A 12-ounce can of Diet Coke contains no sugar. The sweetener used in Diet Coke is aspartame, which is 200 times sweeter than sugar. Aspartame is regulated by the Food and Drug Administration.
According to Calorieking.com, a 12-ounce can of regular Coca-Cola contains 39 grams of sugar. This is the equivalent of 10 teaspoons of sugar per can. The sweetener that is used in regular Coca-Cola is high fructose corn syrup, which is composed of glucose and fructose. Common table sugar is sucrose, which is typically sourced from sugar cane or beets. HFCS is made out of yellow dent corn.