Preheat the oven to 350 F and grease a 9x5 inch loaf pan, then line it with parchment paper leaving an overhang on the long sides.
Grate the zucchini on the large holes of a box grater. Squeeze it gently in a clean towel to remove some, but not all, of the moisture.
In a medium bowl, whisk together the flour, baking soda, baking powder, salt, cinnamon and nutmeg.
In a large bowl, whisk the vegetable oil, granulated sugar, brown sugar, yogurt and vanilla until smooth and glossy. Stir in the grated zucchini.
Add the dry ingredients to the wet mixture and fold just until no dry streaks remain. Fold in the chopped walnuts. The batter will be thick.
Scrape into the loaf pan and bake for 50 to 55 minutes until a toothpick inserted in the center comes out with a few moist crumbs. Cool in the pan for 15 minutes, then lift out and cool completely before slicing.
