The military has canteens. Leaving the budget per meal per soldier aside, there is inherent difficulty to providing food for hundreds of thousands of people within a short period, and to providing such food at a relatively consistent level of quality. Most organizations tasked with providing such a large quantity of food over a short period of time resort to outsourcing supply to food service companies which generally provide processed food which is either frozen or shelf-stable. Fresh produce is difficult and "healthy and delicious" is practically a pipe dream.
There is a way to deal with this - hire an educated chef who can nurture relationships with many local farmers to negotiate supply, and actively manage the kitchen to make the best of the locally-sourced supply, not waste any of it, and put out a variety of dishes that, while not consistent in their contents from day-to-day, are consistently delicious. This is what Patrick Wodni [1] does for a Berlin hospital, but he's an exception because he was willing to take a large pay cut to work there. How many Patrick Wodnis are out there, for how many canteens would we need?
[1] https://www.nytimes.com/2018/10/05/world/europe/germany-chef...