Look it up – I did. The Oslo Lunch was a real thing pre-war – an experiment that worked in improving children’s health via better nutrition. It was essentially whole-meal bread, cheese, milk, and fruit or salad. Not a bad thing overall, and apparently led to weight and height gain for under-nourished children in Norway and Great Britain.
I believe it featured here in Australia and I can vaguely remember some mention of it at Governor Stirling High School in 1965.
School lunches in my childhood in Canada and the USA were generally either a cafeteria hot meal in the more affluent areas or home-packed in all the others. In one memorable junior high in Calgary there was a policy of sending the students back home for their lunches unless there were such dire weather conditions that they could not go out. Even then, one had to have a signed form citing ” inclement weather ” to be permitted to huddle in the school assembly area for the lunch hour.
I think, in retrospect, it was just a move to get the students to clear off and let the staff members have their lunch hour to themselves. I wonder if they were required to walk a mile either way four times a day…Mighta been good for their lard asses.
Note – inclement weather in Calgary generally had to be an active prairie blizzard with drifts of snow higher than 3 feet. We did not have ” Snow Days ” in the 60’s. Snow was an accepted fact of life. After the blizzard blew out you went to school, drifts or not. I bicycled into a parked white Oldsmobile that was buried in a drift one year. Now that’s educational.