You may also express energy as kilojoules (kJ), with one calorie or kcal equaling 4.18 kJ. Regulations require that food and beverage manufacturers display a nutrition facts label on their products.

Alcohol is calculated at 7 Kcal/g. (These numbers were originally determined by burning and then averaging.) Thus the label on an energy bar that contains 10 g of protein, 20 g of carbohydrate and ...