"I broke up with cheese," Vardalos recently told PEOPLE. "I always say like cheese keeps calling me and trying to get me to meet at a cheap motel but I'm really committed to just staying single for awhile."
Although Vardalos says that she did "like 50 other things" to lose the weight, she claims that eliminating cheese from her diet "was the thing that changed my life."
Vardalos, who calls her weight loss a "crazy thing," was at the festival to screen her new movie, My Life in Ruins. The film hits theaters June 5.
Reporting by JENNY SUNDEL