Think Water and Fiber
Another good example is grapes vs. raisins. Fill a cup with juicy, fresh grapes and snack away: the entire cup contains only 104 calories. But fill that same cup with raisins and step away from the table, because the cup of raisins contains 434 calories. Fresh fruit fills you up with fewer calories because it’s full of water and fiber, the magic formula for low energy density. Dried fruit, like the raisins, contains little water; it’s denser with calories (and, often, concentrated sugars).
Whole grains cooked in water also are low-density foods that satisfy us with fewer calories. Cooked oatmeal, brown rice and couscous are three popular grains that are considered low-density because they absorb water in the cooking. And getting our water by way of cooked whole grains (carbs! yes!) can be a lot more satisfying than merely drinking a glass with our meals.