As you might guess, there is no standard amount. People in the USA generally add whatever tastes best to them, which can range from none to very creamy and sweet. However, that being said, you can probably work with some averages if you like. In fast-food restaurants, coffee creamer comes in containers of 0.5 ounces (15 mL), and most people use just one or two. Similarly, sugar comes in packets of 1 teaspoon (4 grams), and people typically use one or two. So I would say you can justify using either 15 or 30 mL of cream/milk and 4g or 8g of sugar in an 8 ounce (approx. 250 mL) cup of coffee.

Dear Dr. Greg,

Thank you. I will try these amount.

WHAT is the emperical quantity of sugar in coffee, sucrose / glucose trace content, also the  lactose or coffee trace milk constitution . these could help you adjuncts the amaount of sugar for coffe.also metabolizability of targets.

I have the same opinion with Ogori AKAMA.