Preheat oven to 350F degrees. Combine sugar, pumpkin, oil, pudding and egg whites in a large bowl, stirring well with a whisk. Combine flour, cinnamon, salt and baking soda in a medium bowl, stirring well with a whisk. Add flour mixture to pumpkin mixture, stirring just until moist. Stir in chocolate chunks.
Spoon batter into 2 (8-by-4-inch) loaf pans coated with non-stick cooking spray. Bake for 1 hour and 15 minutes or until a toothpick inserted in the center comes out clean. Cool 10 minutes in pans on a wire rack and remove from pans. Cool completely on wire rack before slicing and enjoying.