I just did some research on it, and it reads like a typical diet plan - not necessarily a fad, but not something that you can sustain long term. And I don't think it really does anything teach you about healthy eating.
That's assuming that you're talking about this diet: .
The calories are waaaayyy too low to be a healthy or reasonable diet for anyone. No one should go under 1200 calories a day w/out a doctor's supervision. Most people should be eating around 10 calories per pound of body weight each day in order to lose weight. (As an example, I weigh 170, so I eat around 1600-1700 calories per day.)
Also the idea that you can fill up on fiber and lose weight is jut another trick method of caloric restriction. The problem is that for a lot of people, a very high carb diet causes bloating and fluid retention ... so that right there can offset a lot of fat loss.
I'm sure it will work while you're on it, if you stick to it. The question for me is, what happens when you lose the weight you want to lose and quit doing the diet? Is the plan sustainable?