OBJECTIVES: Obesity interventions often focus on weight and Body Mass Index (BMI), overlooking changes in body composition. Glucagon-like peptide 1 (GLP-1) agonist and glucose-dependent insulinotropic polypeptide medications (GIP) have been increasingly used in obesity treatment; however, their effect on body composition is controversial. The purpose of this study was to analyze the differential effects of lifestyle modification with and without nutrition counseling and/or GLP-1 medications on body composition.
METHODS: Retrospective data from World Trade Center Health Program (WTCHP) patients who were prescribed GLP-1 medications and had documented body composition analyses was reviewed. Patients were categorized into four groups: GLP-1 with nutrition group, GLP-1 group, nutrition group, and control group. The measures included fat, muscle, and visceral fat. Baseline and one-year follow-up values were compared.
RESULTS: The GLP-1 group experienced the greatest mean muscle mass loss (7.01 lbs) and the relationship between GLP-1 usage and muscle mass loss was statistically significant (p = 0.013). Both the GLP-1 with nutrition group and the nutrition-only group experienced less muscle mass loss on average. Patients in the GLP-1 group achieved the greatest overall weight loss on average (16.83 lbs, SD =15.01). The GLP-1 with nutrition group showed the greatest mean loss in fat mass (-10.77 lbs, SD = 26.93), and the nutrition only group showed the greatest mean loss in visceral fat (1.35 points, SD = 2.98).
CONCLUSIONS: GLP-1 medication was independently and significantly related to muscle mass loss, and those who took GLP-1 medications without nutritional therapy had the greatest mean loss in muscle mass. Compared to those who used GLP-1 medications alone, those who coupled nutritional therapy with GLP-1 medications experienced smaller reductions in muscle mass while also experiencing reductions in fat mass on average. These findings highlight the importance of incorporating nutrition counseling and body composition monitoring into obesity treatment.
