My Facebook is currently awash with the South Beach diet. Were my life to flash before my eyes, I'm sure there would be a surprisingly high amount spent listening to other people talk about diets.
It's shit. Self denial, foods being "naughty", eating being "bad", encouraging women to hate their bodies, crap science and it all seems to be more popular then ever and it fuels a billion pound industry.
And I think it's a massive example of the patriarchy at work and generally encouraging women to feel like lesser beings.