I feel that unlike a lot of possible food types, rice would offer a unique niche in that it's largely a water-based plant. So here's my take:
Rice grows on lily pads (giving lily pads a functional use beyond occupying water space, and making it the only plant that doesn't require dirt or farmland to grow), and grows at a faster rate than wheat. When it reaches its mature state, you can harvest it for two to five rice grains and a couple rice seeds. Breaking it prematurely will only yield a seed.
Rice grains can be eaten individually (for a very low value, only half a hunger bar each), but three of them can be combined together with a bowl to create a food that grants two and a half hunger bars. You can take this one step further and cook the rice bowl, improving the nutritional value to three and a half hunger bars.