What does the term "metabolism" describe?

Metabolism refers to all the chemical reactions that take place within the body to convert food into energy. This includes not only the breakdown of food into usable energy but also the process of building and repairing tissues, regulating chemical levels, and maintaining homeostasis. Metabolism is a comprehensive term that encompasses both catabolic reactions (breaking down molecules for energy) and anabolic reactions (building up molecules).

This understanding clarifies why the selected answer captures the full scope of metabolism beyond just exercise or specific types of macronutrient breakdown. While certain metabolic processes specifically affect fat burning or carbohydrate breakdown, metabolism as a whole involves a vast array of biochemical reactions critical for life's functions.