We have Sweetie Saturday - the idea being that it stops the incessant questioning of 'Can I have sweets?' all week and then they can eat as much rubbish as they like on Saturday without asking. They are really good about giving me the sweets they get given by other children at school, for me to keep for them until Saturday. (I am not mean and often let them eat them there and then - but at least it means I have some control). However I eat sweets and chocolate all the time.....ALL the time.