Most people know that beans, broccoli, and onions can cause gas, but what most people don't suspect are fruits, sodas, and milk. Fructose (a sugar found in fruits and sodas) and lactose (a sugar found in dairy products) are common causes of gas, bloating, abdominal cramps, and diarrhea. Lactose intolerance is extremely common. It is estimated that 30 to 50 million Americans have some degree of lactose intolerance.