Obesity and Risk of Cancer

There is a growing body of evidence that excess body weight is an important risk factor for some cancers. The International Agency for Research on Cancer (IARC) examined the preventative effects of weight management on cancer risk and found sufficient evidence that obesity and overweight increase the risk of developing 13 cancers10(Figure 1). It is estimated that these account for 20% of all cancers.11 Based on another IARC report from 2012, the most common cancers attributable to excess weight in North America were postmenopausal breast (27%), endometrial (24%), kidney (16%) and colon (16%).39 In addition, a 2019 population-based study in the U.S. showed that the rates are on the rise for half of these obesity-related cancers – a contrast to declining or stable incidence rates of cancers related to other risk factors (ex. smoking). Alarmingly, they noted that rates are