P90X Diet: What You Need to Know

The P90X Diet has three phases, which roughly correlate to three phases of the P90X exercise program. The dieter can choose to follow any phase at any time.

The first phase of the P90X Diet is called "Fat Shredder." This is a high-protein, low-calorie diet, which aims to strip fat while building muscle. Half of all caloric intake is protein, 30 percent is carbohydrates and 20 percent is fat.

The second phase of the P90X diet is called "Energy Booster." During this phase of the diet, protein intake is reduced and carbohydrate intake is increased. The purpose of this phase is to provide increased energy. Caloric intake is set at 40 percent protein, 40 percent carbohydrates and 20 percent fat.

The third phase of the P90X Diet is called "Endurance Maximizer." This is an "optional" phase of the diet, which features complex carbohydrates and reduced protein. This phase is intended to provide the body with the energy it needs to meet the demands of intense P90X workouts. In this phase, daily diet includes 20 percent protein, 60 percent carbohydrates and 20 percent fat.

Within each of the three phases of the diet are three levels: one, two and three. Dieters are instructed to calculate daily caloric burn (plus 600 estimated calories spent on daily P90X workouts) and resting metabolic rate. The first level (within any of the three diet phases) is intended if daily caloric expenditure is 1,800 to 2,399; the second level is used if daily caloric expenditure is 2,400 to 2,999; and the third level is used for all higher daily caloric expenditures. The P90X nutrition plan offers meal suggestions for each level and each stage of the diet.

You can either proceed with suggested recipes or approach meal preparation by counting portions of food types to maintain the proportion called for by any phase of the P90X Diet. There are a variety of supplements available from the marketers of the P90X Diet, such as P90X Peak Performance Protein Bars, meal-replacement shakes and whey protein bars.

That's how the P90X Diet works. But what are its drawbacks? That's what we'll discuss in the next section.

One major drawback to this diet is the cost. To receive in-depth information about the diet, you need to order the P90X workout package, which costs $120 for the 90-day program. This doesn't include the additional costs of the dietary supplements that are sold separately. A package of 12 protein bars costs almost $24 before shipping and handling fees [source: Beachbody].

Many of the dietary recommendations run contrary to those of respected organizations such as the American Heart Association and the Mayo Clinic. The P90X Diet is light on fruits and veggies, while the Mayo Clinic recommends unlimited servings [source: Mayo Clinic]. The AHA doesn't recommend high-protein diets due to health risks such as elevated ketone levels in the bloodstream.

Eliminating carbohydrates cuts water weight, one reason many low-carb diets offer quick results. Unfortunately, this weight is easily re-gained. The Mayo Clinic recommends a diet consisting of 45 to 65 percent carbohydrates, 10 to 35 percent protein, and 20 to 35 percent fat (consisting of good fats such as monounsaturated fats) [source: Mayo Clinic]. Two of the three phases of the P90X Diet prescribe carbohydrate intakes that do not meet the minimum levels of carbohydrates called for by the Mayo Clinic.

Additionally, the three phases of the diet vary quite a bit from one another, and if all three phases are incorporated during the 90-day program, the dieter will have changed their diet three times in as many months.

While there are recipes supplied by the makers of P90X, there aren't enough recipes to keep you interested for too long past the initial 90 days.

And what happens after 90 days? The designers of the P90X Diet don't have a clear suggestion for whether you should maintain one phase or the other, and some of this confusion results from the fact that the program itself is only designed to last 90 days. After that, people who've completed the program are encouraged to try other programs offered by the same company, many of which include specialized nutrition plans.

In addition to the roughly hour-long daily P90X workouts, maintaining the P90X Diet may be a pretty time-consuming pursuit for dieters. Not only will dieters track calorie intake and expenditure, but meal preparation must be in accordance with dietary guidelines that shift depending on the phase.

The P90X Diet isn't being presented by nutritionists or health care experts, but rather by a company that is bundling it together with a made-to-sell workout routine.

In the long run, it may be better to adopt a diet recommended by a reputable health care agency or not-for-profit organization.

Keep reading for lots more information about different diets.