DD has to ask for food, and then can help herself to it once she has permission. I also need to monitor the intake of her food because otherwise she doesn't eat enough of the right foods and would be happy for custard and yogurt to be her only sources of nutrition. On that note, even DH has to ask before helping himself to certain foods, just in case I was saving it to make dinner or a desert. He learnt the hard way, when he had to go to the shops a few times to replace what he ate, and would rather choose another option.