Muscle does not convert to fat when exercise stops

Scientists and fitness experts have confirmed that muscle does not turn into fat when people stop exercising. The two tissues are completely different cell types, and one cannot become the other.

What actually happens is simpler. When someone stops exercising, their muscles begin to shrink. This process, called atrophy, can start within just seven days. At the same time, if that person keeps eating the same amount of food, their body stores the extra energy as fat. So the muscles get smaller while fat increases.

This creates a visual effect that looks like muscle has changed into fat, but it has not. Losing muscle also lowers the body's resting energy use, which makes fat gain even more likely over time.