What does the liver store for energy use?

The liver primarily stores glycogen for energy use. Glycogen is a polysaccharide that serves as a form of glucose storage in the body. When the body requires glucose for energy—such as during periods of fasting or increased physical activity—the liver can break down glycogen into glucose and release it into the bloodstream to maintain blood sugar levels. This process is crucial for ensuring a steady energy supply, particularly for vital organs like the brain.

While the liver does play a role in the metabolism and storage of fats and proteins, and it is involved in the processing of various minerals, glycogen is unique because it directly serves as a readily available energy source that can be mobilized quickly in response to the body's needs. This storage capability is essential for maintaining homeostasis and providing energy during times when immediate glucose intake is not possible.