There is now evidence that even short-term hyperglycemia may cause problems in the GI tract. Normally, your stomach's slow, steady, muscular contractions mulch solid food into tiny particles. Then your stomach pushes liquids and solids into your small bowel. If you have gastroparesis, this powerful grinding function of the stomach is greatly reduced or lost. Food can't be broken up into smaller pieces and doesn't move into the small bowel normally.
Food stays in the stomach much longer than normal.
The most disturbing symptoms are nausea and vomiting. When you can't stop vomiting, you may get dehydrated. That, in turn, can lead to diabetic ketoacidosis. Persistent vomiting can also make the lining of your stomach bleed. Typically, vomiting occurs after meals.