The Walking Dead: Terminus season.
This movie is very similar to the TV show The Walking Dead, specially the Terminus episodes.
It's a pity that nobody knows this movie, but they do know the TV show and love it. I mean, this movie was released (2011) before the Terminus season of The Walking Dead (2014), but if someone watches it now it doesn't look so original and fresh...
I think The Day was a good example of a post-apocaliptic world with cannibalism. An example filmed before The Walking Dead. :)
By the way, the music reminded me a lot of 28 weeks later movie.