A friend of mind did it, lost a lot of weight very quickly, but had no energy other than after her injections. Eventually her hair started to fall out as well.
It's a no-carb program. You live on salads, a bit of meat, and injections. Gradually, after the initial weight loss, they start to add more of a variety of foods back in to your diet. But it seemed to me on observing my friend, that if the nutritional needs were well balanced, than her hair wouldn't have been falling out. Overall she had a rather sickly look as well from losing the weight too quickly.
If you want a professional program, go with something like Weight Watchers. You won't lose more than about 2 pounds a week, but that is all anyone should be losing if they are doing it in a healthy way.