Are you fat because you’re stressed? Or are you fat because of a virus you caught when you were a kid? A virus that can cause respiratory infections has been linked to childhood obesity. In the latest study, pediatricians found that fat children had antibodies in their blood that reveal an earlier infection with this virus. Blood tests of many obese adults also show evidence of this antibody. You might have even gotten fat because of the antibiotics you took to get RID of the virus. A new theory is that antibiotic use early in life has resulted in the disappearance, or extinction, of key bacteria in the human gastrointestinal tract that help keep the weight off. Some researchers think that antibiotic use in children may have resulted in the gradual disappearance of Helicobacter pylori, the ancient stomach bacteria that interact with hormones, to maintain energy. He has also observed that use of low dose antibiotics in farm animals fattens them up and there may be a similar result in human children repeatedly exposed to high-dose antibiotic doses at a very young age. BBC News quotes researcher Jeffrey Schwimmer as saying, "Many people believe that obesity is one’s own fault or the fault of one’s parents or family. This work helps point out that body weight is more complicated than it’s made out to be."