1Heat oven to 350°F. Grease bottom only of 8x4-inch or 9x5-inch loaf pan with shortening, or spray with cooking spray. In medium bowl, mix flour, baking powder, baking soda, salt and cinnamon.
2In large bowl, beat sugar, oil, egg whites, bananas, milk and vanilla with spoon until well blended. Stir in flour mixture until well blended. Stir in walnuts. Spoon into pan.
3Bake 8-inch loaf 55 to 62 minutes, 9-inch loaf 45 to 52 minutes, or until toothpick inserted in center comes out clean. Cool 5 minutes; remove from pan to cooling rack. Cool completely, about 1 hour, before slicing.