I tried it last year the same time I was breastfeeding (big mistake). I was hungry the entire time and I was miserable. My milk production decreased due to decreased food intake, although that has nothing to do with the diet itself. I lost 5 lbs after those 3 days and I'm sure it was just water weight. I gained that back in less than 3 days plus more. Highly recommend against this diet.
"Don't look at how far you have to go, look back at how far you have come."
I've heard of it but never did it myself, however my mom has used it and it seemed to have worked really good for her the for the first 3 days I think she said but when she went back on it after the break she didn't lose any, then she breaked again and lost a little but not as much as the first time so it seems to me it might be a good way to kick off a diet.