Is it possible for food to be conjured in the world of TES? I dont mean teleported from some other part of Nirn, but actually born from Creatia, I don't really know where to begin looking for any evidence about this.

It could be possible. But I doubt it would, otherwise, everyone on Tamriel would be without poverty, happy, well-fed and living on Comrade Lenin's huge magicka farm.

That would be assuming someone with enough power to reach through the Deadric realms into the Aetherius would also be benevolent enough to share with everyone.

PS : I dont really go with the idea that one could simply pluck food from the Daedric Prince's spheres, as obviously they would hold some aspect of the Prince you took it from. Which certainly doesnt come off as healthy to me, and they hoard their creatia, so even if it did work like that I would be willing to believe it would phase back into the Prince's being if one did not expend power to keep it in Nirn, so not really good for sustenance either.

Conjuration in the game world is pulling objects or creatures from Oblivion, not Aetherius. I figured the only things that can get at the creatia are the Towers. And besides, to be able to take pure creatia and turn it into food is probably beyond the scope of mages; though I'm no scholar on the subject.

battlemages can summon water.

http://www.imperial-library.info/obbooks/ionith.shtml

Yes, that is common magic from oblivion but as I suggested oblivions ability to sate one's thirst would probably be zero. Aetherous is pure creatia though, as mentioned the Imperial Battlemages (no common Mage) could create water. but this argument is probably pointless if you exhaust yourself doing this spell as one would expect from reaching Aetherius.

Yeah don't pay any attention to those knuckleheads...I trained as a Battlemage and I had the whole "wear a blind fold and we'll summon water" trick pulled on me more than a couple times. They call it "earning your yellow stripes" at the War College.

this brings up some hilarious situations. imagine a mage summoning food, eating it, digesting it, and then later going to the bathroom. afterwards the excement returns as the spell expires, and you now have a bunch of daedra in oblivion getting PO'd that their realm is getting full of dung. especially ones that were excited to eat something only to find it replaced with dung.

maybe that's why the daedra invaded in the first place, and why summoning food is now forbidden.