GLP-1 Patients Are Moving Less, Not More : Here's Why That Matters

There's a common assumption about weight-loss medications like Ozempic, Wegovy, Mounjaro, and Zepbound: as the weight comes off, people naturally start moving more. Lighter body, easier to walk, easier to exercise, more energy. It seems intuitive.

A study presented this June at ENDO 2026, the Endocrine Society's annual meeting, found the opposite.

What the New Research Found

Researchers analyzed data from the NIH's All of Us Research Program, linking electronic health records with Fitbit activity data for people who started a GLP-1 medication.[1] The cohort tracked physical activity before and after starting treatment, looking specifically at daily step counts and minutes of moderate-to-vigorous activity.

The results were clear, and not what many would expect: average daily steps fell from 5,047 to 4,487, and moderate-to-vigorous activity minutes dropped from 28 to 22 per day after people began their medication.[1] The declines were largest in men and in people reporting joint or muscle pain. Notably, the study found no evidence that losing weight on these medications led to an increase in physical activity at all.[1]

As the study's lead author put it: "While many assume that weight loss leads naturally to increased physical activity, our study suggests otherwise. The findings in our study reinforce that exercise cannot be optional for people taking these medications." Endocrine Society

Why This Matters More Than It Might Seem

GLP-1 medications are remarkably effective at reducing body fat. But they don't only target fat. Along with fat, many people on these medications are quietly losing muscle, and unlike fat, muscle doesn't come back quickly. Stanford Medicine

Recent research out of Stanford Medicine put this in concrete terms. In an animal model, mice treated with semaglutide lost about 25% of their body weight and substantially reduced their fat levels, but semaglutide also reduced their skeletal muscle mass. The bigger concern wasn't just the muscle lost upfront. It also reduced the muscles' regenerative capacity, meaning the animals recovered less well after an injury. Researchers noted this effect isn't unique to GLP-1s specifically. It's a feature of significant caloric restriction in general. Stanford MedicineStanford Medicine

Put the two findings together, and a pattern emerges: GLP-1 medications can reduce both the drive to move and the muscle's ability to bounce back, at exactly the time when staying active matters most for preserving strength and metabolic health.

The Takeaway for Anyone on a GLP-1

None of this means GLP-1 medications aren't a powerful, legitimate tool. They are. But this research is a good reminder that medication alone isn't a complete weight-loss strategy. Without an intentional plan for movement and muscle preservation, the easiest path is often to move less, not more, even while losing weight.

That's exactly why ongoing, personalized care matters so much during GLP-1 treatment. It's not just about the prescription. It's about regular check-ins, monitoring for the things a number on a scale won't show you, and adjusting the plan around movement, strength, and muscle health as treatment progresses.

If you're currently on a GLP-1 or considering starting one, this is a good moment to ask: does your care plan account for activity and muscle, or just the medication itself? At Mana Loa Health, this kind of whole-picture, provider-led support is built into how we work with every patient. If you'd like to talk through what that looks like for your own treatment plan, we're here to help.

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-The Mana Loa Health Team

Patient safety is Mana Loa Health's top priority. The information discussed on this blog is not intended to recommend the self management of health problems or wellness. It is not intended to endorse or recommend any particular type of medical treatment or advice. The information provided on this website is for informational purposes and not a substitute for professional medical advice, diagnosis, or treatment. If you have questions or concerns about your health, please talk to your healthcare provider. No information contained on this blog should be used by any reader to disregard medical and/or health related advice or provide a basis to delay consultation with a physician or a qualified healthcare provider.

References

• Maharjan S, et al. Exercise decreases among people taking GLP-1 medication. Presented at ENDO 2026, the Endocrine Society's Annual Meeting, Chicago, IL, June 13, 2026. Endocrine Society.

  https://www.endocrine.org/news-and-advocacy/news-room/2026/maharjan-press-release-endo-2026

  
  

• Nalbandian M, et al. Drug enhances muscle repair during GLP-1 weight-loss treatment in mice. Proceedings of the National Academy of Sciences, June 2, 2026 — reported via Stanford Medicine News Center.

  https://med.stanford.edu/news/all-news/2026/06/muscle-glp-1.html