The science that interprets the interaction of nutrients and other substances found in food and their role in the health of an organism is known as nutrition. It also deals with the maintenance, growth, reproduction and disease in organisms with respect to nutrients. Some of the processes which are studied under nutrition are food intake, assimilation, biosynthesis, catabolism and excretion. Proper nutrition is essential to avoid deficiency-related diseases like anemia, blindness, scurvy, stillbirth, preterm birth and cretinism. Metabolism is a group of life-sustaining chemical reactions in organisms. It helps in the conversion of food to energy for running cellular processes. It also converts the food to building blocks for proteins, nucleic acids, lipids and carbohydrates. Proper nutrition is essential for metabolism since metabolic pathways depend upon nutrients which they breakdown to produce energy. This book is a compilation of chapters that discuss the most vital concepts in the fields of nutrition and metabolism. The topics covered herein deal with the core aspects of these areas. This book will provide comprehensive knowledge to the readers.