CENTRE COUNTY, Pa. (WTAJ) — Food. We need it to survive. We consume it every day. Yet, sometimes food has the power to consume us.

“My mother died way too young with complications from obesity and so I’ve always had this idea that I’ve wanted to do something about that,” said Dr. Barbara Rolls, professor of Nutritional Sciences at Penn State University.

Dr. Rolls has been studying different facets of consumption for almost 50 years.

“At some point we found that people tend to eat a very consistent volume or weight of food over a day or two,” said Dr. Rolls. “Once you understand that that’s what people are doing… the density of calories in that portion becomes really important.”

That’s how her 25 year study of calorie density began and the Volumetrics Diet was born. Her first of three Volumetrics books came out in the year 2000 and the diet is recognized by U.S. News & World Report as one of the best diets to follow.

“It’s based on research here at Penn State and research from colleagues around the world. It’s evidence based, science based, and it’s meant to be a sustainable program that you can follow and enjoy,” said Dr. Rolls.

So, what is Volumetrics?

Dr. Rolls says it’s not so much a diet, but a way to choose satisfying, lower calorie foods, that you can eat in larger portions to feel fuller. All you have to do is manage your food’s energy density.

“It’s just the number of calories per bite of food you take, so if you pack a lot of calories into each bite, you get much smaller portions,” said Dr. Rolls. “If you choose foods that are low in calorie density… your fruits, vegetables, broth based soups… you get big portions for your calories.”

One of the simplest ways to follow Volumetrics is to include more water-rich foods on your plate.

“Water gives weight and volume to foods and has no calories at all. And it’s actually the biggest component of most of the foods we typically eat.”

She recommends beginning meals with these foods, such as a broth-based soup.

“We’ve done a number of studies where if you have soup at the start of a meal, you end up eating less at the next course and indeed less in the whole meal, it’s this ‘filling up first’ strategy.”

To feel fuller, skip the dehydrated options. For example, choose a grape over a raisin. A small handful of raisins is the caloric equivalent to a bowl of grapes… about 100 calories.

Foods like tomatoes can practically be unlimited, says Dr. Rolls.

“Good to bulk up, you know, just add them to your favorite sandwich. Take out a little bit of the meat, perhaps, and substitute your favorite veggies.”

She adds these meals can reflect your favorite flavors and pack a yummy punch.

“Add some herbs, some spices, some flavor to give a boost so you enjoy them.” 

The Volumetrics diet has been recognized worldwide and Dr. Rolls has received a number of honors, but she says she’s most proud of her mentorship award from the American Society for Nutrition Foundation because it shows how she connects with her students, research peers, and Volumetrics followers.