Whisk flour, white sugar, brown sugar, cinnamon, baking powder, and salt together in a bowl until no lumps remain.
Pour milk, vegetable oil, and vanilla extract into the flour mixture; stir until just combined.
Beat egg whites until foamy in a large glass or metal mixing bowl until soft peaks form. Lift your beater or whisk straight up: the egg whites will form soft mounds rather than a sharp peak.
Fold the the beaten egg whites into the batter.
Preheat a waffle iron and coat with cooking spray.
Pour batter onto waffle iron in batches and cook until crisp and golden brown, about 2 minutes; repeat until all batter is used.