Researchers have uncovered a surprising new role for the HSL protein: beyond breaking down fat, it also works inside the nucleus of fat cells to keep them functioning properly. When HSL is missing, fat tissue doesn’t expand as expected— instead, it shrinks, leading to lipodystrophy. This unexpected discovery helps explain why both obesity and fat-loss disorders share similar health risks, and it opens up fresh paths for understanding metabolic diseases at a time when obesity affects billions worldwide.