NEW YORK, June 7 -- She lost 38 pounds in seven months on semaglutide. Her clothes dropped two sizes. Her blood pressure normalized for the first time in a decade. And when she looked in the mirror, she still saw the person she used to be.

This experience - described by patients across social media as "ghost fat" - has become one of the more quietly unsettling phenomena in a weight-loss era defined by pharmaceutical intervention. The body changes. The brain, it turns out, takes considerably longer to catch up.

GLP-1 receptor agonists like Wegovy and Zepbound have now been used by an estimated one in five American adults at some point, according to figures cited by the University of California. They suppress appetite, slow gastric emptyi...