Preheat the oven to 375°F and line a baking sheet with parchment paper.
In a large bowl, combine the ground beef, breadcrumbs, egg, diced onion, minced garlic, salt, and black pepper. Mix until just blended, then shape into a loaf and place on the prepared sheet.
Bake the meatloaf for 45 minutes. While it bakes, stir together the brown sugar, pineapple juice, and ketchup in a small bowl to make the glaze.
Remove the meatloaf from the oven and brush the glaze evenly over the top. Return it to the oven for 15 more minutes until the glaze sets and the internal temperature reaches 160°F.
Meanwhile, rinse the rice under cold water. In a saucepan, combine the rice, coconut milk, water, and pinch of salt. Bring to a boil, then reduce to low, cover, and simmer for 18 minutes until the liquid is absorbed. Fluff with a fork before serving.
Slice the meatloaf and serve over the coconut rice.