When you’re eating dried fruit, do you ever stop to think about how much food you would be consuming if the fruit were fresh? Take raisins, for example. A quarter-cup of raisins has the same number of calories as about two cups of grapes. The difference? The grapes contain water, making them low in “energy density”—and nearly eight times the volume of food as the raisins.
Energy density refers to the number of calories in a given amount of food. Related to weight loss, it means feeling full on fewer calories. High-fat foods have a high energy density, whereas fruits and vegetables have very low energy density. For example, eleven heads of lettuce contain the same amount of calories as one stick of butter. The lettuce fills you up because it contains more water and fiber than the butter, thus contributing to volume and weight.
“Stretching the stomach with bulk produces a feeling of satiety,” says David Levitsky, professor of nutrition and psychology at Cornell University. “If a person ate all they wanted from low energy density foods, they would consume fewer calories.”
A healthy-weight food pyramid, released by the Mayo Clinic in their book Mayo Clinic on Healthy Weight (Kensington, 2000), was designed to manage weight and improve health with the help of low energy density foods. At the bottom of the pyramid is an unlimited amount of fruits and vegetables. Healthy food choices within the five food groups are recommended, such as whole grains for carbohydrates (brown rice, whole-wheat pasta) and monounsaturated, heart-healthy fats (olive oil, avocados, nuts). Physical activity is at the center of the pyramid, encouraging long-term health.
“Healthy lifestyle choices don’t have to be drudgery,” says Donald Hensrud, associate professor of preventive medicine and nutrition at the Mayo Clinic and editor-in-chief of the book. “People can lose weight and improve their health in the process.” The weight pyramid emphasizes a lifestyle approach to losing weight as opposed to going on a diet, which generally means going off of a diet, he says.
Unlimited amounts of fruits and vegetables excludes dried fruits and fruit juices, which are high energy density foods and can easily contain “hidden” calories. Consider that a glass of orange juice contains the juice of about four oranges, but you probably wouldn’t eat that many, says Hensrud. One orange would probably fill you up as much as the glass of juice, if not more.
Whole foods are emphasized for that reason—processed foods often contain many hidden calories. Fat, sugar and processing usually equates to a lot of calories in a small volume, says Hensrud. The same goes for meat, whole milk and eggs—all energy-dense foods. Levitsky suggests eating composite meals, such as stir-fries or stews served over pasta or rice, to obtain the flavor of meat in smaller quantities. As far as nuts go, watch the amount you consume, but treat them as a source of good fats.
A typical lunch for Hensrud is a Greek salad, which he says is healthy, tasty, practical and easy to prepare. Cut up two tomatoes, a cucumber and a green pepper, and combine with fresh basil, oregano or any other herbs. Make a dressing of red wine vinegar and olive oil, and toss on the vegetables with a couple of olives and some feta cheese. Hensrud suggests pairing the salad with a whole grain baguette and some smoked salmon for a filling, low-calorie lunch.