Preheat the oven to 350°F (175°C). Grease and flour a 9×5 inch loaf pan.
Grate the zucchini using a box grater. Place the grated zucchini in a clean kitchen towel and squeeze out excess moisture. Set aside.
In a medium bowl, whisk together the all-purpose flour, baking soda, baking powder, salt, ground cinnamon, and ground nutmeg.
In a large bowl, beat the granulated sugar, light brown sugar, and eggs together until smooth and creamy.
Add the vegetable oil, buttermilk, and vanilla extract to the sugar and egg mixture. Mix until combined.
Gradually add the dry ingredients to the wet ingredients, stirring gently until just combined. Do not overmix.
Fold in the grated zucchini until evenly distributed.
Pour the batter into the prepared loaf pan and spread it evenly.
Bake in the preheated oven for 50 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 and let it cool completely before slicing.