School districts across the U.S. have been making upgrades in recent years to try and entice children into healthier eating habits amid higher nutrition standards that emphasize whole grains, fruit and vegetables.

But for many, funding these improvements has been a challenge as heavy demand for limited amount of means schools increasingly must pay for them on their own.

Some districts turned to their limited budgets for gradual improvements, while others have passed the bulk of the multimillion-dollar tabs to through bond packages.

The Dallas Independent School District has used a variety of methods to fund improvements for dozens of kitchens, including a bond program, a federal grant and millions from its own budget. But another 20 school kitchens are in line with no funding in sight.