The Promise

Open the best-selling Body for Life book, and you'll see before-and-after photos of people who went from flab to fab. Give the diet 12 weeks, and you'll have your best body ever, too, the founder promises. But you're going to work hard for it -- with intense exercise nearly every day.

You'll also have to get used to eating six small meals a day -- mostly lean protein and healthy carbs -- instead of three larger ones. According to the diet's founder, Bill Phillips, this schedule is meant to steady your blood sugar, boost your energy, and help you prevent binge eating caused by getting too hungry.

The premise of the diet is that you're more likely to stick to a diet and workout if you see fast results.

What You Can Eat and What You Can't

At every meal, you get a fist-sized serving each of protein and carbs. Overall, the diet breaks down to about 40% to 50% of each, with very little fat.

You can have bread, pasta, potatoes, lean meats, fruits, vegetables, and small amounts of certain fats. The diet requires that you eat at least two servings of vegetables and drink 10 glasses of water daily.

Once a week, you get a "free" day, when you can eat whatever you want.

Except on your free day, you can't have bacon, fatty cuts of beef, hot dogs, or deep-fried meats. You're not allowed sugary or processed foods like cookies, cake, candy, white rice, chips, and soda. Some fats -- such as butter, lard, mayonnaise, coconut oil, and full-fat dairy products -- also are off-limits.

Level of Effort: High

You may see some quick results following the Body for Life program.But if you don't want to commit to fitting six small meals into your day, it could be tough to follow. The intense workouts 6 days a week may also be too much for many people.

Limitations: Preparing more meals a day can take more planning, though they can include the program's shakes or nutrition bars twice a day. The diet is also higher in protein than what is typically recommended.

Cooking and shopping: The diet includes recipes, sample meal plans, and shopping lists.

Packaged foods or meals: The plan suggests but doesn't require powders, shakes, supplements, and nutrition bars sold on the Body for Life website.

In-person meetings: No.

Exercise: You work out six times a week: 45 minutes of targeted weight training --3 days -- and 20 minutes of high-intensity cardio -- 3 days.

Does It Allow for Dietary Restrictions or Preferences?

Vegetarians and vegans: Plant sources of protein, like beans, often include carbs. You need to make sure you stay within the plan's carb rules. This diet would be difficult for vegans to follow.

Low-fat diet: Theres very little fat in this diet, unless you fill up on fats on your free day.

What Else You Should Know

Cost: None beyond grocery shopping. The emphasis on meat, fish, and other costly proteins might add costs to your food budget. The optional protein powders, shakes, and nutrition bars can also add up.

Support: The Body for Life website includes online tools and forums with an active community.

Does It Work?

The Body for Life program combines two proven elements of weight loss: fewer calories in and more calories burned. If you follow it closely, you'll likely shed pounds and build muscle. But be careful not to overdo it on your free day.

Research hasnt shown that eating frequent, small meals boosts weight loss success -- though it may have other health advantages. And eating more often may lessen the feelings of hunger that can sabotage anyones good intentions.

Is It Good for Certain Conditions?

Taking off extra weight will help prevent and treat diabetes, high blood pressure, and heart disease, regardless of the diet you choose. But you'll need to watch your cholesterol and how much salt and fat you eat on this plan.

Also, this diet may contain more protein than you should eat if you have kidney or other health conditions, so check with your doctor or dietitian first to make sure this plan is right for you.

The Final Word

Portion control and avoiding empty calories can help you shed unwanted pounds. But the plans emphasis on protein and carbs while requiring only two servings of veggies a day may lead to a lack of certain vitamins, minerals, and fiber.

You may struggle with this plan if you have a hectic schedule, since it takes time to plan and cook your meals, as well as to fit in the exercise required.

The Body for Life Plan is an intense physical program. It may not be for you if you hate to exercise or have certain medical problems.

The plan is more geared to strength training and falls short of the amount of aerobic activity (150 minutes a week) recommended by the American Heart Association.

You may feel tired as you cut back on calories and up your exercise, so start slow and listen to your body. Check with your doctor first if you have any health issues or have been inactive.