Michael Monostra , 2025-04-18 13:06:00
April 18, 2025
2 min read
Key takeaways:
- Most of the weight lost by adults using an obesity medication came from fat mass.
- Researchers said careful monitoring of body composition is needed to protect muscle mass with obesity pharmacotherapy.
Editor’s note: Full data from this research will be presented at the European Congress on Obesity in May.
Adults with obesity who used medication and received guidance on resistance training and nutrition lost substantially more fat mass than muscle mass, researchers reported in data that will be presented at the European Congress on Obesity.
Data were derived from Peralta-Reich D, et al. Abstract 1604. To be presented at: European Congress on Obesity, May 11-14, 2025; Malaga, Spain.
Alexandra Filingeri
“While weight loss is a key goal in the treatment of overweight and obesity, preserving muscle mass is essential for long-term health, function and metabolism,” Alexandra Filingeri, DCN, RDN, a registered dietitian at New York Weight Wellness Center, and Dina Peralta-Reich, MD, founder and director of New York Weight Wellness Center and director of pediatric hospitalist medicine at Lenox Hill Hospital, Northwell Health in New York, told Healio. “Incretin-based medications reduce appetite and calorie intake, which can lead to muscle loss if not carefully managed. Monitoring body composition helps guide strategies that support fat loss while protecting lean mass.”
In a prospective cohort study, researchers enrolled 200 adults aged 18 to 65 years with overweight or obesity (mean age, 47 years; 50.5% women) using semaglutide (Wegovy, Novo Nordisk) or tirzepatide (Zepbound, Eli Lilly). Participants received education about GLP-1s, were encouraged to perform resistance training and increased protein intake during the study. An obesity physician supervised the participants. Body composition was measure at baseline, 3 months and 6 months using bioelectric impedance analysis.
Of the study group, 60% used tirzepatide and 40% used semaglutide.
Women achieved a weight loss of 12% during the study, with weight decreasing from 156 lb at baseline to 137 lb at 6 months (P < .001). Women lost an average of 24 lb of fat mass and 1.4 lb of muscle mass at 6 months.
Men lost a mean 13% of their body weight, from 223 lb at baseline to 193 lb at 6 months. Of the weight lost, about 25 lb consisted of fat mass and 2.4 lb was muscle mass.
Dina Peralta-Reich
Of the participants, 95% said they adhered to GLP-1 therapy at 3 months and 89% said they were adherent at 6 months. Participants who exercised regularly and had consistent protein intake were more likely to retain muscle mass, according to the study abstract.
Filingeri and Peralta-Reich said the findings revealed the importance of lifestyle intervention and obesity medicine specialist support during GLP-1 treatment.
“Clinicians should recognize that medication alone is not enough; guidance on nutrition and resistance training must be incorporated into care plans to preserve lean mass and support functional outcomes,” Filingeri and Peralta-Reich said.
Reference:
For more information:
Alexandra Filingeri, DCN, RDN, can be reached at alexandra@nutritionbydralexandra.org or on Instagram @Nutritionby_dralexandra.
Dina Peralta-Reich, MD, can be reached at drdina@nyweightwellness.com or on Instagram @drdinaperalta.
Sources/Disclosures
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Peralta-Reich D, et al. Abstract 1604. To be presented at: European Congress on Obesity, May 11-14, 2025; Malaga, Spain.
Disclosures:
The authors report no relevant financial disclosures.