Jill O'Nan used to eat just one meal a day. But, as the joke goes, that meal began in the morning and didn't end until she went to sleep at night. As a freelance writer, O'Nan had no set meal schedule. "If McDonald's delivered, I probably wouldn't have left my house," says O'Nan, 45, who has battled the bulge since she was a child.
With her supersize appetite, O'Nan's weight spiraled to 360 pounds. She tried dieting, but nothing worked. O'Nan did some research and stumbled across a little-known book called "Volumetrics" (harpercollins.com), which promised that she could manage her weight by choosing foods that the program calls "low in energy density," foods that make you feel satiated, or full, but that are also low in calories. She swapped her serving of fast-food fries for an even larger portion of boiled redskin potatoes in a garlic-dill sauce.
She rediscovered her pressure cooker and started to make homemade meals, including soups and chili seasoned with dark chocolate. In four years she shed an impressive 220 pounds. "I never thought I would be able to get to a healthy weight without feeling deprived, miserable and hungry," says O'Nan, who now wears a size 8.
Volumetrics may be the most popular diet you've never heard of. It doesn't have the zing of The Zone or the image of bronzed beauties from South Beach. But it's been gaining currency with nutritionists and dieters alike for its simplicity and the fact that it's backed by recent peer-reviewed studies at a time when other diet plans have been losing favor.
Fighting hunger is the goal of Volumetrics, developed by Barbara Rolls, a professor of nutritional sciences at the Pennsylvania State University. Rolls has researched everything from thirst to portion control. But it's her study of satiety that is giving her street cred with dieters like O'Nan.
What Rolls found is that feeling full is intrinsically linked to certain foods. The nutritional principle behind those foods is called energy density, or ED. It may sound counterintuitive, but foods low in energy density make you feel fuller. Think fruits, soups and vegetables, all of which have high water content, "the secret ingredient" to satiety, says Rolls. (But drinking water alone won't help you feel full; it will only quench your thirst.) Rolls's research shows that a person eats about the same volume, or weight, of food every day. The trick is to fill your plate with low-calorie foods that leave you satisfied.
The good news is that Rolls isn't into deprivation, wanting to morph us all into plant-munching vegans. "Sound nutrition and weight management is all about choices," she says.
Her research shows just how powerful those choices can be. In a one-year study of Volumetrics, 97 obese women were divided into two groups. One group was taught the principles of Volumetrics and ate low-ED foods. The second group was told to restrict portion sizes and reduce fat. Neither group had to count calories or fat grams. What Rolls discovered is that both groups reduced fat intake and lost weight. But the group of women who had the low-ED foods actually ate a greater quantity of food over a year, but lost more weight—about 20 pounds, compared with 15 pounds for the fat- and portion-reducing group. They also fell in line with the USDA's Food Guide Pyramid (mypyramid.gov) recommendations: five servings of fruits and veggies a day (5aday.gov).
That's what makes nutritionists go gaga for Volumetrics. At New York Presbyterian's Comprehensive Weight Control Program, Volumetrics principles are taught to dietitians and physicians, who, in turn, use these principles to prescribe diets to their patients. "Trying to get people to go on a diet when they are hungry is very difficult," says Dr. Louis Aronne, who heads the program. "Volumetrics allows people to feel a sense of satiety."
It's not that tough to figure out the energy density of foods. (In Europe, Canada and other parts of the world, energy density is listed on the food label.) Simply divide the calories in one serving by its weight in grams. For example, one serving of creamy peanut butter is 190 calories and 32 grams, giving an ED of 5.9. Rule of thumb: eat all you want of foods that wind up with an ED rating of below 1, which includes most fruits and veggies. Foods with ED ratings of 1 to 2, like pasta and low-fat, skinless meats, are also good. Foods with higher-ED ratings, like ice cream and fries, should be limited, but not abandoned, "especially if you enjoy them," says Rolls.
In her newest book ("The Volumetrics Eating Plan"; volumetricseatingplan.com), Rolls gives detailed recipes, developed in her lab, that increase the portion size but lower the ED of traditional faves like risotto (decrease butter and cheese and add more vegetables, and you can fill your plate) and coq au vin (use skinless chicken instead of dark meat, use Canadian bacon instead of regular, decrease oil and add veggies).
If you want to reduce your calories even more, eat a salad before dinner, according to Rolls's study published in the Journal of the American Dietetic Association in 2004. Folks who were served three cups of salad totaling 100 calories before their pasta lunch ate 12 percent fewer calories overall, compared with when they were served no salad. And don't forget soup: another study published in Obesity Research in 2005 showed that folks who snacked on soup twice a day over a one-year period lost 50 percent more weight than those who snacked on high-ED foods like pretzels.
If all this sounds too good to be true, remember, the program is just a few years old, and long-term studies have been small. And unlike many commercial weight-loss programs (Rolls is a medical adviser for Jenny Craig and has adapted a cookbook for the program), there is no support group for Volumetrics followers. Research shows that support is a factor for long-term success.
That's why some folks like Linda Gilpin of Pictou, Nova Scotia, who picked up Rolls's first book last year and managed to shed 50 pounds, seek help at the Internet site 3fatchicks.com. (Other good sources: diettalk.com, weightlossbuddy.com, weightcircles.com.) "I eat so well now, and I feel full, but anyone who has ever tried to lose weight and keep it off knows you need some kind of support," says Gilpin. "It helps to have somebody be on your side." And something on your plate, other than one carrot stick.