These five bowls of snacks — jellybeans, raisins, grapes, apple slices and cherry tomatoes — show the different ways 100 calories can look. Ben Fink/The Ultimate Volumetrics Diet by Barbara Rolls, Ph.D., 2012.
UNIVERSITY PARK — The ideal diet for weight loss would allow people to eat foods they enjoy, feel full on fewer calories and have satisfying, nutritionally balanced meals. To meet these goals, Dr. Barbara Rolls and her team at Penn State’s Department of Nutritional Sciences developed the Volumetrics Diet, which is based on scientific studies of adult eating behaviors.
Rolls is a Penn State professor and the director of the Laboratory for the Study of Human Ingestive Behavior. She is also the best-selling author of three books for the public about the Volumetrics Diet.
“People wanting to lose weight get into this magical thinking: ‘I need something easy and the media tells me it’s going to work with no effort.’ That undermines what I want to emphasize, which is long-term, sustainable approaches to healthy eating that people enjoy,” Rolls said.
According to Rolls, weight management and healthy eating should be the same thing. When people are eating fewer calories for weight management, it’s especially important to eat a good balance of nutrients because they are eating less of everything.
Her first book, “The Volumetrics Weight-Control Plan,”was one of the first to recommend eating more food that was lower in calorie density to feel full and lose weight. A leading national consumer publication selected her second book,“The Volumetrics Eating Plan,” as the best diet book in the country, and it was a #1 New York Times bestseller.
She said the third book, “The Ultimate Volumetrics Diet,”is her favorite. It contains a 12-week program to teach the diet’s basic principles and the scientific basis for the principles. The book provides 100+ recipes, plus exercise suggestions, helpful tips and strategies and a menu plan created with registered dietitian Mindy Hermann.
Each week’s lesson covers topics like calorie density, portion size, snacks, drinks, managing fat and sugar, creating satisfying meals, eating away from home, consuming protein and fiber to increase fullness and maintaining the new diet.
“There are a lot of swaps people can do,” Rolls said. “I don’t want people to have to give up their favorite foods. I show them how to modify their favorite foods to make them less calorie-dense by bulking them up with favorite veggies and fruits and taking out a bit of fat without affecting how good they taste. These are things people can do to get more satisfying portions that also improve the nutrients in their diets.”
She said that in the lab, they look at what leads people to overeat, and strategies to help people manage hunger and eat less. “We have done a number of studies around what we call the Big Three, which are the most robust properties of foods that drive overconsumption. These are not surprising.”
“Portion size — bigger portions lead to greater consumption,” Rolls continued. “The density of calories in food is also a big driver of consumption. The more calorie-dense foods are, the more calories people tend to eat because we tend to eat a similar weight or volume of food at a meal. … And the third one is the variety. If you’re offered a wide variety of foods, you’re going to eat more than if you have less variety.” She said the book contains strategies for managing these food properties.
The Ultimate Volumetrics Diet encourages consuming adequate protein and reducing unhealthy fats and foods high in calorie density. It teaches people to feel fuller by consuming more foods with higher water and fiber content and with lower calorie density, such as whole grains, legumes, vegetables and fruits.
In year-long weight loss studies, Rolls said people who were told not just what they shouldn’t eat but what they could eat more of (fruits, vegetables, soups), emphasizing the positive, did better than people who were told to eat less fat, which was a more restrictive message.
She said fruits and vegetables are key because they are low in calorie density and are mostly water. Water adds weight and volume but no calories. Choosing water-rich foods allows people to eat satisfying portions while managing calories.
Rolls said year-long trials have shown tat people who are obese or overweight do better with the Volumetrics approach. “We’ve shown it works but the problem is always, with any diet strategy, maintaining it and continuing to adhere to it. We’re surrounded by very tempting foods that are inexpensive and really tasty. And it’s what we’re used to. So, if you stick to Volumetrics and find it enjoyable, it should work in the long term. You can learn that you can still enjoy your favorite foods, but perhaps with more moderation.”
“No matter what, people need to eat healthy. This is my worry,” Rolls said. “There have been all kinds of different approaches — the intermittent fasting, for example, just eating for a few hours of the day, which can help keep people away from food. But when they are eating, they need to still emphasize a nutrient-rich, healthy diet. A lot of the fad diets emphasize how easy it is rather than how nutritious and healthy it’s going to be long term.”
She continued, “The big shortfall in our field in terms of understanding is the long-term maintenance, how you keep people eating the way you know they should and probably they know they should in this environment. Calorie-dense, nutrient-poor foods are inexpensive and they’re everywhere. And they taste good. People have been brought up on them.”
The Ultimate Volumetrics Diet principles include thinking positively about what you can eat, following sound nutritional advice, choosing foods that help control hunger, having a good balance of nutrients, including your favorite foods in the diet, sustaining the new eating and activity patterns and recognizing that eating fewer calories than you use is the only proven way to lose weight.