Ha ha ha ha ha I started laughing the second I read the word "farting". I'm such a child.
Well, for me I'm pretty sure it's to do with gluten intolerance. One cause of wind is being unable to properly digest a certain food (gluten is a common one, as is lactose in milk). When I stopped eating wheat my gas just seemed to go away.
Since gluten intolerance has been implicated as, if not a possible cause of obesity, then certainly linked, I would not be surprised if that's the case for a lot of people.