Fasting for Blood Work: Not if you wish accurate results. Don't have coffee, tea, juice or any sort of fluid apart from water. Do not nibble gum, don't smoke, do not even exercise. Be a monk up until the test is done. As explained by Fasting For Blood Work http://fastingforbloodwork.net/ you can drink coffee as long as there is no sugar involved. But be careful as some black coffee have sugars in them.