Parents were being encouraged to leave high sugar foods out of their children's lunchboxes for at least the month, but Ms Thomas had hopes it would continue beyond June.
"I think it will be really hard but just getting the information out there is a good start, I'm not expecting miraculous changes but little changes help," she said.
By encouraging parents to get involved Ms Thomas hoped they would make better choices about what went into their kids' lunchboxes every day.
Ms Thomas had already posted several healthy recipes and ideas on Storypark, an online forum for parents to view their child's educational progress.
The nationwide campaign is a fundraiser for the Cancer Society of New Zealand.
Supporters are asked to raise money for the cause by being sponsored by friends and family to make it through the month junk-free.
However, Ms Thomas said since the daycare operated in a low socio-economic area they were just doing it for the health benefits.
"We're just getting parents aware of what's going into their kids' bodies and how it can affect them in the long-run."