At Malone Integrated College about 55% of pupils have free school meal entitlement and there are also a lot of parents who are on lower incomes.
When the prices of school meals increased earlier this year, Leslie said she remembers “sitting with the head of the cafeteria and heartbreakingly decide how much to put up each item”.
“I think the cumulative effect of this will be immense, particularly families who have multiple children, both at a primary school and a post-primary school, and trying to make ends meet, it’s going to become incredibly difficult,” Leslie told BBC News NI.
“I can’t imagine what it would be like for families trying to budget that moving forward, as well as planning for Christmas.
“I firmly believe families are going to struggle at Malone.
“I do believe that there will be some families and some young people who will be worried about the stigma attached to this, and won’t voice their concerns and won’t ask for help. And as an integrated school, that’s really sad for us.
She added: “I think it’s going to be quite cutthroat for families.
“Already, we have some of our children, particularly in junior school talking about Christmas and how they’ve had discussions with their families that things are going to be much more scaled down this Christmas, just with the general cost of living crisis.
“And then this is only going to amplify the situation even more for young people.”
Leslie added that not having a healthy, balanced diet or going without food will be a “barrier to learning”.
