Black coffee can affect your blood sugar, causing it to rise. For some people, mainly diabetics, this can be a real problem. Controlling your blood sugar may mean you have to cut down on coffee intake. read more
The average U.S. adult consumes about two 8-ounce cups (474 milliliters) of coffee a day, which can contain around 280 milligrams of caffeine. For most young, healthy adults, caffeine doesn't appear to noticeably affect blood sugar (glucose) levels, and consumption up to 400 milligrams a day appears to be safe. read more