When it comes to losing excess weight, most people focus on how much they are eating, e.g. they watch portion sizes and count calories. Unfortunately, most people who restrict calories and lose some weight initially usually complain about increased hunger. When people are hungrier their commitment to eating less usually wanes over time and the weight is regained. Research suggests people could eat fewer calories and lose weight without having to fight chronic hunger if they focused on what they ate rather than on how much they ate.

The key to long term weight control may turn out to be focusing on eating foods that keep hunger at bay at a lower calorie cost.Calorie density, also known as energy density, is measure of the amount of calories in a given weight of food. For example, a pound of lettuce has 77 calories, making it much less calorie dense than chocolate at 2172 calories per pound.When people eat until they feel full and do not worry about measuring calorie intake this is called ad libitum or at-will eating. While some people think counting calories and portion control helps people eat fewer calories, the reality, according to most studies is that eating the right lower-calorie-dense foods ad libitum can dramatically cut calorie intake without leaving people hungrier. It is also much more pleasant and worry free to eat ad libitum than to always worry about counting calories.If people consume low-calorie-dense foods such as soups, salads, hot cereals, whole wheat pasta and fruit, versus cheeseburgers, French fries and pizza, they will feel full on far fewer calories.Short-term studies have consistently shown that the greatest predictor of ad libitum calorie intake is the calorie or energy density (ED) of the foods consumed.Other dietary factors, such as a higher percent of fat and/or a lower amount of fiber, in the diet have also been associated with a more modest increase in ad libitum energy intake. However, most, if not all, of the impact of these dietary variables on ad libitum energy intake is greatly attenuated when the ED is held constant despite a higher fat or lower fiber content of the diet. Simply put higher percent fat and lower fiber foods promote over eating largely because they are more ED and provide less satiety per calorie than vegetables, fruits, and other low ED foods.Some skeptics believe that ED does impact how many calories people eat in the short-term but they argue that over time the body would compensate and increase hunger sufficiently to increase the food intake enough to regain the weight despite a lower-calorie-dense diet.A recent study of the impact of ED on the BMI of men and women of several ethnic groups suggests that if such compensation does exist it is far from complete. Using food frequency questionnaires to access what people ate they found a highly significant positive correlation between the ED of their overall diet and their BMI. The authors conclude: ?Our findings suggest that consumption of an energy-dense diet is a risk factor for a higher BMI in both men and women across ethnic groups.?1 The authors noted that because of errors in the reported amount of food eaten that ??it is possible that ED is a better predictor of actual intake than energy intake alone.? In simple lay terms high ED foods are fattening because they require people to consume more calories or fight chronic hunger.High ED foods generally provide less satiety per calorie than low ED foods. As a result efforts to reduce calorie intake by limiting the portion size of high ED foods may be doomed to failure because people will get hungrier on a calorie restricted ED diet. Hungry people are strongly motivated to eat more not less. If the focus is switched from portion size and calorie content to consuming a low ED diet, growing research shows calorie intake can be reduced without having to battle increased hunger. Given the extremely poor long-term success rates of the traditional focus on limiting calorie intake by eating smaller portions of the high ED perhaps the time has come for health professionals to switch their focus instead to eating a diet consisting mostly low ED foods.By James J. Kenney, PhD, RD, FACN.References:1 J Nutr 2006;136:2243-8 Very Low in Calorie Density - the very best choices:Nonstarchy vegetables, strawberries, lowfat soups and skim milk.Low to Moderate in Calorie Density - also good choices:Fresh fruits (except bananas), nonfat yogurt, oatmeal, cream of wheat, grits, whole wheat pasta, potatoes, barley, whole grains cooked in water, beans, seafood, white meat poultry without the skin and lean meat.Medium - use caution and portion control:Fatty meats, fatty fish, bread, jam, french fries, pizza, cheesecake, apple pie, fatty processed? meats, hot dogs, some high-fiber cereals, avodaco.High or very high - severely limit or omit these items:Chips, muffins, cookies, pretzels, nuts, sugar, honey, cheese, pastries, chocolate, oil, mayonnaise, butter, nut butter, candy, crackers, candy, dry cereals, margarine, bacon.