Weight Loss Drugs Linked to Reduced Exercise, Study Finds
New Research Suggests Potential Pitfall for Those Using Weight-Loss Medications
Individuals utilizing popular GLP-1 medications for weight management may be inadvertently reducing their physical activity levels, according to emerging research. A study slated for presentation at the Endocrine Society’s annual meeting, ENDO 2026, in Chicago this week, indicates that adults with obesity who have achieved weight loss through GLP-1 drugs like Ozempic or Wegovy have demonstrated a significant decrease in their physical exertion.
The findings suggest that while these medications, which include semaglutide, liraglutide, dulaglutide, and tirzepatide, are effective in reducing both fat and lean muscle mass, this loss of muscle makes physical activity crucial. “Physical activity is essential for preserving strength and long-term health,” stated Dr. Sajana Maharjan, the study’s lead author from HSHS St. John’s Hospital in Springfield, Illinois, in a press release from the Endocrine Society.
Study Analyzes Fitness Tracker Data
This study, reportedly the first of its kind to make such a connection, analyzed data from a National Institutes of Health research program. The program linked participant records with activity data from fitness trackers. Researchers examined information from 753 individuals diagnosed with obesity who began treatment with a GLP-1 medication. The group was predominantly female, with an average age of 52.7 years.
A comparison of activity levels before and after initiating the medication revealed a drop in the average daily step count from 5,047 to 4,487. Furthermore, moderate-to-vigorous physical activity decreased from 28 minutes per day to 22 minutes per day. The most pronounced reductions in activity were observed among men and individuals experiencing joint or muscle pain. Factors such as age, heart failure, or a history of stroke did not appear to influence these results.
Exercise Remains Crucial for Health
Contrary to the assumption that weight loss achieved through these medications might inspire greater physical activity, the study found no evidence to support this. “The findings in our study reinforce that exercise cannot be optional for people taking these medications,” Dr. Maharjan emphasized. “People need targeted interventions that encourage physical activity alongside medication for obesity.”
It is important to note that the study was retrospective and observational, meaning it identified an association rather than a direct cause-and-effect relationship. The demographic makeup, primarily middle-aged women, could also limit the generalizability of the findings. Additionally, the research did not account for pre-treatment exercise habits, motivation levels, or physician guidance.
Expert Perspectives on Weight Loss and Activity
Dr. Peter Balazs, a hormone and weight-loss specialist with practices in New York and New Jersey, concurred that weight loss does not automatically translate to increased mobility or a greater desire to exercise. He explained in a recent interview that a calorie deficit can prompt the body to conserve energy, potentially lowering metabolic rate.
“Additionally, side effects of weight-loss medications, such as nausea, fatigue, or gastrointestinal discomfort, may further reduce a person’s ability or desire to be physically active,” Dr. Balazs added. He stressed that for those on GLP-1 medications, exercise is “not optional.” He advised patients to integrate resistance training and daily movement, like walking, to preserve lean muscle mass, maintain metabolic health, and support long-term weight management.
“Exercise plays a critical role during weight loss,” Dr. Balazs stated. “Without adequate physical activity, a significant portion of weight loss may come from muscle rather than fat.” He also highlighted that a personalized approach is necessary, with exercise timing, intensity, and type tailored to an individual’s fitness level, health status, and body composition. This is particularly relevant for individuals with a high BMI who might face mobility challenges or have lower baseline fitness, to mitigate injury risk and prevent burnout.
Contrasting Clinical Observations
However, not all medical professionals share these concerns. Dr. Amanda Kahn, a board-certified internist and longevity expert, noted that her clinical experience differs from the study’s conclusions. “Weight loss often serves as the impetus that motivates patients to become more physically active and more engaged in their overall health,” Dr. Kahn, based in New York, shared.
Dr. Kahn believes the success of GLP-1 therapy is contingent on provider expertise. “When these medications are prescribed thoughtfully – with attention to nutrition, resistance training, body composition, and laboratory monitoring – they can help patients lose weight while becoming healthier, stronger, and more motivated to exercise,” she explained.
As a peptide prescriber, Dr. Kahn cautioned against a hands-off approach. “In my practice, if a patient is unable to exercise, is not meeting protein goals, or shows concerning muscle loss on body composition analysis, I will often hold or adjust the medication – because preserving strength, function, and metabolic health is just as important as weight loss,” she stated.
Dr. Kahn concluded that if a patient experiences excessive fatigue, nutritional deficiencies, or significant muscle loss while on GLP-1 medication, it indicates a need for “close clinical oversight” and better monitoring, rather than solely a problem with the medication itself.
