Dumping Syndrome is something that often afflicts patients after gastric bypass surgery, or stomach surgeries. Your body moves food along too fast, and it winds up in your small intestine before it should have. It often causes rapid heartbeat, feelings of anxiety, feeling lightheaded, dizziness, nausea, diarrhea, and vomiting. You can treat it simply by eating low carbohydrate food, cutting out pop and sugars, and eating more healthy. Lying down after eating is also a good idea, as it can slow the digestion, and keep the food from rushing so fast.