Eating in the Yasawas is largely a matter of where you are staying. There are no standalone restaurants, no beachside cafes, and no village shops selling prepared food. The islands have no towns — accommodation operators, whether resort or village bure, provide all meals, and in most cases eating is included in the room rate.
Resort meals tend toward a Fijian-Pacific hybrid: fresh fish and shellfish are the staples, cooked simply or in a lovo (the traditional underground oven lined with hot stones). Coconut cream features heavily — in fish curries, in taro dishes, in the desserts made from ripe pawpaw. The lobster served at most mid-range and upmarket resorts is the Yasawa spiny lobster, caught by local fishermen the same day, and it is reliably excellent. Budget bures put on whatever the household is cooking: root vegetables (taro, cassava, breadfruit), rice, tinned fish when fresh isn't available, and a great deal of tea.
If you are staying in a village guesthouse, eating with the household is part of the arrangement — and eating with them rather than at a separate table is the version worth choosing. Accept what's offered, eat with your hands if that's how everyone else is eating, and ask about the dishes. The conversation that follows is usually more interesting than the food, which is plain but wholesome.
Bring your own supply of snacks, coffee, and anything you cannot do without from the mainland — once you board the Yasawa Flyer, you are committed to what your island has available.