For most public school students in New York City, the old adage holds true: There’s no such thing as a free lunch. But a coalition of labor unions including the UFT, food advocates, elected officials and educators is calling on Mayor Bill de Blasio to change that.

The group gathered on the City Hall steps on Nov. 16 for a press conference asking the mayor to make good on his campaign promise to fund free school lunch for all of the city’s 1.1 million public school children. Advocates contend that the income requirement for free lunch now creates a stigma, forcing many children to choose between feeling ashamed or going hungry.

“Kids do better in school when they eat,” said UFT Vice President for Middle Schools Richard Mantell. “Every student should get lunch.”

Currently, 76.5 percent of city students qualify for free or reduced-price lunch based on household income. A free lunch program implemented in stand-alone middle schools in 2014 resulted in thousands of additional students participating. The Lunch4Learning campaign estimates an additional 47,000 children would get lunch if the program became universal.

“The middle school program is a proven success,” said Liz Accles, the executive director of Community Food Advocates who has spearheaded the Lunch 4 Learning campaign. “If addressing income inequality and education equity are truly the mayor’s chief priorities, he must expand this program to all children, in all schools, now.”

According to Lunch 4 Learning, every student could have equal access to free daily lunch for little more than a dollar per student, per school day, since the federal and state governments would pick up 92 percent of the total lunch costs.

In his campaign for mayor in 2013, de Blasio said, “I think we’re missing an opportunity to use available federal funding to make school lunches free, and I think we have to end any stigma around school lunches and universalize it — it’s crucial.”

The advocates estimate a universal lunch program would cost the city about $8.5 million on top of the $11.2 million it already spends on free lunches in middle school.

In the context of the city’s overall $82.2 billion budget, Council Member Julissa Ferreras-Copeland said, “We can cover the cost of this.”