The coconut provides a high amount of fiber (75% of the carbs in coconut are fiber!- coconut fiber has been shown to control blood sugar especially well), as well as some healthy fats (medium-chain fatty acids, including lauric acid). Read an article here, or a website on coconut research here.
The egg white helps bind it, and contributes protein.
The honey, of course, sweetens it, as well as helping moisten and bind.
Here's what I ended up with after a couple experiments:
2 egg whites
1/2 c. honey
3 cups unsweetened, fine-flake coconut
Preheat the oven to 350 degrees. Line a baking sheet with parchment, or grease it. Beat the egg whites until just foamy, then whisk in the honey. Stir in the coconut until well mixed. If it won't hold its shape yet, let it sit for 15-30 minutes to let the moisture absorb into the coconut.
Use 1/4 cup packed (1.7 oz prebaked weight) for 1 1/2 oz macaroons, or a scant 1/3 c. scoop for 2 oz (2.2 oz. prebaked weight), bake 17-18 minutes, until just turning brown on the tops. Let cookies cool on the baking sheet for 5-10 minutes before you take them off; otherwise they'll fall apart.
This makes 12 (1 1/2 ounce) macaroons, or 9-10 (2 ounce) ones.