I went on this in October and lost about 4 out of the 10 lbs I wanted.
But, what I learned from this diet, at least about how my body reacts to carboydrates, was invaluable.
Basically, the South Beach diet encourages low glycemic carbohydrates and prohibits sugar. The first couple of weeks you are to free to eat meat, low fat cheese, vegetables and limited portions of nuts. Then after two weeks you can add fruits and high fiber breads and cereals. After about a month, I noticed some of the ugly fat layer start disappearing. Especially in my abs.
I haven't kept a strict regimen of eating this way, but I have upped my protein and my good fats. I have added pistachio nuts as part of my daily diet, high in protein and contain good fat. I limit them to 1/4 cup per day because of the calorie content but they really fill me up. Even though I'm not following the diet to a T, I am still down the 4 lbs and each week I notice more definition.
In answer to your question, the book is very explicit on what are good carbs and good fats, so if that is your goal, I would recommend.
