While carbohydrates supply immediate energy for the body, lipids — a class of macromolecule — provide long-term energy storage.

Where is energy stored in this macromolecule?

Glucose energy is stored as glycogen, with the majority of it in the muscle and liver. The liver uses its glycogen reserve as a way to keep blood-glucose levels within a narrow range between meal times. Some glucose is also used as building blocks of important macromolecules, such as RNA, DNA, and ATP.

Which type of macromolecule stores energy most efficiently?

Fats (lipids)

Fats are the primary long-term energy storage molecules of the body. Fats are very compact and light weight, so they are an efficient way to store excess energy.