I've just read (skimmed, really) The Shangrala Diet. It basically boils down to something that could easily be handed out on a postcard.
" Take one tablespoon unflavored oil and one tablespoon plain old sugar in a cup of hot water twice a day.
Do not eat or drink anything but plain water for an hour before and after. Eat anything you want but don't go overboard".
The author does manage to flesh that out into a twenty dollar book though. Simple, easy, worth a try, right? So the way it works, at least the way I think it works, is that it makes you pay attention to when and what you are eating. It curbs your eating patterns in that since you can't eat within an hour of taking the oil or the sugar water so everytime you toss a pistachio into your mouth or grab an apple you must start over. It's sad when you get so old you can see it coming. I'm doing it anyway because I'm willing to bet that it will work as well as anything else.