This diet is all about losing weight without feeling hungry. It's based on the concept of "energy density," which means how concentrated the calories are in a portion of food. High energy-density foods provide a large number of calories in a small serving, while low energy-density foods provide a small number of calories in a large serving. Authors Barbara Rolls, Ph.D., a nutrition researcher at Pennsylvania State University, and journalist Robert Barnett maintain that if you eat mostly low energy-density foods, you can eat more, satisfy your hunger, and still lose weight.
For example, you can eat 3 chocolate chip cookies (53 calories each) or, for the same 160 calories, you can eat 11/2 bananas or 2 apples. The fruit will satisfy you more not just because you can eat more of it but because it's high in fiber. Fiber and water both fill you up, while water dilutes calories per portion. The higher the water content and/or the higher the fiber content, the lower the energy density of the food and the more volume the food has, which affects how full you feel. Keep fiber intake high, drink a lot of water, and eat a lot of foods high in water content and low in energy density and you will lose weight, promise the authors.
The principle behind the Volumetrics diet is simple: Eat more foods that have low caloric density and you'll be able to eat more, satisfy your hunger, and still cut back on calories. According to the authors' research, we all tend to eat the same average weight in food every day, no matter how many calories the food contains. The Volumetrics approach is to eat the same volume of food but lower the number of calories by eating foods that are higher in fiber and water. If you do, you'll consume fewer calories and lose weight without that empty feeling in your gut. Once you learn to think about the energy density of foods, you'll be surprised by how much food you can eat. Volumetrics' message: Eat more fruits, vegetables, whole grains, legumes, and beans, and eat less high-fat, low-nutrient junk foods.