Serve the menu you want and have a side table with more filling party food for guests to graze on, to bulk out the menu. You definitely don't want people to leave hungry. If its something like a tasting menu then people will be hungry. But you can have a second round of food that is more humble while the reception continues- carby, affordable tapas. Just make sure guests know its coming so they can enjoy the nice meal without worrying about how little food or if they will even like it.