Two work buddies used p90x with good results. Honestly man check this book out. It's life-changing. Don't worry you can still have steak and ribs! :-) It's the Paleo diet that crossfit uses and bageland recommended above.
http://www.amazon.com/Paleo-Solution...5751634&sr=8-1
IMHO, CrossFit is a great workout, but the program may be dangerous unless you are already well versed in olympic weightlifting and are in decent shape. They make you take an intro class series, but honestly you are so ill-prepared for the WODs after that, and many noobs come away with injuries. That being said, every crossfit gym is different, but there are many ways to get good results w/o the risk. Some of the crossfit stuff is straight up unsafe unless you are a real athlete/military, etc. For example a work out recently consisted of 20 GHD sit-ups (which make you dizzy as all heck) and then 5 or 10 clean and jerk variants. 5 rounds of that for TIME, so as fast as you can. Not safe to be doing c&j in a hurry while dizzy. Best of luck!
full disclosure - one of said noobs is myself.