Have you ever noticed that after eating certain foods -- especially those that are low in fiber and high in sugar -- you tend to get hungry rather quickly, while other foods keep you full for a longer period of time? Australian researcher Dr. Susanne Holt noticed, and her research led her to develop the satiety index. You can read more about the study here, but what it boils down to is that some foods keep you fuller longer than others.

Foods that are high in volume, fiber, and protein tend to stick with you and reduce your appetite, even hours later. Foods that have the same number of calories, may be lower on the satiety index because they lack one of those three characteristics. It's interesting research, and I'm looking forward to her adding additional foods to the list. Until then, you can see some of the foods she tested and their satiety ranking in the gallery below.

White bread is the reference point, with a satiety of 100. Foods are either less filling than white bread (under 100) or more filling (over 100).