Hey Tinkerbell,
I have a friend who did it. She said in some ways it's good, because if you ever deviate from low calorie/low fat foods, it "punishes" you for it (meaning, you're on the loo for hours.) And she DID lose weight. BUT she quite quickly put all the weight back on. I think she found it quite an extreme way of doing things, to be honest. She hasn't gone back to it.