1.Because he's always stuffing his face with food and beer.
2. IT's also a بیئر gut( Yes that is a real thing)
3. For homer, exercise is losing the remote inbetween the سوفی, لٹانا cushions, and looking for it for an گھنٹہ all around town in his car then five منٹ after comeing ہوم and drinking a beer, him finding it. For most that's stupidity, but for Homer, that's exercise!