1.Mystery Fat is commonly found on seemingly in shape people. The person might seem skinny or fit, but has copious amounts of stomach fat and or thigh fat. Most commonly found on guys in the stomach and moobs, and found on girls in the thighs. Mystery Fat is easily hidden by loose fitting shirts and pants, thus making it ever elusive and unknown.
1.1 Often times Mystery Fat is revealed when a person takes off their clothes or wears revealing/tight fitting clothes.
Another less clever name for this natural phenomenon is skinny fat.
1. Garf: "Man, Chandler is so hot! I want her snatch"
Walter: "No, gross man, she has mystery fat, why do you think she wears jeans everyday?"
2. Spudberry: "Gross, did you see Grant's mystery fat in the locker room? He has the belly of an alcoholic"
Adolf: "Ugh, I know, what a Jew.... He's got a nice set of man tits though"