How to Make a Cake Mix Low-Fat. Even though you cannot change the ingredients of cake mix you buy in a store, you can follow these steps to turn the mix into a low-fat, delicious cake.
Use egg whites instead of whole eggs. If a cake mix recipe calls for three eggs, use four egg whites instead. This will eliminate the yolk, which is where a lot of the fat content of an egg is contained.
Substitute applesauce for cooking oil. It seems strange, but for baked goods it works. Use the same amount of applesauce that you would of oil. It can also make the cake fluffier, but it may result in the cake going bad quicker.
Try out nonfat plain yogurt instead of oil. If the applesauce solution does not seem right for you, try using yogurt to reduce some of the fat.
Add 2 percent or skim milk to your cake mix instead of using whole milk.
Sweeten your mix with sugar substitutes instead of sugar. Many cake mixes will already have the sugar in it, but if you need to add sugar, try using a sugar substitute that works for baking like Splenda. Not all sugar substitutes will work well with baking or they may work in lesser amounts, so be sure to check before you use a sugar substitute.
Spray your cake pan with nonfat cooking spray instead of using butter or oil. It may not seem like much but it will help cut down on a little extra fat.