Doctors say rapid weight loss on GLP-1 drugs can leave feet bonier, looser or more painful, with some patients reporting they dropped a full shoe size.
25% to 40% of weight lost during GLP-1 treatment may come from lean mass, and thinning fat pads under the heel and ball can reduce cushioning and make walking feel like "pebbles."
Dr. Claire Morrow said people who lose 15% to 20% of body weight in under a year may face higher risk because skin and soft tissue may not adjust as quickly as the weight comes off.
About 1 in 8 U.S. adults reported using a GLP-1 drug in a KFF poll last year, widening attention on side effects that are not listed among the medications' most common risks.
Doctors recommend slowing overly fast loss through dose discussions, maintaining protein and resistance training, and remeasuring feet or adding inserts as weight changes.