A fart is a mixture of gases in your large intestine. As bacteria accumulate around undigested food in your gut, they release gas, which builds in your intestine. Burping and belching are produced during the digestive process. As the stomach acids digest food, gas is created. When too much builds up, pressure builds, and gas seeks a means of escape. So farting happens. And it usually smells. Gag. Some foods produce more gas than others: wheat products, dairy products, cabbage, apples, radishes, broccoli, onions, cauliflower, and notoriously, beans. These are high-fiber, sugary foods that the body has trouble digesting. Womens gas smells worse because they produce more hydrogen sulphide, while men smell less but let off more frequently.