About three weeks ago, The Ultimate Volumetrics Diet, the third diet book co-written by Barbara Rolls, PhD, professor of nutritional sciences at Penn State University, to explain a successful eating strategy that naturally leads to weight loss she calls volumetrics, hit the shelves.

Read up on the book at the Amazon.com website, and you'll learn The Daily Beast has dubbed it the "most effective diet of 2012," The Washington Post has called it "honest and honestly motivating," and USA Today believes it's "backed by the best research." You'll also learn that the editors of Newsweek magazine do not regularly read the "Fitness Master."

Or maybe they just have failing memories.

Newsweek claimed "Volumetrics could be the most popular and effective diet you have never heard of" even though this column glowingly praised the original work published a dozen years ago as well as its follow-up published in 2007.

All kidding aside, this column will advocate any variation of the volumetrics plan because its founding principle not only makes absolute common sense but is also supported by science.

While you may have days where you feel you've pigged out and consumed a surplus of food, you really haven't. On those pig-out days what you have done is consumed a surplus of calories.

Surprisingly, the amount of food you eat each day when measured by weight remains remarkably constant. In one of Rolls' first experiments with women, for example, they all tended to eat just about 3 pounds of food per day.

Rolls discovered this by having her subjects eat what appeared to be similar meals on different days, but the meals were not really the same. The pasta salad, for example, had more pasta one day, but more vegetables the next.

Yet the total amount of food by weight that the women ate did not change. What did change on the days that the pasta salad contained more pasta was the number of calories the women ate.

On those days, caloric consumption increased by 30 percent.

That's because pasta weighs less than vegetables per calorie, primarily because vegetables contain far more water and fiber.

It was a slew of experiments like this one that led Rolls to her theory. Eat the same amount of food by weight that you're accustomed to but replace lighter-weight, higher-calorie foods with heavier-weight, lower-calorie ones, and you'll lose body weight without that typical famished feeling you get after the first few weeks of most diets.

Now's the time for full disclosure. I'm partial to Rolls' theory of volumetrics because I was suggesting a similar eating strategy before I knew of Rolls way back in the 1980s when I first started teaching fellow teachers about nutrition.

But I wasn't citing other scientific studies back then. All I was doing was relying on common sense.

Picture 13 typical potato chips. Generally, they weigh 1 ounce and contain about 150 calories. Think about how quickly you can eat them and how often you eat more like a full bag rather than the suggested 1-ounce serving size.

Now picture 3 and cups of typical air-popped popcorn. The amount would nearly fill a super-sized soda cup.

This amount also weighs 1 ounce, yet only amounts to 88 calories.

In other words, if you allocate 150 calories for your after-supper snack, you can have 13 typical potato chips or 5.5 cups of air-popped popcorn. Eat the second snack slowly, and you'll be popping popcorn in your mouth all night long, which makes it easier to keep from eating anything else.

Compare potato chips to a snacking vegetable like celery and the serving size is even more extreme. You would need to eat 33 ounces of celery to consume the same amount of calories as found in 1 ounce of typical potato chips.

It's foolish to ask which 150 calorie snack is going to fill you up, but here's something from Rolls' first book that you probably didn't know. It's more than just food that satisfies hunger.

The contractions of the stomach required to break the food into particle small enough to enter the intestines sends that signal to the brain, too. Furthermore, any large volume of food releases cholecystokinin, a hormone that makes you feel full.

By eating volumetric foods, you get both of these feelings of fullness in far fewer calories.

For instance, a breakfast of a bakery-sized bagel, 1 ounce of cream cheese, 1 ounce of strawberry preserves, and 12 ounces of orange juice totals a bit over 600 calories. But so does 4 slices of whole wheat toast, 4 ounces of no-sugar strawberry preserves, 12 ounces of green tea sweetened with stevia, 1 hard-boiled egg, 1 banana, and 2 oranges.

If the second option seems like an excessive amount of food for breakfast, you get the concept. Create meals of great weight whether through water or fiber or a combination of both and there's no way that you will ingest the same number of calories you'd eat of light, calorie-dense foods.

Rolls' most recent book on volumetrics contains 105 recipes as well as a strategy for those times when you have to eat out, so if the concept of eating more by weighing less intrigues you, you may want to check it out.