This lecture focuses on the various ways that meal replacements have been incorporated into NIH clinical trials to enhance weight loss results, namely the Diabetes Prevention Program and the Look AHEAD trial. These trials have effectively implemented lifestyle interventions aimed at a 7% weight loss in people who are overweight or obese with either prediabetes or type 2 diabetes. The listener will then hear about 2 specific cases that describe the effective use of meal replacements in clinical practice for patients who have type 1 and type 2 diabetes.