There was a programme on CBC last night called "Diet Confidential". It was mostly about how in the last few decades the diet book industry has grown tremendously. One quote the caught my attention went something like this "It is the only industry that flourishes because of it's failures."
Marketting was a huge target. They followed one author's less than successful attempt to get a book written (studies funded by the sugar growers council) which states that artificial sweeteners are making us fat.
There was quite a bit of history, reinforcing the view that there is nothing new under the dieting sun. The narrator stated once that you don't hear much about calories any more. I guffawed!
They progessed from the stringency of Atkins thru the more temporate South Beach to French Women and the conjecture seems to be that 'more balanced eating' is the next happening thing.