What functions are realized by the human body due to the cleavage products: a) proteins; b) fat; c) carbohydrates entering the body with food?

The human body builds proteins and fats characteristic of it due to the products of food breakdown. The oxidation of fats and carbohydrates is the source of energy necessary for its vital functions.
When substances are broken down, the human body performs the following functions:
1) building (proteins, fats, carbohydrates);
2) energy (fats, carbohydrates);
3) catalytic (proteins);
4) protective (proteins).