Explanation

Food contains a number of basic elements such as carbohydrates, proteins, fats and alcohol. These elements all produce different quantities of energy when burnt. The amount of energy produced when one gram of any of these elements is burned is known as its calorific value . Food component Energy density kJ/g kcal/g Fat 37 9 Ethanol (drinking alcohol) 29 7 Proteins 17 4 Carbohydrates 17 4 Organic acids 13 3 Polyols (sugar alcohols, sweeteners) 10 2.4 Fiber 8 2