What term describes the process by which the body uses food nutrients to produce energy?

The correct term for the process by which the body uses food nutrients to produce energy is metabolism. Metabolism encompasses all biochemical reactions that occur within the body, including those that break down food to convert it into energy. This process includes two main components: catabolism, which refers to the breakdown of molecules to generate energy, and anabolism, which involves the synthesis of all compounds needed by the cells.

Digestion, while an essential part of metabolism, specifically refers to the mechanical and chemical processes that break down food in the digestive tract. Absorption is the subsequent step where the nutrients from digested food are taken up into the bloodstream. Circulation refers to the movement of blood throughout the body, delivering nutrients and oxygen while removing waste products. Each of these processes plays a role in overall metabolism, but the term that best encapsulates the utilization of food nutrients for energy production is indeed metabolism.