Preheat oven to 350º.
Lightly spray a standard muffin pan with cooking spray.
In a medium bowl, stir together flour, baking powder, baking soda, cinnamon, and salt.
In a large bowl, stir together egg whites, mashed banana, yogurt, sugar, and oil.
Gradually stir the flour mixture into the banana mixture, just until moistened.
Then, fold in the chocolate chips and pour batter into the muffin pan.
Bake for 45-50 minutes, or until a toothpick comes out clean from the middle of a muffin.