Resistance exercise preserves muscle mass and increases strength during weight loss driven by GLP-1 medications, according to a world-first study published on November 10, 2026, in Nature Medicine, according to Mirage News.
The Tirzepatide and Resistance Exercise study followed 120 obese or overweight adults aged 50 to 70 years over 40 weeks. All participants received tirzepatide. Half the group performed three weekly resistance training sessions.
The trained group dropped an average of 22.28kg, while the untrained group lost an average of 22.61kg. Fat mass reduction exceeded 17kg across both groups.
Individuals who lifted weights lost 25 per cent less lean tissue than those who did not exercise. Upper and lower body strength improved by 10 per cent in the resistance training group and declined by 10 per cent in the untrained group, according to Nature Medicine.
Winthrop Professor Danny Green from The University of Western Australia led the study. He stated that losing lean mass is an inevitable part of weight reduction by any method.
With GLP-1 medicines now widely used and reducing body weight by an average of 20-25 per cent, and more than that in many people, it’s crucial that we understand how best to achieve optimal body composition and health in the weight-reduced state.
Professor Danny Green, Lead investigator
Miami biologist Gary Brecka noted that lean tissue accounts for roughly a quarter to a third of weight lost during obesity treatments. He recommended six minutes of daily resistance exercise to protect those tissues.
But with GLP-1s, you have a double-edged sword. About 20% to 40% of the weight that you lose is what we call lean body mass.
Gary Brecka, Biologist and longevity expert in Miami, Florida
All you have to do is provide resistance for these tissues so that your body doesn’t begin to reabsorb them while you’re on this GLP-1 journey.
Gary Brecka, Biologist and longevity expert in Miami, Florida
Laureate Professor Clare Collins conducted a systematic review of studies assessing diets of about 50,000 adults on these peptides. Collins noted that reduced food intake can lead to insufficient micronutrient and protein consumption.
You’re also not going to get enough of these vitamins and minerals that have specific roles in things like healing wounds, keeping your hair and nails growing, producing energy throughout your body or helping [the] neurons in your brain fire up.
Professor Clare Collins, Nutrition and dietetics expert
Clinical Associate Professor Janet Franklin from the University of Sydney pointed out that small food volumes make adequate nutrition difficult.
But are we not seeing it because people are still eating enough … [or] because we’re not testing for it?
Professor Janet Franklin, Dietitian and University of Sydney Clinical Associate Professor
I think it’s a theoretical risk [but it’s] one that you need to be conscious of.
Professor Janet Franklin, Dietitian and University of Sydney Clinical Associate Professor
Dr Karen Spielman, chair of the RACGP’s Specific Interests Psychological Medicine group, said primary health providers must monitor patients carefully.
Rapid weight loss at any body-size or shape can be really scary and can precipitate medical conditions,
Dr Karen Spielman, Chair of the RACGP’s Specific Interests Psychological Medicine group
and may lead to psychological distress if not managed with appropriate professional support and clinical oversight.
Earlier coverage: Tirzepatide Users Benefit from Resistance Training in Weight Loss Study