Consider the bean burrito: last year, in arriving from the factory wrapped in cellophane, each one had more than 35 ingredients, including things like potassium citrate and zinc oxide. This year: 12, including real cheddar cheese. Italian salad dressing went from 19 ingredients to 9, with sodium reduced by almost three-fourths and sugar — the fourth ingredient in the factory blend — eliminated entirely.

Statistics showing obesity rates growing faster here in Weld County than in surrounding areas gave the project impetus with district administrators, Mr. West said. The argument was then cinched by the numbers, which showed that going back to scratch would not cost more at all, but could in fact save the district money in the long run.

From the Colorado Health Foundation, a nonprofit group that has helped districts all over the state return to healthy cooking, Greeley got $273,000 in grants, which helped defray much of the $360,000 for construction and new equipment.

Equally crucial was the fact that the district still had a huge central kitchen space that was partly intact from the old days, including a bank of giant ovens that for some reason were never ripped out in the 1980s when cooking from scratch faded. That sharply reduced transition and projected operating costs. Even with 10 new hires in the core kitchen, Mr. West said, 10 net food service jobs were eliminated, since many lunch workers in individual schools were no longer needed.

“The biggest myth is that it costs more money,” said Kate Adamick, a food consultant based in New York and co-founder of Cook for America. She said federal reimbursement rules could actually give poorer school systems some advantages in shifting back to scratch, especially for meat, which many districts buy with deep discounts. Cooking the meat themselves, rather than paying a processor, can drastically reduce total costs, she said.

Meanwhile, the district’s first executive chef, George Coates III, who trained at the Culinary Institute of America and worked in high-end restaurants in Arizona and elsewhere, is plotting a food revolution. Mr. Coates, known in the kitchen as Chef Boomer, said he envisioned good food not just taking over the schools here in Greeley, but also eventually filtering back into homes, reconnecting parents with cooking through a system of recipe sharing — especially if, as he hopes, children go home and talk about the good food they are getting on his watch.