US here. Slop. I was fed slop. A random mishmash of low quality processed food. Peaches soaked in sugar was the highlight. Instant mashed potatoes served with an ice cream scoop. Burgers that always tasted like they’d been freezer burned and heated in a microwave. Served on stale buns. If things could go stale, they would be served stale. Ketchup served as a vegetable. Imagine prison food and you’re not far off.
Germany:
In the school cafeteria there was a choice between two meals, usually some meat with greens on the side, a slice of pizza, or burgers. Nothing special, but also not too bad. And always a bowl with yogurt that had fruits in it as desert, which was usually the highlight.
In higher grades, I started going to the bakery on the other side of the street for a sandwich (but not a flat sandwich, I mean a bun with cold cuts and salad, aka. "belegtes Brötchen").
Lessee, in the US I remember getting on different days:
A hot dog
A hamburger
a rectangular pizza slice of bad pizza
An ice cream scoop of spaghetti
A piece of backed chicken
All of that was served with a small carton of milk and probably some sides that I can't seem to recall at the moment.
Denmark: Sourdough rye bread (rugbrød) with cold cuts, sometimes chocolate. Sometimes chocolate on WHEAT, if mother had love in her heart. Cucumber, carrots, or some fruit for health.
This was in the olden days, in the 80s/90s. I assume it's basically the same now, possibly more appetising.