Ten years into her practice as a board-certified plastic surgeon in Austin, Texas, Dr. Ashley Gordon noticed something unexpected about certain liposuction patients sheโ€™d โ€œinheritedโ€ from older, retiring colleagues: They were slim overall, save for rock-hard belly fat.

โ€œThese were women who would have liposuction every couple of years,โ€ she recalls. After repeatedly having fat removed from their arms, thighs, and flanks, these sexagenarians and septuagenarians were anything but flabbyโ€”yet their abdomens told another story. โ€œThey could barely pinch the skin on their bellyโ€”it was tense [and] firm and felt hard,โ€ Dr. Gordon says. โ€œIโ€™d have to explain that it wasnโ€™t fat on the outside, it was fat on the inside.โ€