No child should have to endure the entire school day without eating. It's partly for their sake. Kids needs that energy to pay attention. Without it, they might as well be at home. Why be at school and put yourself at risk of being shot when you're not even going to retain any of that information anyway? The other reason why kids shouldn't have to endure an entire school day without eating is because they become little monsters and that's not fair to the teachers.
I've worked with children for years and they don't understand that when they are hungry or tired, they become monsters. Actually, many adults don't realize that either. If the world was properly fed and rested, we'd all be fine. If we were all high too.