**5.4 Nutrition**

It is no longer recommended to stop oral intake until the AP has fully resolved and the enzymes have returned to normal limits in order to put the pancreas at rest. Patients ceasing oral intake may develop atrophy in the mucosa of gastrointestinal tract [27, 47, 48, 52, 78, 79], and so oral feeding should be initiated in patients without nausea, vomiting or ileus and with relieved pain, as soon as they can tolerate [47, 48, 52, 79–81]. Liquid, light and low-fat foods should be given at first [82]. In cases of severe AP, enteral feeding may be initiated in patients who are still unable to tolerate oral feeding after 5 days, and in those with complications. For enteral nutrition, a nasojejunal or nasogastric tube should be used for feeding. A nasogastric tube insertion may be easy, but there is a risk of aspiration, while a nasojejunal tube requires an operation. Depending on the conditions, both methods can help provide effective nutrition [47, 48, 82]. If the goal of enteral nutrition is not achieved within 48–72 hours, or if the patient cannot tolerate, parenteral nutrition should be initiated [80, 81, 83].
