Causes of stomach gas include drinking carbonated beverages, eating fatty foods, eating quickly and smoking, according to Mayo Clinic. Stress and anxiety may also contribute to gas in the stomach.
Stomach gas can be caused by a blockage, disease or infection in the gastrointestinal system, states Mayo Clinic. Stomach gas can also be caused by irritable bowel syndrome, or IBS; or conditions that cause the intestines to be unable to process certain food ingredients, such as lactose intolerance or celiac disease. Eating too much fatty food can cause an uncomfortable feeling of being full, and it delays the emptying of the stomach, which can cause stomach gas.
Sometimes stomach gas is caused by swallowing air, notes Mayo Clinic. Some common ways people accidentally swallow air include chewing gum, sucking on candies, smoking or drinking through a straw. People with gastroesophageal reflux disease or acid reflux may swallow air when they try to swallow backed-up stomach acid in the esophagus. For this reason, treating heartburn may lead to a reduction in stomach gas. Eating and drinking slowly may reduce stomach gas by decreasing the amount of air swallowed while eating.
Foods that contain carbohydrates may cause stomach gas, explains Mayo Clinic. Some gas-inducing foods include whole grains, onions, lettuce and milk products. Other foods that may cause stomach gas include cabbage, cauliflower, beans and peaches.