In this land of growing girth where 66 percent of adults are now overweight or obese, some people have managed to stay at a healthy weight. Are they depriving themselves by eating tiny portions and giving up their favorite foods? You’ll be pleased to hear that the answer is no.
How do they do it? One trick is to learn which foods will fill you up without a lot of calories.
We study this in my lab at Penn State. In one type of study, we bring people into our laboratory, offer them various types of foods and see which ones fill them up the most. We conduct long-term trials to find out whether different types of dietary advice can actually help people lose weight and maintain that loss. We also analyze information from large surveys of what Americans eat.
Each of these different approaches has led us to the same conclusion: If most of your food choices pack lots of calories into each bite — we call these foods “calorie-dense” — you will overeat and get too many calories. Calorie-dense foods — for example, chips, cookies, pretzels and crackers — tend to be low in moisture and some also may be high in fat.
So how can you eat more and weigh less?
Choose soups, vegetables
Surprisingly, the component of foods that has the biggest impact on how much food you eat is water. Water adds weight and volume to foods without adding calories — it lowers the calorie density of foods. Water-rich foods include vegetables, fruits and soups. Our studies show that eating a diet low in calorie density helps people eat fewer calories while still eating a satisfying amount of food.
Several of our studies have looked at the best ways to include low-calorie-dense foods in a meal. We found, for example, that eating a 100-calorie bowl of broth-based soup or a green salad at the start of a meal takes the edge off your hunger. Even with the extra course of soup or salad, you are likely to eat fewer total calories during the meal.
Another effective approach is to add vegetables to your favorite mixed dishes — bulk up chili, stews and even macaroni and cheese with water-rich veggies like broccoli, carrots or tomatoes. Our studies show that you are likely to eat the same portion of food as usual and will be satisfied with fewer calories because some of the space in the bowl is taken up by low-calorie-dense vegetables. People tend to dish out the same portion, so why not make it lower in calories?
Eat for nutrition, as well as weight
A low-density meal is the ultimate value meal, one that gives you fewer calories and more nutrients in satisfying portions.
An analysis of what 7,356 U.S. adults reported eating, published in the American Journal of Clinical Nutrition earlier this year, showed that those eating a diet low in calorie density — rich in vegetables, fruits and other high-water foods — ate fewer calories per day (425 less for men, 275 less for women). And by choosing these foods, they were able to eat bigger portions without breaking the calorie bank.
What's more, this type of eating pattern supplies more of important nutrients such as calcium, iron, potassium and vitamins A, C, B-6 and folate, as reported in the August issue of the Journal of the American Dietetic Association.
Make small changes
We looked at the same survey data to help answer our question: What are normal-weight people eating? According to Dr. Jenny Ledikwe, a post-doctoral fellow at Penn State and lead author of the study, normal-weight people had diets lower in calorie density than those of their obese peers.
They are not depriving themselves; they eat a variety of foods from all food groups. She encourages people to “make small changes to their diet by incorporating additional fruits and vegetables to lower the calorie density. Lean meats, low-fat dairy products and whole grains are also good choices.”
To stay lean in this expanding world you don’t have to cut out whole categories of foods or eat tiny portions. These tips can help you choose a healthy balance of foods to lower the calorie density of your diet:
• Sneak vegetables and fruit into your diet throughout the day: top cereal with berries, snack on an apple or carrot sticks, tuck your favorite veggies into sandwiches or casseroles, increase the proportion of veggies on your plate.
• Cut the fat in foods without sacrificing taste by using a smaller amount of highly flavored vegetable oils, switching to lower fat milk and buying lean cuts of meat. Fat packs more than twice as many calories into an ounce of food as carbohydrates or protein.
• Keep your pantry well-stocked with a variety of your favorite low-calorie-dense foods so these are what you eat when you have the munchies.
• Focus on what you can eat, rather than what you can’t. Find a low-calorie-dense eating pattern that you enjoy so you will stick to it.
• Find ways to tweak your own diet using foods that you like and find appealing.
Barbara Rolls is the author of "The Volumetrics Eating Plan," which offers tips on how to lower the calorie density of recipes.