All food is included inprice of cruise, you only have to pay for drinks, unless you can upgrade to all inclusive, but that usually is only on thomson cruise.
In La luna and the bistro you have to pay (service restaurants) and in waterfront and plantation all food is included (buffet service.
On Ocean Village and Ocean Village Two, all food in the self-service restaurants is included, plus on deck BBQs and some items in La Luna at a lunchtime. You pay a supplement to eat in the Bistro and La Luna in the evenings, and a supplement for some lunchtime food in La Luna. You also have to pay for cakes and snacks at Charlies Bar. All is explained in the brochure and on the Ocean Village website.