(Reuters) – Thousands of U.S. public school districts are teaming up with local farmers to put more fresh fruits and vegetables on lunchroom menus, without breaking budgets or getting any help from celebrity chefs.

The schools are taking early steps toward adding more fresh and homemade foods as advocated by British chef Jamie Oliver, who led a campaign to improve school lunch in his country. But inexpensive, processed foods still dominate U.S. school menus.

Proponents including U.S. President Barack Obama are pushing for a bigger investment in school meals that feed some of the country’s neediest children. The aim is to establish healthier eating habits and curb obesity rates that are driving nearly $150 billion in medical costs each year.

Nearly a third of U.S. children are obese or overweight and public health experts are warning that this generation of youth may be the first to live shorter lives than their parents.