Dietary calories refer to the amount of energy that is provided by food and beverages. Calories are a measure of how much heat can be generated from food through metabolism, and they provide an estimate of how many calories are consumed when eating or drinking something. The number of dietary calories in a particular item depends on its composition, such as the types of macronutrients (carbohydrates, proteins, and fats) it contains, as well as other factors like cooking methods and serving sizes.