I think the idea is that it limits initial favored food or drink for sapiants to what the civ can produce itself - after all it doesn't really make sense for a dwarf to absolutely adore giant parakeet meat... When that civ has literally never had any sort of contact with one and lives on the other side of the world from where giant parakeets can be found, or to love Gutter Cruor when nobody farms it unless some suicidal group of people seeks out the plant it comes from, at great risk to thier own lives, or to like Sunshine when really only nobles could afford to even get one mugful.
So the idea would probably be either limiting it to civ specific (anything they can access in thier general area,) domestic food and drink only (what they can grow and rear themselves is what they prefer,) or making it totally random (how it currently is.)
As to animals, it'd be more of a preferred prey. Dragons prefer to eat dorfs, but will eat humans if they're more plentiful, more convenient, or a bigger threat. This could also extend to certain animals attacking certain things for food - bears could have an added behavior to attack your hives for honey, giant predatory animals might have a general [PREFERRED_PREY:LARGE_LIVESTOCK] to trigger them to attack things like horses or yaks over things like dogs or chickens - but won't keep it from chowing down on those too if they're a more convenient prey item or attacking it.
Could even result in "beast raids" - a sort of soft siege like ambushes where one or more of a given predatory animal move into the area with an announcement.
"A group of [predatory animal] has come into the area! Protect the livestock!" with the message varying based on the preferred food.
Prefers large livestock - The animals in question will seek out your cows, horses, and so on. "Protect the livestock!"
Prefers small livestock - The animals will seek out your domestic fowl, rabbits, and such. "Protect the livestock!"
Prefers sapaiants/dwarves/etc. - The animal prefers to prey upon sapiants or your player race specifically. likely mostly applicable to good and evil creatures such as Nightwings. "Raise the alarm!"
Prefers food items - The animal behaves like a curious eater, but will be very aggressive in raiding the fields or other food stores, including attacking dwarves hauling food items such as raw fish. "Secure the food stocks!"
Prefers honey or some hiveable animal - Will attack hives if left unattended, toppling the hives and consuming the products. "Protect the hives!"
In these situations, either the items will be consumed on the spot, or the animal/citizen/visitor will have parts consumed in combat or possibly after killing the target, if they manage to (resulting in a gnawed/gnawed and mangled corpse, depending on how badly the predator mauls the target.)
Maybe all that's been suggested somewhere before. I dunno.