis from the International BEACON Consortium. International Journal of Epidemiology 2012; 41(6):1706-1718.
- Chen Y, Liu L, Wang X, et al. Body mass index and risk of gastric cancer: a meta-analysis of a population with more than ten million from 24 prospective studies. Cancer Epidemiology, Biomarkers & Prevention 2013; 22(8):1395-1408.
- Chen Y, Wang X, Wang J, Yan Z, Luo J. Excess body weight and the risk of primary liver cancer: an updated meta-analysis of prospective studies. European Journal of Cancer2012; 48(14):2137-2145.
- Campbell PT, Newton CC, Freedman ND, et al. Body mass index, waist circumference, diabetes, and risk of liver cancer for U.S. adults. Cancer Research 2016; 76(20):6076-6083.
- Wang F, Xu Y. Body mass index and risk of renal cell cancer: a dose-response meta-analysis of published cohort studies. International Journal of Cancer 2014; 135(7):1673-86.
- Wallin A, Larsson SC. Body mass index and risk of multiple myeloma: a meta-analysis of prospective studies. European Journal of Cancer 2011; 47(11):1606-1615.
- Niedermaier T, Behrens G, Schmid D, et al. Body mass index, physical activity, and risk of adult meningioma and glioma: A meta-analysis. Neurology 2015; 85(15):1342-1350.
- Genkinger JM, Spiegelman D, Anderson KE, et al. A pooled analysis of 14 cohort studies of anthropometric factors and pancreatic cancer risk. International Journal of Cancer 2011; 129(7):1708-1717.
- 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.
- Li L, Gan Y, Li W, Wu C, Lu Z. Overweight, obesity and the risk of gallbladder and extrahepatic bile duct cancers: A meta-analysis of observational studies. Obesity (Silver Spring) 2016; 24(8):1786-1802.
- Renehan AG, Tyson M, Egger M, Heller RF, Zwahlen M. Body-mass index and incidence of cancer: a systematic review and meta-analysis of prospective observational studies.Lancet 2008; 371(9612):569-578.
- Munsell MF, Sprague BL, Berry DA, Chisholm G, Trentham-Dietz A. Body mass index and breast cancer risk according to postmenopausal estrogen-progestin use and hormone receptor status. Epidemiologic Reviews 2014; 36:114-136.
- Brinton LA, Cook MB, McCormack V, et al. Anthropometric and hormonal risk factors for male breast cancer: male breast cancer pooling project results. Journal of the National Cancer Institute 2014; 106(3):djt465.
- Collaborative Group on Epidemiological Studies of Ovarian Cancer. Ovarian cancer and body size: individual participant meta-analysis including 25,157 women with ovarian cancer from 47 epidemiological studies. PLoS Medicine 2012; 9(4):e1001200.
- Kitahara CM, McCullough ML, Franceschi S, et al. Anthropometric factors and thyroid cancer risk by histological subtype: Pooled analysis of 22 prospective studies. Thyroid2016; 26(2):306-318.