Depending on how you the sweetness of your latte to taste like, you can add flavored syrup or flavor shot or you can also add sweeteners too. If there are not syrup or sweeteners added, a medium latte typically contains only a gram of sugar. However, when you add sweeteners and flavored syrup to the latte, the sugar content could go up to about 33 grams. Basically, the amount of sweetness to any Dunkin donut drinks varies on how you customize your drinks.