My dad sent me a book about my home town in the Shenandoah valley that had a tiny little part about a lady that was remembered for feeding kids a hot lunch for 10 cents. This took place in the 1940’s and the kids who ate at “gasp” her house were too far from home to walk back and get lunch.
She fed them what her own kids got and it was not grand. Gravy bread was often the main course. Veggies from the garden either fresh or canned were often on the menu as well. Moochelle would have mixed feelings about the menu. But dang it the kids did eat it or else.
Mondays were hot dog on a roll, baked beans, dessert (usually canned fruit or jello) and milk. For all 12 years! Of course, the foods were not "fast food" - all was cooked on site. And they didn't cater to picky eaters. You were free to bring your lunch from home, but ate in the gym instead of the cafeteria if you did that.
For the most part kids were in pretty good shape physically - we had outdoor recess twice a day. And played outside every afternoon after school.