It’s no secret that efforts to lose weight by controlling calories often succumb to feelings of hunger and deprivation. That’s why many nutrition researchers have focused on figuring out what foods make us feel full and satisfied.

They’ve found that satiety, the pleasant feeling of fullness, is about much more than just loading up on calories. The more low-calorie, satiating foods you can find, the easier it will be to maintain a healthy weight.

Satiety Index

Australian researcher Susanna Holt developed the Satiety Index in 1995. She prepared 38 different foods in 240-calorie servings and asked test subjects how full they felt after eating them. The individuals were not allowed to eat anything for two hours after consuming the servings, but then were allowed to eat from a small buffet as researchers recorded how much they ate.

Using the data from the study, Holt ranked the 38 foods on an index. White bread was assigned a baseline score of 100, and other foods were ranked in comparison to that score.

Holt found that, in general, foods with more fiber, protein and water kept people satisfied longer. These were also foods that tended to have larger serving sizes for the same number of calories. So oranges had a relatively high score, yet orange juice scored relatively low.

The 240-calorie serving of potatoes was one of the largest servings in the test, and not surprisingly, potatoes scored high on the index.

Foods with large amounts of carbohydrates — particularly whole grains — and protein tended to keep the test subjects fuller longer. Products with high amounts of fat, however, were not as filling.

Holt also found some foods were initially filling but did not provide long-lasting satiety. Fruits in particular filled test subjects up early, but left them ravenous again before their two hours were up.

Volumetrics

But Holt’s method of deriving the ranking was time- and labor-intensive. She was able to test only 38 different foods in her first study. And while that gave consumers a general idea of what to eat, it certainly didn’t cover the entire spectrum of food choices.

Barbara Rolls, a professor of nutrition at Pennsylvania State University, would later develop the concept known as volumetrics. That approach, which later spawned a diet book by the same name, looked at calorie density, or how many calories per gram a given food contained. Her research looked at incorporating more low-density foods such as fruits and vegetables in recipes, in place of high-density products full of fat and sugar.

Foods that are high in water and low in fat provide fewer calories per bite, and it’s the number of bites that provides that sense of fullness.

“Volumetrics translates the science into practical advice for both healthy eating and weight management,” Rolls said. “Research from our lab at Penn State suggests simple strategies, such as eating soup or salad at the start of a meal, that help people to manage hunger and reduce calories.”

Fullness Factor

Ron Johnson, the founder of the NutritionData.com Web site, tried to take those approaches even further. Building on the work of Holt and Rolls, he came up with a formula, dubbed the Fullness Factor, that tries to predict how filling a food would be based on its nutrients.

The formula takes into account the number of calories, protein, fiber and fat per gram. And the final score was easily quantifiable from nutritional databases, eliminating the need for extensive testing with actual people.

“The primary purpose of the Fullness Factor is to predict the satiating effect of a food. In other words, it helps determine which foods are better at creating a feeling of stomach fullness,” Johnson wrote on his Web site describing the formula. “Making high Fullness Factor foods a bigger part of your diet is a natural way to avoid hunger while consuming less calories.”

But how well did the formula work? Johnson compared the Fullness Factor scores with Satiety Index scores for Holt’s 38 initial foods, and the two rankings matched up very closely — that is, with the exception of potatoes.

The researchers suggested that perhaps the test subjects might have been put off by the large serving size of potatoes in Holt’s study (particularly with no butter or sour cream) and that may have skewed results. Nonetheless, potatoes score high in each of the three rating systems.

Better choices

While the rating systems can give you a great idea of how filling a food can be, they’re not the final word on what you should eat. After all, eating nothing but potatoes might be filling, but it would not be a very healthy diet. The NutritionData.com researchers attempted to solve that problem by combining their Fullness Factor with a nutrition density score. On their Web site, you can check where the foods you eat land on a nutritional target map. Foods in the lower left-hand corner are less filling and less nutritious, while foods in the upper right corner represent the best combinations of satiety and nutrition (see Page F1 for example target map).

The researchers note, however, that the map doesn’t suggest you limit yourself to the upper right quadrant. Instead, they suggest using the grid to make better choices. Plug in a food you eat, and the site will suggest foods higher in nutrition or that will satisfy you with fewer calories. Keep moving up and to the right, and you’ll improve your diet.

Dietitians said there are also other practical ways to use what has been learned about satiety to control calorie intake.

“When you’re making healthy choices, foods that are rich in fiber and nutrition are certainly going to feel more satisfying with less,” said Eris Craven, a registered dietitian at Bend Memorial Clinic. “Making healthy choices usually means lower-calorie items so you’re going to consume less.”

And while she’s never seen it scientifically quantified, she does believe that when people wait a few minutes before going back for more food, they often find they’re not as hungry as they thought.

“When you wait a little bit, you tend to notice, ‘I don’t really need any more,’” she said. “That time can be helpful.”

She also advises clients to spread the same amount of calories over more frequent, smaller meals rather than three large ones.

“Meal frequency, to me, is the most important factor when you’re looking at portion-controlling your meal, because that eliminates the willpower game,” Craven said. “When you’re eating often, every three to four hours, you have more success in your ability to control your portions.”

And while it doesn’t happen quickly, over time, your body can adjust to a different volume of food.

“You can easily have your body accommodate supporting more calories than you need; therefore, you maintain a higher body weight than is healthy,” she said.

The same is true with calorie restriction. Over time, the body will get used to feeling full with less.

Fullness Factor

The Satiety Index

Foods with higher scores make you feel more full than foods with lower scores.

ButterPotato chipsGlucoseHoneySnickers barRaisinsIce creamPizzaSpaghettiMacaroni and cheeseLowfat yogurtBaked potatoOatmealSirloin steak, broiledChicken breast, roastedOrangesCarrotsBean sprouts0.51.21.31.41.51.61.82.12.22.52.52.533.23.33.53.84.6

Source: NutritionData.com

Foods with lower scores are less filling; foods with higher scores are more filling.

CroissantCakePeanutsIce creamWhite breadSpecial KFrench friesBananasBrown riceLentilsWhite riceCheeseEggsWhole-wheat breadGrapesBeefLing fishPotatoes, boiled47658496100116116118132133138146150157162176225323

Source: European Journal of Clinical Nutrition