Scientists looked at people with obesity who started using popular weight‑loss drugs such as Ozempic, Wegovy, Mounjaro, and Zepbound. These medicines belong to a group called GLP‑1 receptor agonists.
When people lost weight with these pills, they moved less. On average, daily steps dropped from about 5,000 to 4,500. Time spent doing moderate‑to‑vigorous exercise fell from 28 minutes to 22 minutes.
The researchers used data from the NIH’s All of Us program, which links health records with Fitbit activity numbers. Out of 1,950 adults who began the medication, 753 had enough Fitbit data to be studied. Most were women, and the average age was 53.
Men and people who said they had joint or muscle pain showed the biggest drops in activity. Age, heart problems, or a past stroke did not change the results.
These drugs not only cut fat; they can also reduce lean muscle. That makes staying active even more important for keeping strength and overall health.
“Many think that losing weight will automatically make people more active,” said study leader Dr. Sajana Maharjan. “Our findings show exercise cannot be optional for anyone taking these medicines. We need programs that encourage movement alongside medication.”
This is the first large study that used wearable fitness‑tracker data to see how adults on GLP‑1 drugs change their daily activity.