There was a Nova episode called: "The Truth About Fat". It mentioned the case of a television show called "The Biggest Loser" where many overweight to severely obese people lost weight on a near competitive basis. One of the people is interviewed by Nova, he lost more than half his body weight going from 400 plus pounds to something like 180.

Almost none of the people festured on that series were able to keep the weight off. In the case of the man who was part of the Nova program, they established that while he was losing weight, his body-mind was in starvation mode and adjusted his basal metabolism downward. That low metabolic rate did not change. Long after he lost the weight and resumed eating 'normally', whatever that was, his base metabolism was far below that of a regular person.

I submit that until we know how to manage those 'set points' around metabolic rate and base weight, we won't have a handle on long term weight loss and maintenance.

Right now there are some contradictory appearances: That sustained weight loss and weight control are extremely difficult even when the subject has will power. Yet it is obvious that weight gain and obesity have magnified across the world in the past fifty years. So clearly somethings have changed. Right now there are many self anointed experts who claim that their big idea explains the situation. But do they?