WebMD states that the process of stomach emptying is usually completed within two hours after eating. According to the Prince of Wales Hospital, several factors can alter the average time of stomach emptying, including the type and consistency of food eaten, hormone levels and special conditions, such as pregnancy.
PWH lists liquid foods, protein-rich meals and some drugs, including cisapride, erythromycin and metoclopramide, as some of the reasons for faster-than-average stomach emptying. The factors that inhibit the process include fat-rich food, anxiety, diseases and drugs such as opioids. In severe cases, such as gastroparesis, stomach emptying can be inhibited to the point where it causes nausea, burping and vomiting, according to the Three Rivers Endoscopy Center for Digestive Health and Nutrition.