Caloric (Energy) Density
Calories per gram of a food — a key idea in filling, lower-calorie eating.
Formula
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Example
150 kcal in 100 g ⇒ 1.5 kcal/g
How it works
Caloric (energy) density tells you how much usable energy a food provides for each gram of that food. It is found by dividing the total energy in kilocalories by the mass in grams, so the result has units of kcal/g. This works because it standardizes foods of different sizes, letting you compare how energy-packed they are on a weight basis rather than just by portion size.
When to use it
Use this formula when comparing foods for weight control, satiety, meal planning, or sports nutrition. It is especially useful for deciding whether a food gives a lot of energy in a small mass, or whether it is lower-energy and more filling per gram.
Worked example, step by step
A snack bar contains 210 kcal and has a mass of 60 g. D = E / m D = 210 kcal / 60 g D = 3.5 kcal/g So the caloric density of the snack bar is 3.5 kcal per gram.
Common mistakes to avoid
- Dividing grams by calories instead of calories by grams
- Using the serving size incorrectly when the energy value is for a different mass
- Forgetting that the answer should be in kcal/g, not just kcal
Did You Know?
Cucumber is about 0.15 kcal/g while olive oil is ~9 kcal/g — a 60-fold difference in energy density.
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