If you have not seen an infomercial for P90x then you have been living under a rock for the last year or two. Every day and night there are infomercials showing the transformation of normal people. This program has an exercise program and a nutrition guide with it.
The exercise portion of it is quite brutal, but very effective. I would say that most people could not finish the workouts for a few weeks because they are so hard. The P90x nutrition guide is actually very good and it gives you a few different options to follow. This makes it easier for the people who are following the program.
The P90x nutrition guide follows a three phase system like most popular diets. Each of the phases should last 30 days. The only variation is if you want to lose a little more body fat you can stay in phase one a little longer. The name of the three phases are fat shredder, energy booster and endurance maximizer. The diet coincides with the workout program.
During the first phase you are just getting used to the workouts and you will be eating fewer carbohydrates than the other phases. Then in the energy booster you will get more carbohydrates because you will be exerting more energy during the workouts. Then you will get even more during the endurance maximizer because you will be at peak intensity during the workouts.
Personally I think that the P90x nutrition guide is one of the best there is. I think it definitely works best when you couple it with an extreme workout program like the one P90x has. If you follow both of them you will be in the best shape of your life for sure.