Whisk together and then sift (it's important that these ingredients be thoroughly combined) the baking soda, baking powder, salt, cinnamon, nutmeg and flour. Add all at once to the banana mixture. Mix quickly but thoroughly then stir in the yogurt and nuts, mixing until just combined.
Pour the batter into a greased and floured 9x5 inch loaf pan. Bake at 350 for about one hour or until a toothpick inserted comes out clean.
If the bread begins to brown to quickly, tent it with aluminum foil after 40 minutes in the oven.