What's this "poke-relax" thing?
If by food you mean the coffee beans, the first time you buy a drink at a pkmn center bar (each day), the bartender will give you a handful of them. Then after you cleared some events in the game, you will have access to the Poke-lago where you will find a bean tree on the first island. Hit it to make beans fall on the ground and pick them up. (you can pay back some beans to upgrade the island, until it features a giant bean tree)