I don't know what it is like in the US, but the school food guidelines are relatively good for the school lunch and snack meals. It is all hot food, normally fish and potatoes, or some pasta and the like. It isn't the "fast food" I see from the US ... in movies... so that might not be the reality.
A commune would be alright - but 24/7, I think I would get annoyed with people!
The food from US schools is the worst of the worst processed garbage from most of my experiences. And sadly, that is what the students gravitate to eat. They would pass on the salad bar and fresh fruit served with their meal. But processed chicken nuggets, flimsy burgers, and greasy grilled cheeses were student favorites. I wouldn't touch anything from our school cafeteria that wasn't whole food. Big Yikes on US school food! It is just another way of keeping poor people poor with awful food choices. Don't even get me started on how badly the few kids whose parents sent them in with homemade meals were mocked and ridiculed even though they had much better food options than their peers. Truly heartbreaking!
This might be an interesting overview:
https://www.oph.fi/en/education-and-qualifications/school-meals-finland
We have guidelines in the US too, but they are minimal and our food & drug administration is weak. All of the worst, toxic, agro-industrial companies make the cheapest food possible for these poor schools to buy.