Never used it & never read it, but I my boss & a co-worker were doing it where I used to work.
Perhaps there is something to be learned from their failure, so I'll post it.
First, they were super strict & said NOT to eat a carb without protein. (sorry, if I ate a whole can of tuna at 12:00 & am hungry at 2:00, I don't see a problem with having an apple then & nothing more!). They also didn't like eating so many times a day & couldn't make it last past about 3 weeks, so instead of eating 1 or 2 *less* meals per day - they dropped it altogether (probably common mentality).
They also got a bit fanatical - acting as if this was the ONLY way to exercise & eat. Of course, that probably doesn't have anything to do with the book - but we all know an open mind is a good thing & variety in training is also vital.
I guess my experience listening to them (after having endured their crap 6 mos prior when they did Atkins & told me carrots & wheat bread would make me fat) turned me off a bit.
p.s. My old boss is at the same weight now over a year later, & the female co-worker is even more obese - (but they dropped it, so I'm not saying it doesn't work) .