Longevity & AgingBig Weight Loss Has a Skeletal Cost, and Exercise May Help Offset It
Obesity drugs like semaglutide and tirzepatide now produce weight loss once seen mainly after bariatric surgery, and doctors are asking what that does to bones. This review explains that obesity doesn't reliably protect against fractures, even though bone density is often higher. Any large weight loss speeds up bone turnover and lowers bone mineral density (BMD). Surgery has the biggest effect, with 8%–10% hip BMD loss in the first year after gastric bypass. GLP-1 drugs cause smaller declines, roughly 1%–2% a year, that mostly track the amount of weight lost. Adding structured exercise appears to preserve BMD during liraglutide-assisted weight loss. The authors argue that obesity care should protect bone and lean mass as well as reduce fat, and that high-risk patients need skeletal monitoring.
