The Volumetrics Eating Plan, a new weight-loss trend sweeping the nation, is winning people over with its eat more agenda.

Unlike diets that revolve around depriving their followers, the Volumetrics eating plan doesn't hold you back when craving a certain type of food.

Its creator, nutritionist Barbara Rolls, PhD, argues that limiting your diet too severely won't work in the long run. You'll just wind up hungry and unhappy and go back to your old ways, according to WebMD.

It's all a matter of calorie intake, says the doctor.

By choosing foods that have fewer calories per bite, your portion size grows, but your overall calorie count decreases, Rolls, author of the new book The Ultimate Volumetrics Diet, told CNN. So you end up with a satisfying amount of food.

Rolls, a professor of nutritional sciences at the Pennsylvania State University, has spent the last 20 years studying the science of satiety -- that feeling of fullness at the end of a meal - and the affects that it has on hunger and obesity.

According to the Rolls's research, the amount of food that we take in has a greater effect on how full we feel than the number of calories in the food.

So when speaking in terms of the Volumetrics eating plan, the trick of it is to fill up on foods that aren't full of calories.

A guideline that makes the Volumetrics eating plan so popular with the general public is that that it doesn't ban food types, as many other diet plans do.

And while Rolls doesn't distinguish between good food and bad food, she does urge people to evaluate foods based on their energy density -- a concept that is crucial to the diet, according to Jason Martuscello, a research specialist in Exercise Science and Nutrition at The University of Tampa.

This eating plan revolves around the volume of food, that's where volumetrics came from, Martuscello told International Business Times.

The standard foods used to succeed on the Volumetrics plan include water-rich foods like brothy soups, fruits and vegetables, whole grains, low-fat dairy, lean meat, and fish. The latter not only help control hunger by filling you up, but they also do it on fewer calories.

On the other side of the spectrum -foods that don't work for this diet -- are foods that are high in fat and/or sugar. According to rolls, they're less filling, plus they have more calories per bite.

Based on the previous information, the trick is to limit the low-volume foods and eat mostly high-volume ones. In doing so, followers will be able to eat double -- sometimes triple -- your portions while simultaneously losing weight, Rolls told CNN.

In a study co-authored by Rolls and published in a 2011 issue of the American Journal of Clinical Nutrition, people who ate an entree made up of 25 percent  pureed vegetables -- in this case, squash and cauliflower were blended into macaroni and cheese -- consumed 360 fewer calories per volumize the dish, tricking your brain into thinking you're eating more when in fact you're eating less.

This simple recipe modification ups your vegetable intake and reduces calorie consumption at the same time, Rolls told CNN.

Rolls's books are packed with recipes that are advantageous to the diet plan. Included are recipes for foods that contain high amounts of water, such as soups, casseroles, stews, and fruit based desserts. The recipes also use a lot of tricks familiar to low-fat diet veterans: cutting the oil, butter, eggs, cream, and using skim milk, egg whites, yogurt, and applesauce instead.

The more I looked into Barbra Rolls and the Volumetrics eating plan, the more her research interested me, Martuscello said

It's a great idea because this eating plan doesn't focus on food reduction, but more on understanding the density of food. he added.

Rolls, with co-author Robert A. Barnett, started making her case for the diet plan in 2000 with The Volumetrics Weight-Control Plan. In 2005, Rolls followed up with The Volumetrics Eating Plan, which restates the basics of the diet and provides further recipes.

Barbara Rolls is no business woman -- she's an educator, Martuscello said. Her eating plan is based on research that she has educated herself with in order to know what works and what doesn't work. In order to be successful with Volumetrics, you need to understand the principles she's trying to convey. She's not trying to dictate what foods you eat and don't eat. She's trying to make you understand the concept of density in food.

According to Martuscello, the Volumetrics eating plan, along with a healthy exercise regimen, is a full proof way to get in the best shape of your life.

The volumetrics eating plan is backed by science, Martuscello said. She's done the research and now she's spreading the word.

Penn State Interview with Barbara Rolls