Question

Which food gives the most energy per gram?

• A. Protein
• B. Fat
• C. Carbohydrate
• D. Vitamin

Hint:

Compare how many kilocalories one gram of fat releases against one gram of carbohydrate or protein.

Answer 1

The Correct Option is B

Step 1: Know the three main energy-giving nutrients.
The body gets its calories mainly from carbohydrates, fats and proteins. Each of these breaks down inside the body to release energy, but they do not release the same amount of energy for the same weight.

Step 2: Compare the energy each nutrient releases per gram.
One gram of carbohydrate gives about 4 kilocalories. One gram of protein also gives about 4 kilocalories. One gram of fat gives about 9 kilocalories, more than double the other two. This is why fat is called the most energy dense nutrient.

Step 3: Rule out the other options.
Protein, at 4 kcal per gram, is mainly used to build and repair body tissues, not as the top energy source. Carbohydrate, also 4 kcal per gram, is the body's preferred quick fuel because it is broken down and used fast, but it gives less energy per gram than fat. Vitamins do not provide any calories at all, they only help other reactions in the body run smoothly.

Step 4: Confirm the answer.
Since the question asks for energy per gram, and fat yields the highest number of kilocalories for the same weight compared with carbohydrate, protein or vitamins, the correct answer is Fat.