Preheat your oven to 350°F (175°C).
Spray a 9x5 inch loaf pan with cooking spray or lightly grease it with oil.
In a large mixing bowl, whisk together the all-purpose flour, nonfat milk powder, collagen peptides, cinnamon, nutmeg, baking powder, baking soda, and both salts until well combined.
In another bowl, mash your ripe bananas until smooth. Add in the Truvia, granulated sugar, vegetable oil, egg whites, vanilla extract, and Greek yogurt. Mix until everything is well incorporated.
Gradually add the dry ingredients into the wet mixture, stirring gently with a spatula until just combined.
Pour the batter into your prepared loaf pan and smooth the top with the spatula. Bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
Once baked, remove the banana bread from the oven and let it cool in the pan for about 10 minutes. Then, turn it out onto a wire rack to cool completely before slicing.