There was a thread on here a while back between a bunch of people who were trying it. Of course you can lose weight...you're starving yourself for days on end.
I would never try it...there is just no way in my mind I can justify starving yourself and I think the 'health benefits' that are claimed to be associated with it are no more than a cover up...a way to try to 'justify' not eating.
I think of it this way: How would I feel hearing that a bunch of teenage girls were trying it...most parents would be shocked and worried about eating disorders and pitching a fit...why should it be different for adults?