School lunches are a dumping ground for excess commodities
"The school lunch program is by and large a disposal system for agricultural commodities. The farmers grow too much of various things, the government buys it from them to support their prices and their welfare and then dumps it on schools." explains journalist Michael Pollan.
This is why you find mostly highly processed, fatty, terrible quality food in schools across the United States.
It's worse than you think: there are rules the require the school lunch program to buy food from the lowest bidder. Imagine if you were forced to only buy and eat the absolute cheapest food available to you. This is what's for lunch for most of an American kids' childhood. No whole, local or organic foods enter the picture in this system. They can't compete.