SouthernWorldwide.com – A recent study suggests that individuals using GLP-1 medications for weight loss, such as Ozempic and Wegovy, might be making a significant mistake by reducing their physical activity levels.
The research, slated for presentation at the Endocrine Society’s annual meeting, ENDO 2026, in Chicago, indicated that adults with obesity who achieved weight loss through these medications experienced a “significant reduction” in their physical activity.
Dr. Sajana Maharjan, the lead author of the study from HSHS St. John’s Hospital, highlighted that GLP-1 drugs, including semaglutide and liraglutide, lead to the loss of both fat and lean muscle mass.
This makes physical activity crucial for maintaining strength and ensuring long-term health, she emphasized.
The study, described as potentially the first of its kind, utilized data from a National Institutes of Health research program that correlated participant records with information from fitness trackers.
Researchers examined data from 753 individuals with obesity who had started a GLP-1 medication. The group was predominantly female, with an average age of 52.7 years.
When comparing activity levels before and after starting the medication, the average daily step count dropped from 5,047 to 4,487. Similarly, moderate-to-vigorous physical activity decreased from 28 to 22 minutes per day.
The study observed the most substantial decreases in physical activity 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.
Contrary to what one might expect, the study found no evidence that weight loss achieved through these medications led to an increase in physical activity, according to Dr. Maharjan.
“The findings from our study underscore that exercise cannot be an option for individuals taking these medications,” she stated. “Targeted interventions are needed to encourage physical activity alongside medication for obesity management.”
The study was retrospective and observational, meaning it could only identify associations rather than direct causation. The researchers also noted that the participant pool, largely comprising middle-aged women, might limit the generalizability of the findings.
Other factors not accounted for in the study include pre-treatment exercise habits, individual motivation levels, and the extent of physician guidance received.
“Indeed, being in a calorie deficit can prompt the body to conserve energy, leading to a lower metabolic rate,” one expert explained.
“Furthermore, side effects associated with weight-loss medications, such as nausea, fatigue, or gastrointestinal discomfort, can further diminish a person’s capacity or inclination to engage in physical activity,” the expert added.
For those using GLP-1 medications, exercise is “not optional,” according to Balazs. He advised patients to incorporate resistance training and consistent daily movement, like walking, into their routines to “preserve lean muscle mass, maintain metabolic health, and support long-term weight management.”
“Exercise plays a critical role during weight loss,” Balazs commented. “Without sufficient physical activity, a significant portion of the weight lost may be muscle rather than fat.”
Balazs also pointed out that a one-size-fits-all approach is not suitable, as the timing, intensity, and type of exercise should be tailored to an individual’s fitness level, health status, and body composition.
“This is particularly important for patients with a high BMI who might have mobility limitations or lower baseline fitness levels,” Balazs stated. “It’s crucial to consider injury risk, long-term adherence, and the potential for early burnout.”
However, Dr. Amanda Kahn, a board-certified internist and longevity expert, expressed disagreement with the study’s conclusions, suggesting they do not align with her clinical observations.
“The success of GLP-1 therapy is directly linked to the provider’s expertise,” she elaborated. “When these medications are prescribed thoughtfully—with attention to nutrition, resistance training, body composition, and laboratory monitoring—they can assist patients in losing weight while becoming healthier, stronger, and more motivated to exercise.”
Dr. Kahn, who prescribes peptides, does not advocate for simply prescribing a GLP-1 medication and expecting patients to “self-manage.”
“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 as important as weight loss,” she explained.
If a GLP-1 patient experiences excessive fatigue that prevents exercise, develops nutritional deficiencies, or loses significant muscle mass, Dr. Kahn warned that this indicates a “monitoring problem” rather than a medication issue, as these medications “require close clinical oversight.”
