Its a jolt for people that have plateau'd with their losses. Its quite regimented and you have to really work at it to see a loss.
It is only recommended at 2 weeks at a time and then you go back to eating the usual SW way.
It's very strict - you're given a food plan for the week and can't go over it, not even by an apple! The people at my club who've done it have always done well on it, but they're literally delirious with cravings for food by the end of the week!! From what i've heard and seen it's hard, but effective.