Five decades ago, the major nutrition-related issues facing the United States were nutrient deficiencies, under consumption of calories, and malnutrition. In 2016, however, the food landscape is drastically different, and today, the United States faces nutrition-related issues more closely associated with over consumption of calories, bigger waistlines, and chronic disease. Overweight and obesity now afflict the majority of U.S. adults and a large percentage of U.S. children. In addition, diet-related chronic diseases that used to be exclusively observed among adults (e.g., cardiovascular disease, type 2 diabetes mellitus, and hypertension) are now being detected in children and adolescents. To lower the risk and/or assist with the management of chronic illnesses, overweight and obese patients are frequently advised to lose weight. Although there are many proposed "quick fixes" for weight loss, long-term weight management is a struggle for most patients. As such, nutrition and healthcare clinicians need to understand the etiology of weight gain and the science-based steps necessary for proper and adequate weight management interventions. This textbook comprehensively examines the treatment of overweight and obesity using an individualized approach. Interventions including diet and behavioral modification, pharmacotherapy, surgery, and physical activity are discussed in the context of an overall lifestyle approach to weight management. Characteristics of successful weight management programs are explored, and example menu plans are provided.