The medical word for delayed stomach emptying is gastroparesis. It is caused by damage to the vagus nerve, which runs from the brain to the stomach, and is linked to both type 1 and type 2 diabetes. Diabetes damages nerves and veins throughout the body, including the vagus nerve in the gastrointestinal system, when blood sugar levels are uncontrolled. Idiopathic gastroparesis is a related illness that has no recognised aetiology. It's treated similarly to gastroparesis caused by diabetes.