This book provides a comprehensive and structured exploration of the biochemical principles that govern food composition, nutrient metabolism, and human health. It is designed to bridge the gap between theoretical biochemistry and its practical application in nutrition science, food technology, and health promotion. The text covers the metabolism of macronutrients and micronutrients, enzymatic processes, digestion, absorption, and the biochemical basis of nutritional disorders and lifestyle diseases. Special attention is given to the role of food processing, immunity, and public health nutrition in understanding how diet shapes human physiology. The book is intended as a self-contained academic resource for undergraduate and postgraduate students in food science, nutrition, biochemistry, and allied health sciences.