At the November 4 Elementary School in the Italian capital, for example, the menu includes rice and tomatoes, omelettes, boiled celery and oranges, served on biodegradable plates and cups.
For snacks, the children get fair trade cocoa-and-honey cookies and chocolate bars as well as bananas from the Dominican Republic, Colombia, Ecuador and Peru.
The revolution was long in coming in the land of pasta, first initiated in 1999 by then mayor Francesco Rutelli, a former Green who is now culture minister.
But Italy has long been a haven for quality cuisine, and taken a lead – as home of the not-for-profit Slow Food movement founded 20 years ago in the northern Piedmont region – in bucking the downside of fast-food culture.
Even Italian hospitals this year signed onto the "Slow Food" recipe for quality.
The schoolchildren, some of whom are obese, range in age from five to 10.
Plastic forks and knives have been banished, replaced by "grown-up" metal cutlery.
About 40 teachers concerned that the utensils are dangerous mounted a legal challenge to the change, but eventually backed down.
A dozen companies that have won tenders to supply some 145,000 meals a day to school canteens across the city must follow draconian rules.
Recipes developed by nutritionists must be followed to the letter, calories meticulously counted, and each meal must include a minimum of 30 percent fruit and vegetables, by weight.
"Everything is spelled out," says city official Silvana Sari. "There's no room for manoeuvre for the supplier."
All food is organic except for meat and fish products, up from an organic portion of only 10 percent in 2001, she noted. The cost per meal has gone up around 50 cents to five euros, of which parents pay two euros.
"It was easier to convince the children than the parents and teachers," Sari said, adding: "But now everyone is imitating us, both in Italy and abroad."