As always, I say no to this sort of thing. This is a game, it's about entertainment, not about simulating real life, so if a certain feature isn't entertaining, it has no reason to exist in a game. Now, sometimes, occassionally, players will ask for a bit more realism in games, but there needs to be some limit, because a completely realistic gameplay experience would simply not be entertaining, but in that case, where do we draw the line? "Fun" sounds like a good place. Would adding the need to eat be fun? No, I say it would not be, aside from the Sims, I have never, NEVER once in my life been entertained by needing to find food for my character in a video game before, even though I've played games with this requirement, I once even installed a "basic needs" type mod for Morrowind, it wasn't necessarily a game ruining feature, because it's not like you need to constantly eat, but it's still a feature that I'd rather not have, and the only reason I was fine with it in the Sims is because that's pretty much the point of those games, without micromanaging the lives of fictional entities, there would be nothing to the games.
If Bethesda MUST add this, then they should make it optional, like how Obsidian is making "hardcoe mode" optional in Fallout: New Vegas, that way, at least those who don't want it can turn it off, though personally, I'd say even programming the feature into the game so it can be enabled as an option would simply be a waste of time, but hey, it's better than being forced to eat and drink whether I want to or not, and it's the only way both crowds can be satisfied.
Also how hard is it to eat maybe an apple of a loaf of bread once every few hours? Not difficult and you can hardly say that 0.5 (weight) loaf of bread takes up alot of room can you.
That's just one more reason why having the need to eat in games is pointless, it doesn't add any sort of meaningful challenge since, as you said, in a game like the Elder Scrolls, food is hardly difficult to come by. Yet while it doesn't add meaningful challenge to do the game, it does add additional frustration, and does it add extra fun? I would say no, so why should a game have a feature that is neither fun or challenging but is frustrating? The answer is that it shouldn't.
Let me ask you this: In Lord of the Rings, did the characters explicitly have to eat/drink/sleep? Yes. Did that add to the story? Yes, because it intensified the danger of barren areas and long trips and acted as an impetus for adventure and immersion. Were they ever described as going to be bathroom? No. Why? Because it doesn't add to the story. You can take a crap anywhere
Those eating scenes were also not exactly the most interesting scenes in the story, I could argue, and when they were interesting it wasn't because it was interesting to read about the character's eat, it was because they actually served to further the story somehow, in other words, they served to contribute to the experience, now in a video game, on the other hand, unless simulating real life is the entire point of the game eating adds NOTHING to the experience and should NOT be necessary.
This would be pretty fun, and it wouldn't be invasive at all,
I disagree, on both accounts. Needing to eat is in no way fun and just the need existing would be invasive in its own right, I get enough of that in real life, there's no need to have it in a game too.
I think the reason why people bring up bathroom stuff, is because the reason why they don't want the need to eat and drink regularly, is the same reason why they don't want to have to go to the bathroom. The same arguments that apply to eating and drinking, could fit bathroom breaks.
There's also the fact that once you start putting in the need to eat and drink, the only thing separating it from needing to find a toilet regularly is just how far into the realm of realism you want to go.