Here’s What Happens to Your Muscles When You Take a Break From the Gym

You Should Know: Life gets busy, and sometimes the gym habit falls apart for a while. Plenty of people come back convinced their muscles have morphed into fat. The good news? There’s no known process in the body that can make that happen; muscle and fat are entirely different types of cells, so one can’t become the other any more than an orange can become an apple.

Going Deeper: Here’s what’s actually going on: Muscle cells shrink without regular training, and fat cells can grow if eating habits stay the same while your energy expenditure drops. A 2020 review found fat tissue may also get better at storing energy once exercise stops, though most of that evidence comes from rats. These changes take time, though, and a few weeks off generally won’t lead to noticeable changes in muscle size. 

Takeaway: The softer look after a break comes from losing some muscle and possibly gaining some fat at the same time. So if you’re taking a gym break, staying generally active helps, as does keeping protein high while cutting calories a bit.

Bottom Line: Muscle can’t become fat, so a break won’t erase all your progress.