If you remove all sugar, the cake will end up dry, rubbery, and small. Besides sweetness, sugar also provides moisture, volume and a nice brown color after baking, so you must replace it with an efficient alternative, such as fruit purees (e.g. applesauce) or high-intensity sweeteners, which keep the cake soft and tender. Adjustments to liquids, fats and leavening are often needed to preserve texture and volume.