The food will be healthier and fresh, but due to it being fresh it will cost more, about a two dollars more than the average price for the unhealthy meal
Benefit: higher health means higher fulfilment means higher mental agility means higher productivity means higher school prestige means higher revenue means higher capacity to expand means higher wage and so on
cost: short-term expense hence question of affordability, also perhaps there's no demand for health so the new program is unsuccessful and people want their burgers and fries lol and so on
If people approve of the new program, it could benefit me politically by helping my chances of reelection. One possible social cost is that parents might become upset if the price of lunch increases.