The island's "whole foods" equivalent is called Papaya's Natural Foods. It has everything you could need and more to live and eat well during your stay. There are a few on the island, but one is conveniently located across the road from Sweet Marie's for a quick double trip.
We also ate at a unique restaurant called Bar Acuda. It was a Spanish inspired dining experience. We were served small beautifully and artistically displayed dishes. It was a bit pricey, but worth it for the unique experience.
As recently obsessed coconut eaters, we were excited to try a fresh Hawaiian coconut. Sadly, it was not anywhere near tasty. It was a fermented old coconut. We should have known better. We'll stick to our fresh young Thai coconuts from now on!