This is totally absurd.Even in communism there was no such stupidity.You had 3 choices:
1.Eat what you bring from home
2.Your parents to pay for you to eat cooked food at the schools cafeteria.What they served was pre-established.
3.Some classes parents would make a decision on a PTA for some bakery to deliver something their kids to eat.All would had the same thing ( some form of pastry + yogurt or milk because here the school lunch break is meant for you to have a snack to hold the hunger until you go home to eat so it lasts 20-25 minutes )
It is the same today,but I think that the cafeterias are mostly closed(because every food used to be stew with salads,very healthy but very unpopular ) and replaced by stores and well it would come somewhere between barbecue/fast food .
But the government saying what your kids should eat even in communism would have been found ridiculous.Schools and teachers are there to educate their kids.How their kids feed and how they are being raised is their parents responsibility and problem.Unless their is some clear abuse the schools and the state have no job getting involved.