Preheat the oven to 350°F (175°C). Grease a 9x5-inch loaf pan.
In a medium bowl, whisk together the flour, baking soda, salt, cinnamon, and nutmeg.
In a large bowl, mix the granulated sugar, brown sugar, and vegetable oil until well combined.
Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
Gradually add the dry ingredients to the wet mixture, stirring until just combined.
Fold in the chopped rhubarb and nuts (if using) until evenly distributed.
Pour the batter into the prepared loaf pan and smooth the top.
Bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
Allow the bread to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.