Surprising Causes of Weight Gain

4. Viral Infection

In some cases, a virus is responsible for weight gain. Several microbes promote adipogenesis, the formation of fat cells. A paper in the European Journal of Pediatrics explored the possibility of infectobesity, the hypothesis that infectious agents may cause obesity. Much research focuses on human adenovirus-36, the first virus reported to have adipogenic potential. Adenoviruses affect the respiratory and gastrointestinal tracts, mostly in children. A Finnish study noted that participants who gained excess weight during the 29-year study period were more likely to test positive for AD-36 than those who did not gain weight.