Preheat the oven to 350°F (175°C) and grease a loaf pan.

In a mixing bowl, combine the mashed bananas, vegetable oil, eggs, and vanilla extract. Mix until well combined.

In another bowl, whisk together the flour, brown sugar, granulated sugar, baking soda, baking powder, salt, cinnamon, and nutmeg.

Gradually add the dry ingredients to the wet ingredients, stirring until just combined.

Fold in the grated carrots, walnuts, and raisins until evenly distributed.

Pour the batter into the prepared loaf pan and smooth the top.

Bake in the preheated oven for 55-60 minutes, or until a toothpick inserted in the center comes out clean.

Allow the bread to cool in the pan for 10 minutes before transferring to a wire rack to cool completely.