Ask for a gastric empty test.Nausea, no appetite, and losing weight are 3 symptoms of Gastroparesis. I had one done and 70% of food was still left in my stomach after 4 hours. That is severe gastroparesis. Gastroparesis is a chronic disorder where the stomach takes too long to empty its contents into the small intestine due to weak stomach muscles or nerves. It will cause nausea, vomiting, feeling full after a few bites, abdominal pain, bloating, heartburn, and loss of appetite and weight loss due to malnutrition..I hope this help a little. Good luck..