I have a friend that did this diet and lost a pound a day for 5 weeks – 35 pounds total. He told me that it can only be done for several weeks at a time, then a few months before you can do it again. He said that he had almost no appetite on the 500 calorie a day diet. He said that he feels fine now.
I have been losing about 1.5 pounds a week on the “hunger feels good” diet (I made up that name). Just eat less and when you feel hungry know that it means a sense of accomplishment. After a while you will get used to – and like – the hunger.