Calorie density is a measure of the calorie content of food relative to its weight or volume. It is also called energy density and is usually measured as calories per 3.5 ounces (100 grams) of food.

One of the most pervasive weight loss rules states that a cumulative energy deficit of 3500 kcal is required to lose 1 pound of body weight, or equivalently 32.2 MJ kg −1. The origin of this rule can ...