Studies suggest that people eat the same volume of food day-to-day, regardless of the type of food eaten. So when we try improve our nutrition by reducing portions, we feel deprived and unsatisfied and are likely to return to our old eating habits. But it is possible to eat better without eating any less. The key is to increase your intake of low energy density food--foods that contain fewer calories per gram. In some ways this information isn't new--we all know vegetables are more nutritious than cookies. But by looking at low calorie foods as an opportunity to indulge rather than restrict, we may be more successful at incorporating them into our diets.
What makes food low in energy density. Foods that are low in energy density are high in other, low calorie components including water and fiber. The foods lowest in energy density include non-starchy fruits and vegetables and broth-based soups. Examples of these items include cucumbers, radishes, carrots, leafy vegetables, Brussels sprouts, zucchini, broccoli, cauliflower, peppers, apples, peaches, melons and berries. While these items alone do not make a balanced diet, they are great options for snacking or quelling a voracious appetite.
To determine the energy density in food items, divide the number of calories by the volume in grams to determine the calories/gram. Then you can compare this figure across food items to determine the lower energy density option.
Get more for less. The most obvious benefit of foods low in energy density is that, for the same amount of calories, you can consume a much greater quantity than a food higher in energy density. For example, if you're looking for a vehicle for hummus, for 100 calories, you can have 25 baby carrots or just 3 pretzel rods. Or opt for 100 calories of a salty snacky 3 cups of air-popped popcorn. This greater volume is useful for trying to change a diet because it allows you to eat better without eating less.
But greater volume is not the only benefit of volume eating. Because of their composition, many low energy density foods are going to be more filling than most of their higher calorie counterparts. This is because low-calorie foods tend to have more fiber which take longer to digest and help you feel fuller longer. In addition, fruits and vegetables are full of micronutrients like vitamins and minerals absent in many energy dense foods (such as white grains and sweets) that promote wellbeing. Volume eating can therefore be useful not only for calorie reduction but also a means to boost overall nutrition.
How to eat for volume. The key to volume eating is to swap out high energy dense foods in favor of foods with fewer calories and more micronutrients.
Take your favorite dishes and add more vegetables in place of some of the higher energy density components of the dish. I find this easiest to do with stir-fry and (whole wheat or chickpea) pasta. You can keep protein and carbohydrate portions smaller by filling the rest of the place with veggies that absorb sauce and flavors just as well.
Swap out your current snacks for lower energy density options without cutting the snack altogether. Consider vegetables in place of chips or crackers with dip, or naturally sweet fruits in lieu of post-dinner sweets.
As a general rule, look for foods filled with water and cut down on very dry options (e.g., cookies, crackers, nuts, seeds).
Start a high energy density meal with a low energy density appetizer, like a leafy green salad or broth-based soup. (But if you still polish off the dinner plate, then this technique might not be for you.)