The move is believed to be the country's most ambitious plan for healthy eating in schools and adds an estimated pound;4 million to the authority's food bills next year.
It comes in response to health fears in the deprived city of 250,000 people. Levels of type 2 diabetes associated with poor diet were the highest in Britain, data analysts Experian said last year.
But for the past year, primary and special schools have had the opportunity to provide free, healthier breakfasts, lunches and after-school snacks for all pupils.
The decision needed special dispensation from the Department for Education and Skills, because schools have a legal duty to charge for meals.
The appearance of potato smiley faces on the sample menu suggests that processed food has not been entirely removed. But where Jamie Oliver struggled to persuade pupils to eat his healthier meals, Hull has seen an 80 per cent increase in take-up, vindicating the initial investment of pound;1.6 million in the first year.
The "Eat Well, Do Well" scheme has been extended this month to provide free fruit to all primary pupils.