How do people get to be SO overweight?

I, like many people, have started to try and lose weight for the New Year. I was trying (although not that hard) to lose weight prior to this, but the holidays were a train wreck for my diet. Fried french toast cannot be considered healthy in any diet. I am to the point where I am heavily overweight but not obese. I am not even talking about people who are 300 lbs. I am talking about people who are 500 lbs. I am talking about people who are so overweight that they who can't get out of bed. Most people I know who are severely overweight have had some sort of injury that led to inactivity and then that became their lifestyle or they have some sort of lasting physical effects. I can understand that. But to get so large that it is impacting your life, takes some time. And some pretty consistent eating. Is it just so out of control that they can't stop themselves, do they love food that much. I guess it is just like any other risky behavior, it is hard to take control of. I read an article once that most heart attack patients will not change their behavior or take their medicine following a heart attack. They article was on why we won't change our eating habits. It is hard and I think what it is, is that we tie so many things to eating. It is a social event to go out to dinner, to have a family meal, etc. Maybe the key is really to make out family time something different and make eating less of an event. It is such a sensory experience though. Maybe they need a pill like Chantix for eating that blocks the sensory receptors in the brain so our brain doesn't know that it like to eat. Hard to say...