I just think it's all insanity, LOL.
No really, my brother and a group of friends did P90x over a year - i.e., stretching out the exercises due to limited time. His results were awesome, and now he's on P90x 2 and adhering to the dietary guidelines.
Me? I've got P90x. My older sons love it. I want to love it. I want to do it. But my motivation level is low, unfortunately. I need to do it for my health/heart's sake. I'm only 43.5, but am the heaviest I've ever been for my small frame.
Once I turned 40, my metabolism seemed to have shut off or dropped off massively over night and what was previously a lifestyle of eating and no worries became the exact opposite. My doc(s) confirmed that this is not uncommon (turning 40 and the changes kick in).