You are being sarcastic right? There is no way that muscle turns to fat ...Muscle mass and fat are two different animals: Muscle is active tissue that burns calories around the clock even as you sleep, kind of like an engine running in neutral. When you move around, you burn more calories, just like a car will consume more gas the faster you go. Fat, on the other hand, is just a storage of excess energy. It does nothing but sit there with its sole goal in life to be a spare tire around your waist until you put in the effort to burn it off.
Bodyfat is not particularly useful except as padding against bumps, as insulation to preserve warmth, and as a convenient surface where you can balance a can of beer while watching the game. You need some bodyfat to stay healthy of course, but unless you're walking around with razor-sharp abs and sunken, fat-depleted cheeks year-round, you probably have nothing to fear.