More Food, Fewer Calories?

Energy density is the key to healthy, high-volume eating

By Kathleen Zelman, MPH, RD, LD
WebMD Weight Loss Clinic - Expert Column

How would you like to eat more food and feel fuller, yet take in fewer calories?

Here's the secret: Choose foods that are low in energy density.

It may sound like weird science, but "energy density" is nothing more than the calories in a portion of food. Fruits, vegetables, legumes, and cooked grains are examples of low-energy-density foods that give you plenty of water and fiber for very few calories.

(High-density foods are the other side of the coin. These high-calorie foods tend to have less water and more fat -- which has twice as many calories as either carbohydrates or protein.)

Choosing foods that are high in water and fiber and low in density allows dieters to enjoy larger, more satisfying portions, and to lose weight without feeling hungry. For example, consider grapes vs. raisins: 100 calories of grapes is about two cups, but for the same number of calories, you only get 1/4 cup of raisins. It makes sense that two cups of grapes would be more satisfying than a few tablespoons of raisins.

How It Works

Barbara Rolls, PhD, author of Volumetrics Weight Control and professor at Pennsylvania State University, has done many studies on the concept of energy density. In a study published in the November issue of Journal of the American Dietetic Association, Rolls and colleagues found that study participants who ate a large (3-cup), low-density salad before a meal felt more satisfied and ate less total food during the meal. Those who ate a small, high-density salad with high-fat ingredients actually ate 8% more at the same meal.

Rolls suggests that having a large portion of low-energy-dense foods, like soup or salad, before meals is an effective strategy for weight control. A vegetable-based soup or salad as a first course increases fullness for very few calories, and thus can reduce your calorie intake for the entire meal.

Pump Up the Volume

You can lose weight simply by replacing high-density foods with high-volume, low-density foods like fruits and vegetables, according to a study Rolls presented last week at a meeting of the North American Society for the Study of Obesity in Las Vegas.

In the study, young women who replaced high-calorie foods with low-energy-density foods ate 800 fewer calories a day and never missed them, even with a 25% reduction in overall portion size.

We are all creatures of habit, and most of us tend to eat roughly the same volume of food each day. Here are a few easy ways to keep the volume in your diet while lowering the density (and calories):

  • Choose whole-grain breads.
  • Add veggies to soups, stews, egg dishes, and pizza.
  • Mix fruit into salads.

Not only will eating more of these kinds of foods allow you to feel full on fewer calories, they also happen to be supernutritious!

Water Weight

The water in food is one of the ingredients that help you feel full. Fiber is another, lowering energy density by providing bulk.

Foods that have plenty of both fiber and water (fruits, vegetables, cooked cereals, brown rice) have the greatest impact on fullness. If you drink a glass of water before a meal, it will not seem as satisfying as the same amount of water incorporated into food such as soup. When combined with low-energy-density foods, water dilutes the calories and has a longer-lasting impact on satiety.

Satiety

I call it the secret sauce in weight control. Satiety is the satisfying feeling at the end of a meal that signals you have eaten enough.

Have you ever been on a diet that does not provide enough food and, as a result, you get so hungry you deviate from the plan? It happens all too often, and is the main reason diets fail.

Eating just enough food to satisfy your belly and brain is no simple task; we all sometimes overeat because food tastes so good, even when we're already full. But eating satisfying portions of low-density foods can make it a bit easier.

Whole Grains

Researchers from Harvard School of Public Health who have followed 27,000 men for the past eight years have observed that those who eat plenty of whole grains tend to weigh less.

Whole grains contain more fiber than refined grains, and have a slightly lower energy density. Eating more whole grains should allow you to be satisfied with fewer calories.

The Take-Home Message

Of course, along with produce and whole grains, lean sources of protein and healthy fats are essential to a well-balanced diet. They also contribute to satiety.

The American Cancer Society advocates 5-9 servings per day of fruits and vegetables for good health. It really is a no-brainer: eat plenty of fruits and vegetables, and choose whole-grain carbohydrates and lean dairy and protein to help protect your health, increase satiety, and aid weight loss.

If you're a vegetable-hater, slowly incorporate more veggies into your eating plan -- and before long you will be meeting the national guideline.

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