Everyone seems to know that being overweight and obese is bad for your health, but many people don’t know exactly why. Increased cancer risk is just one reason, but a big and important one.
Data indicate 14% of cancer deaths in men and up to 20% of cancer deaths in women are attributable to obesity. A 2002 comprehensive expert review by the International Agency for Research on Cancer (IARC), the same body that classifies carcinogens, concluded that, globally, obesity is a cause of 11% of colon cancer cases; 9% of postmenopausal breast cancer cases; 39% of endometrial cancer cases; 25% of kidney cancer cases; and 37% of esophageal cancer cases.
More recent data from the American Cancer Society (ACS) suggests that being overweight and obesity are also related to mortality from liver cancer, pancreatic cancer, non-Hodgkin lymphoma, and myeloma (cancer of plasma cells). Finally, most recently, an expert panel with the American Institute for Cancer Research (AICR) and World Cancer Research Fund (WCRF) conducted an updated review and concluded there is convincing evidence for a relation between obesity and esophageal, pancreatic, colorectal, postmenopausal breast, endometrial and kidney cancers. They found evidence was probable for a relation between obesity and gallbladder cancer, as well as, abdominal fat and an increased risk of pancreatic, endometrial and postmenopausal breast cancers. New evidence also suggests that obesity increases the risk of developing the aggressive forms of prostate cancer.
Overall, we estimate that being overweight and obesity causes approximately 20% of all cancer cases. Experts now estimate that the total health burden of being overweight and obesity, combined with a lack of physical activity and poor diet, equal – or might even exceed – that for cigarette smoking.