The prevalence of obesity continues to increase in many developed countries throughout the world and is now referred to as a pandemic. Obesity is a chronic, relapsing disease, with neurochemical changes that influence energy balance, often rendering traditional treatment interventions ineffective at restoring normal body weight. Therefore, obesity treatment interventions, including dietary strategies, are receiving increasing attention by investigators and clinicians. Hundreds of randomized, controlled trials examining various food diet interventions have found modest long-term weight loss. Meal replacements in the form of drinks, bars and entrees work to replace food, restrict caloric intake and blunt the rise of postprandial blood sugar, fatty acids and the resultant secretion of incretins, insulin and other factors. Thus, these agents have a significant neurohormonal impact that enables weight reduction and have therefore been referred to as nutraceuticals – nutrition with a pharmaceutical effect. There is accumulating evidence that meal-replacement dietary approaches are superior to all-food approaches for short- and long-term weight loss, as well as improvement of obesity comorbidities.