I recently covered a study with results which showed that obesity may be socially contagious. So I was interested to see that another study reported on here points to a virus as a possible reason why some people become obese. A bug called AD - 36 is supposedly to blame, as it causes the fat cells in those who catch it go grow larger and multiply faster, resulting in excessive weight gain. While it is unethical to give purposely give the virus to humans, the bug has caused nearly all animals infected with it to put on weight. In addition, in one study 30% of obese participants whose blood was tested showed antibodies to the pathogen.

Personally, I think there are a variety of reasons why someone may become very overweight. It could be a social thing for some, while for others it could be the result of emotional eating or simply a high junk food diet mixed with a sedentary lifestyle. I find the virus explanation a little hard to believe though, because it doesn't explain why obesity rates have skyrocketed over the past coupe of decades. What do you think? Is obesity the result of a virus, or perhaps a gene? Is it a social disease or is it completely lifestyle related?