I think our relationship with food is a very complicated one, particularly in the developed world where food is more varied and plentiful. Even supposedly "normal" people who don't have obvious eating disorders can get caught up in a cycle of silly diets, expensive "low calorie" foods, etc. etc. There are so many reasons why people become overweight or get into unhealthy patterns of eating:
Parents who "reward" children with food - setting up a pattern for life
The marketing of unhealthy/addictive foods and drinks
Feelings of lack of control in a parent/child relationship
The vast choice of food available
Depression, leading to over or under eating
Lack of exercise ... etc. etc.
Whatever the reasons, I don't like these sorts of voyeuristic programmes that seem to intrude on the misfortunes of others.