C.M.
As far as I know, you don't. Its the kids who were invited to the party and they're the ones you should be most concerned with. If nothing else there is always the option of finger food. You can bring a few platters of sandwhiches, veggies and maybe some cupcakes. No adult/parent goes to a childrens party @ a play place and expects to be fed.
Dont fret my friend, its the children you cater to.