Phillips emphasizes portions, not calorie counts. This is a 12-week fitness plan in which you eat a high-protein diet and exercise regularly. You eat six meals a day, consisting of one portion of protein and one portion of carbohydrates with some vegetables thrown in at prescribed times. Once a week, you're allowed a "cheat" day to splurge on your favorite foods. Although Body for Life emphasizes low-fat foods, the diet doesn't consist of enough variety for a truly healthy diet to meet all of your nutritional needs. This program's success is based on testimonials and anecdotal evidence.

This diet is about drastically reducing the intake of dietary carbohydrates to force your body to burn your reserve of stored fat for energy. This results in losing pounds and inches while still eating protein and fat-laden foods. Meat, eggs, butter and most cheeses can be eaten without restriction on this diet. The American Heart Association (AHA) has published a position statement against high-protein diets because weight loss that occurs as a result of a high-protein/low-carbohydrate diet is likely to be mostly water weight. They also warn that because this diet actually may have you eating high-fat foods you may, therefore, increase your risk of heart disease, high-cholesterol, liver and kidney damage, some cancers, and osteoporosis.

The authors of this diet claim that sugar is toxic to the body, causing the body to release insulin and store excess sugar as body fat. This diet recommends cutting sugar in refined and processed forms from the diet. This includes: potatoes, white rice, corn, white bread beets, carrots and sugar honey, corn syrup and foods containing them. By eating more protein over time than the body needs, particularly if the source is primarily animal protein, "bad" cholesterol increases. Long-term effects of high-protein, high-fat intake may include kidney and liver damage, heart disease and cancer. Sugar Busters! validity is based on opinions, not proven facts, and is supported by testimonials and anecdotal claims.

In this diet, used by stars such as Jennifer Aniston, meals should contain carbohydrates, proteins and fats in the ratio of 40 percent, 30 percent, 30 percent, respectively. A sample meal may be 2 cups of pasta (carbohydrate), a 3-ounce piece of steak (protein), and a small handful of nuts or other fats to round out the meal. The typical zone diet contains less than 1,000 calories, which may result in an inability to meet vitamin and mineral needs for most people, although not as restricted as other high-protein, low-carbohydrate diets, The Zone diet has not been validated scientifically. There's no scientific reason for eating set combinations of foods at set times.