In a large bowl, whisk together flours, baking powder, salt and cinnamon. Set aside.
In a separate bowl, whisk together sweet potato, milk, orange juice, brown sugar, coconut oil and vanilla. Add to the flour mixture and stir to combine. The batter will be very thick.
In a clean, dry bowl, beat egg whites with an electric mixer on low speed until foamy, then increase speed to high and beat until stiff peaks form. Gradually fold egg whites into the sweet potato batter 1/3 at a time.
Ladle or scoop batter onto a preheated, greased waffle iron, sprinkle evenly with a small amount of the chopped pecans and cook until lightly browned (exact cooking time will vary depending on your waffle iron). Keep cooked waffles warm on a cookie sheet in a 200-degree oven. Serve with maple syrup and love.
Leftover waffles can be frozen and reheated in the toaster (I like to microwave mine for 20-30 seconds just to take the chill off of them before putting them in the toaster.)