What I read and know says that such a meal always includes different grains.
Coincidentally enough, in Lebanon, Christians have this grain dish on the night of the Epiphany, which is tonight as well - a platter of hot cooked barley wheat, sprinkled with almonds, pine nuts and raisins with sugar and, typically Lebanese, orange blossom water.
An Orthodox Christmas meal does not include any meats or dairy, but fish, dumplings and soups are common parts of the meal. My version included pickled herring, borscht with raisin bread, and blueberry perogies. Simple, tasty, and definitely more healthy than any traditional Christmas meal.