cook the best healthy muffins ever

By healthy, I mean low-calorie, filling. Low in fat/carbs would be good too. So far I’ve made some pretty good Morning Glory muffins (apple, cinnamon, raisins, carrots…), banana muffins, and some horrendous strawberry muffins. i’ve been substituting some of the flour with wheat flour, which definately makes a difference in the flavor. Too much wheat flour can be overpowering, so there is a delicate balance to master.