Heyy, an incarnation of this topic that hasn't turned into a raging debate.
(Don't mind me, I've just been on this forum for too long.)
Well, I'm surprised at the amount of people here who stand by the theory that there are animals in the Pokemon world. It used to be a very uncommon theory. Even though, canonically, it could go either way, it's at least supported by the fact that, well, humans are animals after all.
(And then there's the General Pokemon Discussion forum, where people try to claim that humans are actually Pokemon, which aside from being totally silly, is disproven by canon five times over.)
So yeah, if there were animals in the Pokemon world, they'd be fairly uncommon, due to having to compete with Pokemon and all. I'm sure there'd be a few niches for them, though (insects come to mind--they're so small that they'd fulfill a lot of roles way better than Pokemon would.) So it's not a stretch to say that humans would have some domesticated they could use for food.
This is of course assuming that Pokemon have near-human level intelligence, (obviously animalian Pokemon could be killed and eaten no problem) because aside from the obvious moral issues with killing a fully sentient creature, there would be no logical way to breed Pokemon for food, considering they would know what was happening and could just use their nifty powers to escape or fight back rather easily. The concept of hunting and killing wild Pokemon would still be open, though--I'm sure there would be people in that world who wouldn't care about the moral issue. And anyways, Pokemon kill Pokemon for food. :/
So in a world with sentient Pokemon, the options are: people are vegetarian and eat meat substitutes (and also things like Chansey eggs and Miltank milk. I'm sure farms could cut deals with groups of these Pokemon to provide them with care in return for these products), or people have access to animal meat one way or another.
But of course, as everyone else has mentioned, you don't really have to mention where the food comes from.
I don't even think meat has shown up in my fic, since the main character is an unofficial trainer, can't win money from battles, and mostly just lives off cereal and ramen. xP
~Chibi~;249;;448;