myself and my boyfriend totally changed our approach to food after reading the four hour body. After following it for the past 18 months (with a few slip ups here and there!) both lost 3 stones each. Lost the first 1.5 stone very early on, and the rest has come off since. One major thing we noticed was how much energy we both had after giving up the white carbs. We tend to have saturdays as our 'binge' day (though i dont like calling it that, makes it sound a bit icky), so anything we've wanted in the week (chocolate, crisps) we keep till then. Some of out friends have tried it, and some have found it very beneficial like us, and others have hated it, mainly because they didn't see results after 3 days.
His claims of loosing 9kg in 30 days are little embellished, if you look at the actual data in the back of the book, its almost all men who lost this in that time. With the women, it took a lot longer.
One thing i would say, people will not understand why you don't eat fruit on it. I've tried and consequently given up trying to explain it people. Most people just don't understand that fruit is full of sugar. it really doesn't matter that its 'natural' sugar. unless you burn it off after eating it, it will get turned into fat.
But we love it, like i said, our whole approach to eating and our daily diet is basically slow carbing, and its done us a world of good.