They found out that families assigned to an area where the majority of the population were obese or thin passed through changes in their physical form to conform to their new places of residence.

No kidding? :-o

Well, in a way, we tend to take in a number of things from our interactions with people. I'd probably get fatter if i live with someone who's obese. I find it hard to believe it's contagious though, just a function of how their lifestyle influences you.