Preheat oven to 375°F. Coat 2, 9×5 pans with nonstick spay. Set aside.
In a large bowl stir together the sugar, oil, eggs, vanilla, cinnamon, salt, baking soda, and baking powder until smooth.
Next stir in both flours until just combined. Finally stir in the zucchini, carrots, banana, and walnuts until combined.
Divide the batter between the 2 pans.
Bake for 50-60 minutes or until a toothpick inserted into the center comes out clean.
Allow to cool in the pan for 5-10 minutes
Adapted from Cookies and Cups.