Would you believe the world of nutrition has its own weight loss scientists?

One of the most highly regarded researchers into the health benefits of soup, a professor at both Pennsylvania State University and the University of Pennsylvania Medical School, is Dr. Barbara J. Rolls. Dr. Rolls is famous for her work on the “volumetrics” of successful dieting, studies of how filling your stomach with liquid foods keeps you from craving more calories.

Dr. Rolls explains how the new cabbage soup diet and other similar diets work (and, to be fair, it should be stated that Dr. Rolls did not create the diet plan that is described on this site) in terms of what she calls energy density. The less space in your stomach that is needed for a calorie of food, the denser the food is.

A cup of butter contains about 1600 calories. It is very energy-dense. A cup of cabbage soup is about 10 calories. It is very energy-light. Both foods take up the same amount of space in your stomach so they should give you the same sensation of fullness, but butter has 160 times as many calories as cabbage soup.

That is why it is easier to eat less calories if you eat moist foods rather than dry foods. Bread is more filling than chips. Soup is more filling than bread. If you eat bread instead of chips, you will feel fuller on fewer calories. If you eat soup instead of bread, you will feel fuller on fewer calories.

How much cabbage soup is enough? Although Dr. Rolls did not specifically test cabbage soup, she tested the volume of soup needed to make a difference on your appetite in clinical trials with over 10,000 volunteers. A cup (240 ml) of soup is enough to make a difference, although bowl containing two cups (480 ml) of soup is better.

The soup can be pieces of vegetables floating in broth, or it can be a puree of vegetables floating in broth, or it can be a mixture of smooth and fat burning vegetables. This means the best cabbage soup diet recipe can use big pieces of cabbage, little pieces of cabbage, or pureed cabbage. All three reduce calorie consumption from 20 to 26 per cent. And if you reduce your calorie consumption by 20 to 26 per cent without changing anything except starting your meals with soup, you will lose five pounds a week effortlessly. And you can keep on losing after the first week.

A good question about this principle is, if eating energy-light foods is such a good thing, why not just drink a lot of water with your meals? Dr. Rolls tested this idea, too.

What this scientist discovered was that the size of the particles reaching your stomach determined how long the food would stay in your stomach. If your stomach receives lots of fine particles in a lot of fluid, such as it gets from soup, it will keep the food longer to digest it thoroughly. If your stomach receives a lot of big particles floating in a lot of water, it will keep the big particles and let the water flow on through. The water you drink with a meal does not stay in your stomach long enough to decrease your appetite. It will, however, slake your thirst.

And what about exercise? There’s nothing wrong with exercise, and there are a lot of reasons to exercise, but losing weight is not usually one of them. The weight you gain from new muscle usually exceeds the weight you lose fat. The new cabbage soup diet, however, will help you lose fat and preserve muscle so your weight goes down without your muscles shrinking.