Regular black coffee (without milk or cream) is low in calories. In fact, a typical cup of black coffee only contains around 2 calories. However, adding cream or sugar will increase the calorific value.
Coffee beans also contain polyphenols, a type of antioxidant.
Antioxidants can help rid the body of free radicals, a type of waste product that the body naturally produces as a result of certain processes.
Free radicals are toxic and may cause inflammation. Scientists have found links between inflammation and various aspects of metabolic syndrome, including type 2 diabetes and obesity.