Oil a loaf pan, or line it with parchment paper. Preheat the oven to 325°F (163°C).
Shred zucchini until you have 2 cups (300g) of it. (Alternatively, see the easy blender instructions in the notes below.)
Combine the flours, baking soda and powder, cinnamon, and salt with a whisk in a medium-sized mixing bowl.
In small bowl, whisk together the eggs, oil, and syrup.
Stir the wet ingredients from the small bowl into the dry ingredients in the larger bowl.
Stir in the shredded zucchini and the nuts or chocolate chips, if you're using them.
Pour the batter into your prepared loaf pan. Bake it for about 50 minutes, or until the centre tests 200°F (93°C) with a thermometer.
Allow the loaf to cool in the pan on a cooling rack for 10 minutes, before you remove it. Then let it continue to cool to room temperature before slicing it.
Easy Blender Method: Rather than shredding the zucchini, you might find it easier to use a blender. Simply combine the liquids (oil, syrup, and eggs) in a blender. Add 300 g zucchini chunks, and process until smooth. Then proceed to mix this liquid with your dry flour mixture, and follow the recipe instructions from there.