i found this recipe from bostons flour bakery in a runners world article. i dont like using refined sugar so i replaced 1 cup sugar with 3/4 cup of fruit concentrate along with the low fat modification listed below. it lost a bit, too light. i should have isolated the changes.

1 2/3 cups all-purpose flour
1 teaspoon baking soda
1/4 teaspoon ground cinnamon
1/2 teaspoon salt
1 cup sugar, plus 2 tablespoons sugar
2 eggs
1/2 cup vegetable oil
3 1/2 bananas, very ripe, mashed
2 tablespoons low-fat sour cream
1 teaspoon vanilla
2/3 cup walnuts, toasted and chopped

Preheat oven to 350°F. Sift together first four ingredients. Beat
sugar and eggs with a whisk until light and fluffy. Drizzle in oil. Add
bananas, sour cream, and vanilla. Fold in flour mixture and nuts. Pour
batter into a buttered 9″ x 4″ loaf pan and bake for 45 minutes, or
until a toothpick inserted in the center comes out clean. Makes 12
servings. Lower-fat version: Reduce oil to 1/4 cup, add 1/4 cup
unsweetened applesauce (260 calories, 9 grams of fat).

Calories: 310
Fat: 15 g
Carbs: 41 g
Protein: 4 g