It seems absurd to believe that obesity is contagious. After all, haven’t we been told that obesity is the result of poor food choices and lack of exercise? How in the world could obesity be contagious?
There are some researchers who believe that human adenovirus is partly responsible for the obesity epidemic. The theory that a virus could cause obesity began when a scientist noticed that chickens infected with an avian adenovirus were fatter than those chickens that were not infected. This was most interesting because some who were studying the human obesity explosion were becoming suspicious that more than poor diet and lack of exercise were causing humans to gain girth. The human adenovirus AD-36 has been found in obese humans. Studies with animals show that while not all human adenoviruses cause obesity in animals, there are several that do.