Syrups are the biggest contributor. Each pump of a standard flavored syrup adds a fixed amount of sugar, and the number of pumps grows with the cup size.

Sauces such as mocha, white mocha and caramel are denser than syrups. They add sugar and fat, which is why chocolate-based drinks often top the sugar charts.

To see the effect of each change, a starbucks calorie calculator shows sugar alongside calories as you adjust the size, milk, pumps and toppings.

The simplest way to lower sugar is to reduce pumps. Many people can drop to half the default and still enjoy the drink.