1. Preheat oven to 325°.
2. Weigh or lightly spoon flours into dry measuring cups; level with a knife. Combine flours and next 4 ingredients (through baking soda) in a large bowl, stirring with a whisk. Combine banana and next 4 ingredients (through oil) in a small bowl. Add banana mixture to flour mixture, stirring just until moist.
3. Spoon the batter into a 9 x 5–inch loaf pan coated with cooking spray. Bake at 325° for 1 hour and 15 minutes or until a wooden pick inserted into the center comes out clean. Cool for 10 minutes in pan on a wire rack, and remove from pan. Cool on wire rack.