IF there was a Zombie Apocalypse, we'd really be in no real danger.
In Dawn of the Dead, both original and Remake, you'll notice that throughout the movie the Zombies start to deteriorate more and more as the movie goes on.
That's because with or without food, they're still dead and decomposing.
So at most we'd only have to hold off a couple weeks before they just decompose and stop functioning. Joints and muscles rot away, etc.
It's not like they're going to walk the earth forever, it's only a matter of time.
So 2 weeks worth of food and we'll be good.
yeah, it'll slim down the population quite a bit, but if your priority is Survival it shouldn't be too hard to stay safe and unbitten for a couple weeks.