WASHINGTON — Obesity is on course to overtake tobacco as the leading risk factor for cancer in America, according to a report issued today. Moreover, the risk for cancer increases even with modest weight gain, said Walter C. Willett, M.D., Ph.D., of the Harvard School of Public Health. He said excess body fat increased the risk for cancers of the colon, kidney, and pancreas, adenocarcinoma of the esophagus and endometrium, and breast cancer in postmenopausal women. That was the major finding from a mega-analysis of more than 7,000 published studies conducted by a 21-member board assembled by the American Institute for Cancer Research and the World Cancer Research Fund International. The results of the analysis, Food, Nutrition, Physical Activity, and the Prevention of Cancer: A Global Perspective, were released at a press conference here. Dr. Willett pointed out that obesity is now the second leading cause of cancer, just behind tobacco, because ‘obesity increases the risk of so many cancers and because two-thirds of Americans are overweight.’ He and his colleagues predicted that over the next decade ‘obesity will become the number one risk factor for cancer’ as obesity increases and the number of smokers […]