Question

The energy change produced by the combustion of food is called the 'calorific value'. The highest calorific value is given by
A. Proteins
B. Fats
C. Carbohydrates
D. Vitamins

Answer 1

Hint: To answer this question we have to know about energy sources in the metabolic process. Carbohydrates, protein, and lipids are the energy source in our body but fat gives the maximum energy in the metabolic process of our body.

Complete Step by Step Solution:
Fat is a nonpolar substance. It is composed primarily of hydrocarbons. It can be both hydrophobic and lipophilic. Fats are usually flammable and surface active substances. Most of the fats are unsaturated lipids that are present as a solid at room temperature. Both fat and oil are made of glycerol. Fat stores the food and energy of our body. On oxidation one gram of fat gives approximately \[37KJ\] of energy which is much higher than energy produced by carbohydrates.

Protein is a naturally occurring and extremely complex substance that consists of amino acid residues. Proteins are present in all living organisms. Protein is the most important essential constituent of diet because protein is the main food for bodybuilding. Proteins do most of the work in cells and they are required for the function, structure, and regulation of the tissues and organs of the body.

Carbohydrate is a compound of carbon, hydrogen and oxygen. It is an essential constituent of body but not an important essential constituent of diet as it helps in gaining weight. Carbohydrate is present in beans, milk, vegetables etc. It supplies energy to our body.
Vitamins are the essential constituent of our body. It functions in many essential works of our body.
Thus the correct option is B.

Note: On reduction lipid breaks into fat. Fat acts as the energy bank in our body. Fat is solid lipid. It is generally present below the dermis of our skin as subcutaneous fats.