In my country, there’s no US style cafeteria (instead it’s a canteen where it’s up to the student if they want to buy anything) some bring their own lunches (home or leftovers) to school, so why do American kids rely on cafeteria food instead of bringing their own?
I mean, is cafeteria food across American schools that bad? It depends on where one resides or if they attend a public or private school. In my case I went to a private (Catholic) high school and the food there is actually good (& cheap when converted to USD).
When the government allowed corporations into the schools with soda and snack machines in exchange for a kickback in the 80s, any hope of a bureaucrat looking out for the kids’ health was dead. Once they could use the excuse that most kids weren’t making use of a subsidized nutritious lunch(very loosely using the phrase) because they were bringing their own or eating their lunch from the machines, they didn’t even need to try any longer.
https://www.nuvending.co.uk/news/history-of-vending-machines-in-schools/
(Ironically, a post from a corporation installing the vending machines points but it makes the necessary points)