Frequently Asked Questions About Diet Coke What is in Diet Coke? Diet Coke is a carbonated beverage that contains carbonated water, caramel color, natural flavors, phosphoric acid, potassium benzoate (to protect taste), artificial sweeteners (aspartame and acesulfame potassium), caffeine, and citric acid. For a more detailed list of ingredients and nutritional information, you can visit the official Diet Coke website. Is Diet Coke calorie-free? Yes, Diet Coke is calorie-free. It is sweetened with artificial sweeteners, mainly aspartame and acesulfame potassium, which provide the sweet taste without adding calories. To learn more about the zero-calorie goodness of Diet Coke, you can…