Hi Sandy, since any leavening power provided by the sourdough discard will be related to its acidity reacting with the baking soda, I would not recommend reducing the baking powder and baking soda in this recipe. Our normal recommendation when adding sourdough discard to a recipe is to reduce the flour and liquid amounts equally to add up to the amount of discard you'd like to add to the recipe. This is a little tricky with banana bread, since the liquid is just mashed banana, but you could reduce this by 30g, along with 30g of flour, to equal the 60g of discard you would like to add to this recipe. Or you might just want to try our Sourdough Banana Bread recipe and substitute 1 cup (113g) of White Whole Wheat flour for one of the cups of Unbleached All-Purpose flour. 

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