Final answer:
The most common complication of bariatric surgery is dumping syndrome.
Step-by-step explanation:
The most common complication of bariatric surgery is dumping syndrome. Dumping syndrome occurs when the stomach empties too quickly after eating, causing symptoms such as nausea, vomiting, abdominal cramps, and diarrhea. It is more likely to occur after procedures like gastric bypass or sleeve gastrectomy.