The Pritikin Principle (cont.)

He claims the concern is not calories but rather how dense they are in any given food. Fill up on foods that have relatively few calories per pound and you will lose the "excess body fat that threatens your health and longevity."

Choosing foods that are not "calorie dense," such as apples and oatmeal, promises to "give you the freedom to eat until you are full and never limit your portions or be hungry in order to lose weight." The higher the caloric density of any given food, the more likely it is to cause weight gain, because you will consume more calories to feel full than if you choose foods with a lower caloric density. A pound of broccoli, for instance, has only 130 calories (that's raw and unbuttered, of course) but a pound of chocolate chip cookies has 2,140 calories. You get the drift -- broccoli, good; chocolate chip cookies, bad.

The Pritikin Principle: What You Can Eat

Some foods have more calories packed in them, bite for bite and pound for pound, claims Pritikin. If we eat foods with fewer calories per pound, we can fill up on these foods and still have the kind of calorie deficit that we need to lose weight. Pritikin doesn't shy away from the basic principle that weight loss is achieved by eating fewer calories than you burn each day, which is refreshing, given the spate of current diet books that attempt to ignore that simple but unalterable axiom. The Pritikin Principle has more than 20 pages of charts listing the caloric density of all kinds of foods, from snacks to sausages, listing them in calories per pound to graphically demonstrate the striking calorie differences between low-density foods and high-density foods.

Not surprisingly, the more processed the food, the more likely they are packed full of calories. Corn, for instance, starts out at a somewhat reasonable 490 calories per pound. By the time it ends up in a tortilla chip at your favorite Mexican restaurant, it's skyrocketed to 2,450 calories per pound. However, eat it with guacamole, and the combination (avocado dip with the chips) drops the number to 1,450 calories per pound.

The plan is to eat food with a large volume of fiber and water to fill up your stomach -- vegetables, fruits, beans, and natural, unprocessed grains. These foods, he claims, "create tremendous feelings of fullness, or satiety, in your stomach." In addition to eating three meals a day, the program incorporates two "calorically light" snacks as well. While Pritikin doesn't have you counting calories, you do have to possess a basic understanding of how to calculate the "average caloric density of your meal," and then keep that average below a certain number.

Exercise is strongly recommended, and walking is his favorite. How much is just right to maintain weight loss? Based on observations of obese people who lost weight and kept it off, Pritikin suggests "All of us should use ... 30 miles a week as a goal." For the rest of us, however, he suggests one 30-minute walk a day. Going at a good clip, you might average 12 to 15 miles a week.