Insanity Work out.

I was thinking about doing it , i'm going to quit smoking and start doing it.
here is a great video . i did it for 5 mins and its whipping me pretty good . but 45 mins a day and 2 months loose 20 - 80 pounds why the hell not doing it . ima just keep practicing watching this video

Insanity 20 min Workout - Fat Burner - YouTube

So are you having any luck with it? How hard is it? Are you seeing results?