This isn't a diet that I personally would follow, and I personally would not recommend it to my friends.
You are right about it being low cal and restrictive. You consume 800 calories per day. You eat six of their cookies, and then you get one piece of chicken or fish, with 1 cup of vegetables.
Anyone following a diet that low cal will lose weight, but studies have shown that quick weight loss is nearly impossible to maintain.
I'm also a bit insulted that people think that just because we are overweight that we would want to eat cookies all day.
If you do try it, please see your regular physician as well, not just the doctor at the clinic. It's important to get an unbiased view of the diet and how it affects your personal health along the way.
Good luck