There are no stand-alone restaurants or stores on Ko Wai. All meals are taken at the resorts, which generally serve watered-down Thai food to go with commendable attempts at Western fare. As would be expected, prices are fairly steep for what you get.
Paradise's restaurant has the busiest, liveliest atmosphere and is often full of travellers exchanging tips and stories. The breakfasts are decent -- hearty portions of yoghurt with fresh fruit and corn flakes, pancakes, eggs and even French toast with honey. Nescafe is the norm, and the fresh coffee served is not worth the 60 baht price tag. The panang curry we had at Paradise was one of the worst we've ever had, awfully sweet with zero heat despite our request to make it spicy. Next time we'll go for the sandwiches and fries, which looked half decent.
We had a marginally better experience at Good Feeling's smaller restaurant, though it was also nothing to write home about. They focus mainly on Thai food, with some interesting salads available, but don't have much in the way of Western fare. We did not try the food at Pakarang or Grand Mar Hut. We've heard mixed reports about the former, even if the menu fails to inspire, while the latter seems to depend on the mood of the chef.
The restaurants at Pakarang and Good Feeling are open all day, but Paradise closes from 16:00 to 17:00. It's wise to hit the restaurants by 21:00 to ensure you don't go hungry.