Human metabolism is the integrated network of biochemical processes that occur within the human body. It encompasses the conversion of nutrients into energy, the synthesis and breakdown of biomolecules, and the elimination of waste. As a research concept and academic field, it investigates the complex molecular pathways, reaction kinetics, and regulatory mechanisms governing these transformations at cellular, tissue, and systemic levels. Key characteristics include its dynamic nature, intricate regulation by genetic, hormonal, and environmental factors, and its central role in maintaining cellular function and physiological homeostasis. Its significance lies in providing fundamental insights into human health, disease etiology (particularly metabolic disorders), nutrition, energy balance, and overall physiological function.