Why Do GLP-1 Drugs Stop Working, and What to Do About It?: Medscape

Anne L. Peters, MD, CDE, professor and clinical scholar, Keck School of Medicine of the University of Southern California, and director, agreed that in the simplest terms, a plateau occurs because “the body becomes more and more used to” the weight loss intervention.

However, when you lose weight, you lose both fat mass and lean body mass, and lean body mass is the metabolically active part of your body, explained Peters. “That’s what burns and basically makes up your basal metabolic rate.”