Overview

• A narrative review in the Journal of Clinical Endocrinology & Metabolism shows GLP-1 receptor agonists drive major fat loss without improving VO2max, the gold-standard measure of cardiorespiratory fitness.
• Fat-free mass decline accounts for 25–40% of total weight loss on GLP-1 therapies, with muscle comprising 40–50% of that reduction.
• Researchers warn that losing lean mass during GLP-1 treatment may elevate risks of cardiovascular disease, all-cause mortality and diminished quality of life.
• The American Diabetes Association advises screening for malnutrition and low muscle mass before initiating GLP-1 treatment and endorses adequate protein intake and regular exercise.
• Experts are calling for larger controlled trials of exercise interventions and the development of muscle-sparing adjunct medications to safeguard long-term functional health.