This sort of claim is made a lot, but I think it's based on flawed logic. First, most people fail at dieting because if they didn't have problems regulating their eating, they wouldn't be fat in the first place. Second, "eating skills" can be learned at any time, so the person coming off the Biggest Loser gets to be a skinny person who has to learn to eat right, vs a fat person who has to learn to eat right, which represents a significant "head start" on the process.