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.

There also seems to be yet another risk factor for obesity. Research has shown that obesity can be socially contagious. It seems that if you spend too much time with others who are obese, your chances of becoming obese rises. This means that your family and friends can make you fat simply by association. Supposedly, your risk of obesity increases 57% if you have a friend who becomes obese. If it is a sibling that is obese, the risk increases by 40%. Chances of becoming obese increase to 37% if your spouse becomes obese. The study found that risk was higher for same gender friends or family than for opposite gender friends and family. If this study is valid, the good news is that it works the same way for weight loss. When friends or family begin losing weight, it motivates you to lose weight also.

Whether either of these studies is valid is unknown. However, just to be safe, it might be a good idea to add hand washing to the list of ways to prevent obesity. Being mindful of the potential to gain weight as your friends and family gain weight might also serve as a protection in avoiding obesity. Since much of the data from both studies viewed as purely speculation, it is not known with any certainty that obesity is contagious.