Oh... we also have a TV program devoted to stories of trying to cure/save various morbidly obese folks. In almost every case overeating of fattening foods is involved. The cure is invariably surgery to reduce the amount they eat. Some of the folk who weigh 500-800 lbs are catered to by relatives who weigh 250-400 lbs and ought to be seeking medical help themselves.
It is true that some metabolisms store food easily as fat, but still, large portions are the culprits.

I guess I am fortunate that I don't gain weight easily.... my brother has the opposite problem, and MUST limit his intake.