A full stomach after eating less than usual isn’t normal. It might be because of an ulcer or GERD (gastroesophageal reflux disease). If you’ve had diabetes for more than 10 years, you could have gastroparesis. That’s when your stomach doesn’t empty as fast as it should. There could be a more serious cause, but that’s rare. Some cancers -- ovarian, stomach, or pancreatic -- can make you feel full fast, even though you didn’t eat a lot.