My kidlets' dad is a cheap and easy kind of guy. Pizza, sandwiches, candy etc. I am going to put it to him this way. "Girl had ADD. Her councilor recommended cutting out food dyes. I also cut out wheat as that is a big ADD trigger. It has made a huge difference so I recommend no wheat/food dyes for the kids. You can feed them what you want but girl is calmer and quieter and better behaved."
Kids learn very quickly about the difference between mom's house and dad's house. Stand your ground and they won't fight you.