Calories from Protein

Protein provides a measurable amount of dietary energy, and nutrition labels use a standard conversion of 4 kilocalories for every gram of protein. This formula turns a protein mass in grams into the energy it contributes to a food or meal. It is useful because grams and calories are different kinds of quantities, so the conversion lets you compare protein’s energy contribution with that from fats and carbohydrates.

Use this when estimating the calorie contribution of protein in a recipe, meal plan, or nutrition label. It is also helpful in basic diet calculations where you want to separate protein calories from total calories.

• Using 4 kcal for total food calories instead of only protein calories
• Forgetting that the protein amount must be in grams
• Mixing up kilocalories (kcal) with calories and reporting the wrong unit