Rank the food items in descending order of their energy yield per 100 grams Carbohydrate – A, Fats – B, Alcohol – C
**Core Concept**
The question tests the understanding of the energy yield of different macronutrients. Carbohydrates, fats, and alcohol are the primary sources of energy in the human body. The energy yield of these macronutrients varies significantly, and it's essential to know the exact values to calculate the energy requirements of an individual.
**Why the Correct Answer is Right**
The energy yield of carbohydrates is approximately 4 kcal/g, fats is approximately 9 kcal/g, and alcohol is approximately 7 kcal/g. This is because carbohydrates are broken down into glucose, which is then converted into ATP through cellular respiration, releasing 4 kcal/mol. Fats, on the other hand, are broken down into fatty acids and glycerol, which are then converted into ATP, releasing 9 kcal/g. Alcohol is metabolized by the liver, releasing 7 kcal/g.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because carbohydrates have a lower energy yield compared to fats and alcohol.
**Option B:** Incorrect because fats have a higher energy yield compared to carbohydrates and alcohol.
**Option C:** Incorrect because alcohol has a lower energy yield compared to fats.
**Clinical Pearl / High-Yield Fact**
Remember the mnemonic "CFA" to recall the energy yield of carbohydrates, fats, and alcohol: Carbohydrates (4 kcal/g), Fats (9 kcal/g), Alcohol (7 kcal/g).
**Correct Answer: D. Carbohydrates – A, Alcohol – C, Fats – B**