No - muscle cannot turn into fat; they are different tissues with different cells and no conversion path.
What actually happens: muscle fibers shrink from disuse while fat accumulates if eating stays at training levels - MRI detraining studies show muscle size persisting for weeks while fat deposits shift separately. The soft look reads as conversion; it is really one tissue shrinking and another expanding into the space. The good half: regained muscle comes back faster than it was first built. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper .
What to do
Common questions
Does muscle turn into fat when you stop training?
No - muscle cannot turn into fat, because they are different tissues with different cells, and biology offers no conversion path. What actually happens when you stop training is two separate processes running in opposite directions: muscle fibers shrink from disuse (atrophy), and fat accumulates if eating stays at training levels while burning drops. MRI studies of detraining show this precisely - in one experiment, muscle size built over six weeks of training persisted for weeks after stopping, while fat deposits shifted inside and around the muscle separately. The visual result - a soft body where a firm one was - reads as "muscle became fat," but nothing converted; one tissue shrank and the other grew into the space. The encouraging half of the same science: lost muscle is re-gainable faster than it was built the first time, so a training break costs less than it feels. The practical rule: keep protein up and stay somewhat active through a break, and the "turning to fat" effect mostly disappears - the scale lies about which tissue is doing what.