Preheat oven to 350F. Spray a 9 x 5 inch loaf pan with baking spray.
Dry Ingredients: In a medium bowl, combine flour, sugar, baking soda, pumpkin spice, nutmeg, cinnamon, and salt with a wire whisk. Set aside.
Wet Ingredients: In a large bowl mix oil, egg whites, pumpkin puree and vanilla; beat at medium speed until thick. Scrape down sides of the bowl.
Add flour mixture (dry ingredients), then blend at low speed until just combined. Do not over mix.
Pour batter into loaf pan, top with pepitas and bake on the center rack for 50-65 minutes, or until a toothpick inserted in the center comes out clean.
Let the pan cool at least 20 minutes, bread should be room temperature before slicing.