I struggle to keep a healthy balanced diet in the real world so I would rather not have to try and keep one in a fantasy world. I want my avatar to look a certain way, I do not want to have to micro manage the type of food I'm eating to maintain my look. I think this is one realism step to far for me... sorry!
While I applaud the idea Beez I see one drawback with this. What would happen if the Devs put in a spell/condition that affected a person's nutrional needs in a negative way? If the avatar;s looks could be changed by the diet or lack there of then it would also make sense that the NPCs and more intellegent AIs would also be able to affect the avatar in more hampering ways. For instance, say a evil priest casts hunger or thrist on a character that they have to consume 3 or 4 times as much food as they normally would and if they did not have the supply on hand that the character would die.