Well, let me put it this way...i consider myself a pretty fit person. I train 5 times a week, mixed weights and cardio and also do a lot of boxing.
I have run several half marathons and completed 2 full marathons. I'm by no means the fittest person, but do ok.
However, this is on another level altogether! My whole body feels like its been 12 rounds with mike tyson everyday!
The nutrition plan is very well done aswell and provides a structured plan for the 60 days eating. It is not a diet, you simply couldnt diet with this level of training, but obviously, high protein, medium carbs.
I'm only a week in so my experience with it is still in its infancy, but loving it so far. :-)