"The primary concern about eating before surgery is that general anesthesia causes nausea and vomiting. If the patient vomits while being anesthetized, there is a risk that the vomit could be aspirated into the lungs. This can be extremely dangerous and sometimes fatal if not addressed. During the procedure, vomiting or stomach reactions could also interfere with the anesthesiologist's equipment or the surgical site. Once the patient wakes up, he or she will feel nauseous and will be offered clear liquids and plain foods to help reduce the feeling of sickness."