The new service is being offered by catering firm Sodexho, which has won a pound;1.2 million contract to serve food to 7,750 children at eight of the city's secondaries.
Its research showed half of all children do not eat school lunches and prefer to snack instead. The proposed menu will include buns,milkshakes, fruit juice, vegetarian food and sandwiches.
Since April, schools have been able to choose hw they spend their budgets on meals. Previously the council's catering service supplied meals to all its secondaries. Sodexho now shares the supply of school meals with the council service and a local catering firm.
Sodexho, one of the UK's largest catering companies, provides meals at more than 180 independent schools, 70 colleges and universities and 650 state schools.
Helen Lynch, head of Nab Wood upper school, called the scheme "interesting" and said it would reduce queues.