Preheat oven to 325 degrees Fahrenheit. Line a muffin tin with paper liners and set aside.

In a large bowl, whisk together flours, baking powder, baking soda, and salt.

In a medium bowl, mix the sugar or honey, egg and egg whites, oil, and yogurt.

Add the wet ingredients to the dry ingredients, along with the zucchini and walnuts. Stir to combine.

Fill muffin tins about two-thirds full and bake 25–30 minutes, or until a toothpick inserted in the center comes out clean. Let cool on a rack.