Tag: Carbohydrate utilization

Over 50% of the energy expended by the human body at rest comes from fat oxidation. This process is crucial for maintaining the body's basal functions and is the key answer to the question of what fuel source does the body use at rest. While carbohydrates and protein also play a role, their contribution is typically secondary during periods of low energy demand.

For endurance athletes, the primary energy system powering their performance is the aerobic system, which relies on a constant supply of oxygen. This metabolic pathway is essential for sustained efforts like a long-distance cycling tour, though the anaerobic systems also play important, albeit shorter, roles.