I think this diet is extremely dangerous. It restricts your calories below 800 with some people actually eating as few as 300 calories a day. This is an anorexic diet! Of course they lose fast and lots of weight. But if you lose more than 2 lbs a week, you are also losing muscle. Remember that your heart is a muscle and anorexics often die of heart attacks.

I think if you follow a low carb diet and keep the calories high enough to provide for normal body functions (10-12x your goal weight) you will succeed and be better off for it.