This textbook is a practical guide to the application of the philosophy and principles of Integrative and Functional Medical Nutrition Therapy (IFMNT) in the practice of medicine, and the key role nutrition plays in restoring and maintaining wellness. The textbook provides an overview of recent reviews and studies of physiological and biochemical contributions to IFMNT and address nutritional influences in human heath overall, including poor nutrition, genomics, environmental toxicant exposures, fractured human interactions, limited physical movement, stress, sleep deprivation, and other lifestyle factors. Ultimately, this textbook serves to help practitioners, healthcare systems, and policy makers better understand this different and novel approach to complex chronic disorders. It provides the reader with real world examples of applications of the underlying principles and practices of integrative/functional nutrition therapies and presents the most up-to-date intervention strategies and clinical tools to help the reader keep abreast of developments in this emerging specialty field. Many chapters include comprehensive coverage of the topic and clinical applications with supplementary learning features such as case studies, take-home messages, patient and practitioner handouts, algorithms, and suggested readings.