The study looked at the body mass index of people from 184 countries in 2002 and contrasted it with cancer rates for those people in 2012. The researchers focussed on cancers which are linked to obesity — breast cancer, colon cancer, kidney cancer and pancreatic cancer. They estimate that 3.6 percent of cancer cases were caused by obesity. If you take that percentage and extrapolate it to global cancer statistics, you are looking at as much as half a million cancer cases triggered by obesity, each year.
Women are more likely to get cancer if they are obese, with 5.4 percent of women presenting with cancers caused by obesity. The United States has the highest rate of obesity related cancers, with over 100,000 in 2012. Postmenopausal breast cancers and some uterine cancers are very closely tied to obesity, which explains the higher percentage for women.
Researchers partially understand why obesity causes cancer. Obesity creates various unusual actions within the human body, including an overload of certain hormones. Those hormones can contribute to cancer, particularly breast cancer. One of those hormones is insulin-like growth factor 1, which has been linked to pancreatic cancer.
Doctors recommend a healthy diet and exercise to reduce your risk of getting cancer.