In a bowl, sift together flour, baking soda, baking powder and spices.
In a separate bowl, whisk eggs. Add oil. Stir in sugar. Stir in grated zucchini.
Mix together the mixtures in the 2 bowls. Add chopped walnuts and mix together well.
Spoon into 2 greased bread pans. Bake in a preheated 350°F oven for 1 hour, or until inserted toothpick comes out clean.