Obelix eats extreme amounts of food when he can, but he apparently simply needs it to stay healthy. Besides, he eats with pure glee; there are clearly no emotional issues behind his superhuman ingestion.
Tons of people would break bones (and worse) if it were a realistic universe. But since it's "Asterix", nobody gets seriously hurt, only comically roughed up (black eyes and such).
We see a cooked boar being eaten in the very end. We haven't seen that particular boar alive, but we have seen other boars throughout the movie that expressed some emotion.