I was just thinking about whether CC have a right to ban certain foods and I suddenly remembered my primary school. In the '80's our headmaster decided to make hats compulsary - my mum was a hat person so I already wore one but lots of parents weren't happy. Now it's governmental guideline (in NSW) that children need a hat and 3/4 length sleeves at schools and CC for outdoors play.
Early nutrition can have big impact on health in later life so I see it as a similar issue. For now we're getting used to it but by the time our grandchildren start school it will probably be as accepted to have dietary guidelines as it is to have sun-smart regulations.