I have it written in my contract under the food section that I provide one meal and two snacks. I also have it that should a child require food due to a medical condition that it is provided by the parent. This is meant for things like lactaid or soy milk etc but I would enforce that policy in this case in the sense that mom is free to send in the extra food required and then I would set up the day so that every hour child sits at the table and eats what you put in front of him so he maintains balance between the food groups and it isn't a just whenever he gets bored or there is a lull in the day or he doesn't want to do what the group is doing he will just eat.