Scientists have long thought obese people have a higher cancer risk, possibly because fat cells produce hormones that might lead to the disease.Women who have their stomachs stapled can cut their cancer risk by up to 40% – but men don’t seem to reap the benefit, a study shows.Being overweight as a young adult increases the risk for pancreatic cancer. That’s according to a study published Wednesday in the journal of the American Medical Association.The risk of cancer leveled off for those who became overweight or obese at age 40, and the risk became insignificant for those whose excessive weight gain did not start until after age 50.