The Omnivores Dilemma does a good job at explaining the USA's inability to come to terms with obesity and diet fads.
The most intriguing part was the point about gourmet meaning tradition. We don't have the tradition of other cultures and therefore we are at the mercy of "specialists" who come out with new fads every couple of years.
These diet plans are cash cows because of our life styles. I work with people who sit down to have a meal with their family once a year, if that.
Real food, cooked well, eaten in moderation, in a relaxed setting, with loved ones is all one needs. How novel is that?