UNIVERSITY PARK, Pa. — People hoping to get in shape and eat healthier this year may want to try Volumetrics, the diet plan that was ranked No. 1 among weight-loss diets for 2022 by U.S. News & World Report.

The plan, which emphasizes foods that are low in calorie density, was developed by Barbara Rolls, Helen A. Guthrie Chair in Nutrition at Penn State. Volumetrics has appeared on the list every year for the past 12 years.

Rolls, also the director of the Laboratory for the Study of Human Ingestive Behavior at Penn State, credits the plan’s science-backed approach for its continued popularity and success.

“Research has shown that most people have a set idea of how big portions should be at various meals, so if a diet’s message is just to ‘eat less,’ many people are going to end up being hungry,” Rolls said. “The good thing about Volumetrics is you can still have a full plate, just with fewer calories. You get your usual portions and you end up eating healthier.”

Volumetrics is based on years of Rolls’ research on human nutrition and eating behavior, including how people can reach high levels of satiety — feeling full — while also consuming foods that help them achieve and maintain a healthy weight.

Rolls says the key is to build your meals around foods that are low in calorie density — that is, foods that don’t have a lot of calories in each bite. These include foods like fruits and vegetables, broth-based soups and low-fat proteins.

“It's about the density of calories that are packed into the food you eat, so if you choose foods that are very dry or have a high fat content, those tend to pack a lot of calories into each bite,” Rolls said. “If you want to have a full plate and manage calories, including more water-rich foods such as favorite veggies and fruits is the key to giving you satisfying portions. Herbs and spices are a great way to customize and add flavor to meals without increasing the calorie density.”

Rolls has published three books on the diet: “Volumetrics: Feel Full on Fewer Calories” (also published under the title “The Volumetrics Weight-Control Plan”), “The Volumetrics Eating Plan,” and “The Ultimate Volumetrics Diet.”

For those interested in getting started on the Volumetrics diet, Rolls said "The Ultimate Volumetrics Diet," which includes a 12-week plan, is a good place to start.

“The books gives recipes and tips on how to tweak favorite foods so they’re lower in calorie density but still tasty,” Rolls said. “Taking the time to cook your own foods allows you to be in control of each dish.”

According to Rolls’ research, water-rich foods such as soups fill people up while managing calories and promoting weight loss. For an example of what eating on the plan looks like, see the recipe below for Chicken Tortilla Soup. The heat level is customizable — add spicier salsa, a jalapeno or extra spices if desired — and can also be made vegetarian. The recipe makes four servings at two cups each.

Recipe for Chicken Tortilla Soup

• One tablespoon (14g) olive oil
• One medium (145g) onion, peeled and finely chopped
• Two medium (238g) red bell peppers, seeded and finely chopped
• One garlic clove (3g), peeled and finely chopped
• One cup (264g) mild or medium salsa
• Two 14.5 ounce (822g) cans reduced-sodium chicken broth (or vegetable broth)
• One 14.5 ounce (411g) can plain or seasoned fire-roasted diced tomatoes
• Two cups (280g) diced cooked chicken breast (or one 16 oz can of drained black beans)
• One cup (130g) fresh or frozen corn kernels
• One tablespoon (8g) chili powder
• Salt and freshly ground black pepper to taste
• Juice of ½ lime (22g) (optional)
• Garnishes can include ½ cup (122g) nonfat plain yogurt or fat-free sour cream, one ounce (28g) baked tortilla chips (about 18) crumbled, four sprigs (8g) fresh cilantro
   

1. Heat the oil in a medium pot over medium heat. Add the onion, red pepper and garlic, and cook, stirring occasionally, for five minutes, or until soft. Add the salsa, broth, tomatoes, chicken, corn and chili powder. Bring to a boil, then reduce the heat and simmer the soup partially covered for 15 minutes. 
2. Add the salt and pepper to taste and lime juice if desired. 
3. Ladle into bowls and garnish each with two tablespoons each of yogurt and tortilla chip crumbles, and one sprig cilantro.

This year, Volumetrics was also ranked No. 5 for best overall diet, No. 5 for best diet for eating healthy, No.7 for easiest diet to follow, No. 7 for best fast weight loss diet, and No. 8 for best diet for diabetes.