You should read the book "Angry Fat Girls - 5 women, 500 lbs, and a year of losing it". I'm only about 1/2 way through and wow, very interesting. I grew up with an overweight mom and my older sister is morbidly obese. The stories the women tell about how they gained their weight were enlightening. Even after reading only 1/2 of the book I can see why my mom and sis have eaten their way to the weight that they are. It really ISN"T as simple as I love twinkies. Much, much deeper than that.
I only watched a few seasons of this show because I think the way they have the people lose the weight is unsustainable and unhealthy. Although I give kudos to the people on the show because most of them are so far gone that it is more important to get the life threatening weight off and then worry about the emotional parts of why they got so big.