Most people produce between 1 and 4 pts. of gas per day and pass gas an average of 14 times per day, according to the National Digestive Diseases Information Clearinghouse. This gas comes from swallowed air and the breakdown of undigested foods by bacteria in the gastrointestinal tract. Some foods cause more gas than others, because they are poorly digested and thus reach the large intestine in larger quantities. If this gas does not pass easily through either belching or flatulence, bloating will occur.
Sugars
Naturally found sugars such as raffinose, lactose, fructose and sorbitol cause gas. Beans, broccoli, asparagus and whole grains contain raffinose, while lactose is the sugar found in milk and milk products. If you do not have normal levels of lactase, an enzyme that helps to digest lactose, you likely develop symptoms of gas and bloating after eating dairy products. Fructose is found naturally in pears and artichokes and is used in some soft drinks and fruit drinks. Sorbitol is commonly used as an artificial sweetener for sugar-free products.
Potatoes
Potatoes and other starches such as corn, pasta and wheat produce gas as they are broken down by bacteria in the large intestine. Foods rich in protein such as beef, chicken and pork rarely cause an increase in gas and bloating.
Fiber
Foods rich in fiber contain either soluble or insoluble fiber. Foods that contain soluble fiber, such as oat bran, peas and fruits are not broken down until they reach the large intestine, where they are broken down by bacteria and cause gas. Broccoli and cauliflower are other common culprits. Foods that contain insoluble fiber, such as wheat bran, pass through the intestines without significant digestion and therefore are not broken down by gas-producing bacteria.
Fatty Foods
While fatty foods are not a leading source of gas, they can engender the sensation of bloating. Consumption of fried foods can delay stomach emptying and slow the time it takes food to pass through the gastrointestinal tract. This leads to a sensation of fullness and bloating in the absence of gas.
