Put simply, calorie density is how many calories there are in a given weight of food. Research will report it in grams, which freaks some people out. But it can also be expressed as calories per pound. There is a huge range of calorie density, and understanding and applying this can make a big difference in maintaining a healthy weight.
Why the Weight of Food Matters
The most important factors in feeling satisfied after eating are weight and volume of food. That’s what “fills you up”. The stretch receptors in the stomach are powerful indicators of whether or not you feel like you ate enough. If you trigger those stretch receptors with very calorically dense foods, you will likely overeat. But if you trigger those stretch receptors with calorically less dense foods, you can feel “stuffed,” but without overeating on calories. Water content (weight) and fiber content (bulk) are what matter most.
Which Foods Decrease Calorie Density?
Fruits, vegetables, whole grains, legumes, and starchy vegetables all contain lots of water and fiber to fill you up without overeating. Remember that whole grains and legumes are cooked in water, most of which is absorbed. But refining foods into flours, or adding sweeteners and oils dramatically increases the calorie density while doing very little to satisfy you.
But Doesn’t Fat and Protein Fill You Up?
In my experience, no. I can eat thousands of calories of pizza and feel the same as eating a few hundred calories of veggies. It is true that fat and protein can contribute to the “richness” of a food, but I find that weight and volume is far more satisfying.
Nutritionist and Registered Dietician Jeff Novick explaiing it better than I do: