A fat-busting cooking tip

I love to bake, but I don't like the calories.  So when I bake, I often substitute the oil in a recipe with unsweetened applesauce.  (And just WHY would anyone WANT to sweeten applesauce?  It's already sweet!!!)

For Christmas, I baked a very rich carrot cake.  Because it was the first time I used that recipe, I decided to make it as directed--with a full cup of oil.  It was pretty darn good.  For Valentine's Day, I made the same cake, only this time I substituted the oil with applesauce.

How did it turn out?

Pretty good.  A bit moister, but other than that it was still a very good cake.

I noticed that my local grocery store is now selling a prune mixture, which can be used as a substitute for oil, and I'm going to buy some and try that in a recipe some time soon.  (While I contemplate going on a diet and putting all baking on hold for some time.)

What ingredient have you substituted in a recipe?