There was a "feature" like this in another roguelike (actually more of a *band) I played. Can't remember specifically which one, but when traveling the overworld map one would eat and drink from their pack as-needed. Once you ran out, travel would stop and the player would have to go screen-by-screen to either find food or a stream, and might eventually die.
So I deffinitely think this is a good little idea. I've actually modded features like this into other games which have "hardcore needs" mods like Fallout 3 and New Vegas before. It's almost required when you're playing an action game. I mean it's realistic to need to eat and drink, but actually somewhat UNrealistic to have to be concerned with it at all times.
Hell, I'll bet a good number of you reading this post are eating food right now, and didn't even realize you'd gotten anything to eat yet*. In real life, eating and drinking are so necessary, they can almost become automatic.
Like me. I have a tall glass of coffee and barely even realized it was there until I wrote this post.
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Kohaku brings up a point. We wouldn't want adventurers automatically munching on their raw dragon meat they were lugging around for whatever reason. Especially if diseased (interaction-laden) meat is a possibility. It might be best to have some kind of separate "lunch box" list, where food you wanted automatically eaten could be put. Food that was just loose in your pack wouldn't be eaten automatically, but the waterskin full of booze and the sammiches you put in the lunch box would be.