Which macronutrient provides the most energy per gram?

Which macronutrient provides the most energy per gram?

• A. Carbohydrate 4 kcal/g
• B. Protein 4 kcal/g
• C. Fat 9 kcal/g
• D. Alcohol 7 kcal/g

Answer: (C)

Among the macronutrients, fat provides the most energy per gram. Fat yields about 9 kilocalories per gram, which is higher than carbohydrates and proteins at about 4 kcal/g each. Alcohol can give around 7 kcal/g, but it isn’t classified as a macronutrient for nutrition purposes, so it doesn’t change the fact that fat has the highest energy density. The reason fat carries more energy is that fatty acids are highly reduced carbon chains, and their oxidation through metabolic pathways releases a large amount of ATP per gram.

Among the macronutrients, fat provides the most energy per gram. Fat yields about 9 kilocalories per gram, which is higher than carbohydrates and proteins at about 4 kcal/g each. Alcohol can give around 7 kcal/g, but it isn’t classified as a macronutrient for nutrition purposes, so it doesn’t change the fact that fat has the highest energy density. The reason fat carries more energy is that fatty acids are highly reduced carbon chains, and their oxidation through metabolic pathways releases a large amount of ATP per gram.