Black coffee has 2 calories per 8oz cup, according to USDA FoodData Central. That's it — less than a stick of gum. But the moment you start adding milk, sugar, cream, or flavored syrups, those 2 calories can balloon to 400+ without you noticing.
The coffee itself isn't the problem. It's what goes into it. Here's exactly how many calories are in every type of coffee, from a plain black cup to a Starbucks Frappuccino.