Well do they just like in this universe we eat animals?

Yes. Some Pokemon, such as Slowpoke, Far'fetchd, and Appletun are canonically eaten.

Humans have sustained a diet for very important reasons. The more diverse a diet the better at energy expenditure and energy intake you can be. But eating isn't just for fuel- it can rejuvenate and promote cell division and let your brain function.

Slowpoke tails the Slowpoke drop themselves/don't feel pain from it, so that's there. Then a lot of other stuff, although I don't really enjoy eating Pokémon and avoid the Klawf meat and such while playing Violet (but Slowpoke tails are fine because they don't mind.)