Heat oven to 175C. Grease the bottom of a 9×5 loaf pan.
In a large bowl, mix Lite&Sweet and butter. Add eggs, mashed bananas, buttermilk, and vanilla. Mix well on medium speed until smooth. Stir in flour, baking soda, baking powder, salt, and nuts until moistened. Pour batter into pan.
Bake for 55-60 minutes, or until a toothpick inserted into the center of the loaf comes out clean. Allow to cool for 10 minutes. Loosen sides of loaf from pan. Remove from pan and place on cooling rack.