Preheat the oven to 350°F (175°C). Grease and flour a 9×5-inch loaf pan.
In a medium bowl, whisk together the flour, baking soda, baking powder, salt, cinnamon, and nutmeg.
In a large bowl, beat the brown sugar, vegetable oil, eggs, and vanilla extract until well combined.
Stir the dry ingredients into the wet ingredients until just combined.
Fold in the grated zucchini until evenly distributed.
Pour the batter into the prepared loaf pan and smooth the top with a spatula.
Bake for 55 to 60 minutes, or until a toothpick inserted into the center comes out clean.
Remove the bread from the oven and allow it to cool in the pan for 10 minutes.
Transfer the bread to a wire rack to cool completely before slicing.