I'm unsure how your response indicates that obesity is a self-control problem. Participating in a camp for however long and dramatically changing food intake is bound to create results. But if people could get the same results on their own then they wouldn't need the camps in the first place.

In addition, the group of people that are aware that this type of service is available, and that can afford to take multiple days off work to go to a bootcamp exercise program and pay for the program, is a unique portion of the human population with significant commonalities in genetic markers, cultural backgrounds, and many other areas. Their accomplishments should not be used as an indicator for all of humanity (and of course neither should the events described in the original article).

For the person below who asked for references: Unfortunately I don't keep a file of research on obesity because I don't have the problem myself. So I can't directly point to the things I remember reading. But that is also why I started my comment with "I believe".