Gas is a normal byproduct of digestion. The intestinal tract typically contains up to three ounces of gas. Additional gas may accumulate as a result of eating patterns and dietary practices. Stomach gas is due to trapped air while intestinal gas will result from bacterial fermentation of food products in the colon. To avoid the discomfort and embarrassment caused by gas and flatulence, you need to pay as much attention to how you eat as what you eat.

Eating or drinking too quickly can cause you to gulp air in with your food, resulting in upper-GI gas. While everyone swallows small portions of air throughout the day, being nervous or hurried can cause some people to swallow larger portions. Chewing gum and sucking on hard candies also can increase the amount of air swallowed. Carbonated beverages, which by definition contain extra gas, can cause upper-GI gas. Experts recommend slowing down while you eat, taking smaller bites and avoiding chewing gum and hard candies.

Gas also can be caused by certain foods. Some foods, such as beans and broccoli, are notorious producers of flatulence. These foods have certain portions that cannot be digested, such as some complex carbohydrates and fibers, which enter the intestines but cannot be absorbed. Bacteria in the gut break down the unabsorbed food, giving off various gasses in the process. Foods that are known to cause gas include legumes and beans; cruciferous vegetables such as broccoli, cauliflower, Brussels sprouts and cabbage; dairy products (among people who are lactose intolerant); starches such as potatoes, wheat, oats, corn and noodles; fruits such as apples and pears; and sugar-free candies and gum containing sorbitol.

If you find yourself becoming gassy after eating these foods, you may want to eliminate some and cut down on others. Cruciferous vegetables are rich sources of vitamins and disease-preventing phytochemicals, so you may not want to eliminate them from your diet entirely. Experts recommend eating small amounts of the offending food often, slowing building your tolerance by eating it in increasing quantities. Your body will find a way to adjust to the food if you eat it often enough, and the gassiness should decrease. If dairy foods cause problems, you may be lactose intolerant. Many people in the U.S. have some degree of lactose intolerance; some can drink milk in small doses without experiencing discomfort, while others need to drink soy milk, another substitute, or lactose-free milk (such as Lactaid).