There was a time many years ago when eggs, fats, and oils were thought to be no-nos, so I'd omit or replace them every time I baked. I used applesauce instead of oil, a mashed banana instead of an egg, and margarine instead of butter. I also used fat-free yogurt instead of cream, and reduced-fat peanut-butter to make cookies.
The food came out, well, OK, but I think I ended up eating more just because I thought it was healthier. Now I mostly follow the recipe pretty much to a T. It tastes so much better, so only a few bites are necessary.
What about you? Do you cut out ingredients or use healthier alternatives when cooking or baking?