Carrots give carrot cake a health-halo effect—people think it's health food, but it's usually very high in fat and calories. But our version has about 40 percent less calories and 50 percent less fat than most. First, we use less oil in our batter. Then we skip the butter in the frosting (don't worry, it's still light and smooth). To ensure the cake is moist, we add nonfat buttermilk and crushed pineapple.