The flavor and texture of pound cake will be affected by any changes in ingredients, so you’ll want to bake a practice cake before springing your experiment on unsuspecting guests! That being said, unsweetened applesauce is a low-calorie substitute that adds fiber and moistness; use half the amount applesauce. Similarly, some people use buttermilk or Greek yogurt at half the recommended amount of butter. You can also use vegetable oil in the amount of ¾ cup oil to each full cup of butter. For an extra nutritious substitute, use an equal amount of pureed avocado (aguacate) or ¾ cup of pureed pumpkin or squash rather than a cup of butter.