io9 pointed me at this short 2007 essay, The Hidden Meaning of 2001 "The Monolith is an intergalactic food activist/critic, if not god of food. It is aghast when it finds the Earth apes eating twigs and bushes, being eaten by leopards and having turf wars over drinking water. The Monolith changes this: the apes are no longer meat, but begin to eat meat. Thus starts a revolution of eating."
It's worth reading to the end, the payoff is pretty funny.
In all seriousness there's probably something to this. I'd say that Kubrick is emphasizing the fact that we're just animals and eating is (now and for our entire history) one of the basic things we need to do to survive.