Most people use 6-inch tortillas for tacos, but we apply healthy new math and use them for quesadillas. Upsizing to an 8-inch tortilla nearly doubles the surface area, meaning twice as much cheesy filling. Suddenly, your sensible meal becomes an 800-calorie heavyweight. Start with a 6-incher, and pile on the lean meats, veggies, and cheese. Crisp in a hot skillet with cooking spray instead of butter to save 7g sat fat.