I've found since the release of Minecraft 1.7, that my hunger bar decreases whilst I'm AFK on my private vanilla server. The wiki page shows a list of actions (e.g walking, running, jumping, etc) that will increase hunger and states that hunger shouldn't increase when not performing these actions.
I've played on three different PCs on my own vanilla server, and I have the problem on every system. Difficulty is on easy, yet I'm loosing one drumstick from my food bar every 20 seconds.
Have I stumbled on a bug, or am I missing something else?