Preheat oven to 350 degrees. Prepare a loaf pan by spraying/wiping with a touch of oil, and lining with a strip of parchment paper (for easy removal after cooling).
In a large bowl, add dry ingredients: flour, cocoa powder, coconut sugar, baking powder, baking soda, and salt. Stir through until well combined.
Add zucchini, bananas, maple syrup and hemp seeds (if using) to a blender. Puree until smooth (this takes just a minute in a high speed blender, a regular blender will take longer). Once well pureed, add water and vanilla and blend again.
Add wet mixture to dry and stir through until just well combined, and add chocolate chips if using. Transfer mixture to loaf pan.
Bake for 50 minutes, or until set in the center (test with a toothpick if unsure). Remove and let cool in the pan on a cooling rack. Once cool, remove loaf and cut into slices.