3. It may upset your stomach.
While your beloved beverage will help you to wake up in the morning, it may also give you the urge to use the bathroom more often. In fact, some medical experts even recommend drinking coffee as a way to prepare for certain exams. Coffee activates our nervous system, which in turn affects the colon and may cause diarrhea. Many people also like adding milk or cream to their morning cup of java, and because most of us have difficulty digesting lactose, it may cause stomach discomfort as well.