Knowledge about the positive and negative effects of various dietary patterns is increasing. Medical aspects of nutrition are also gaining importance. This work provides an overview of the different facets of nutritional medicine, from physiological foundations to therapeutic aspects, from malnutrition to the consequences of obesity. It offers a reliable basis and scientific foundation: fundamentals of nutritional physiology, nutritional medical diagnostics, description of various nutrient groups, nutrition in different life stages and situations, food science, food safety, and legal aspects. Clinical focus: presentation of nutrition-related diseases, nutritional therapy for disease-associated malnutrition, management of overweight, obesity, and metabolic diseases.