Carbohydrates, lipids and proteins are classified as

Carbohydrates, together with lipids, proteins and nucleic acids, are one of the four major classes of biologically essential organic molecules found in all living organisms. They not only provide energy for vital metabolic reactions but also supply the building materials for normal structure, growth and repair. Your body needs relatively large quantities of carbohydrates, fats and protein for optimal function, hence their classification as macronutrients.