Preheat oven to 350 degrees F. Grease a 9x5 inch loaf pan. Lay a strip of parchment down the length of the pan for easy removal. Spray or grease the parchment.
Whisk the flour, baking powder, baking soda, salt, cinnamon and nutmeg together in a large bowl for about 15 seconds.
In a mixing bowl, beat eggs with an electric mixer for 1 minute. Gradually beat in the sugar and beat for another minute. With mixer on low, gradually add the oil and the vanilla. With a heavy duty scraper or rubber spatula, stir in the flour mixture until well-blended. Stir in the carrots, then stir in the nuts.
Transfer batter to the greased pan.
Bake on center rack for about 1 1/2 hours.
Let cool in pan set on a rack for 30 minutes, loosening sides gently after the first 10 minutes. Remove from pan and let cool completely before slicing.