A hearty, warm breakfast, oatmeal offers up a bevy of benefits. It's a source of healthy carbohydrates, iron, phosphorus and potassium. A 1/2-cup serving of dry oatmeal contains around 4 grams of fiber, which is good for your health; however, in some cases, it might also cause gas.
Fiber and Gas
It's not oatmeal by itself that's likely to cause gas, but rather an abrupt intake of fiber throughout your diet overall. Ideally, you should get 20 to 30 grams of fiber a day, so cooking up a 1/2-cup serving of dry oatmeal can provide up to one-fifth of your daily fiber requirement. Fiber is a form of carbohydrate that your body doesn't digest, but bacteria in the large intestine break it down, leading to the creation of methane gas or hydrogen sulfide, which is the most common sulfur gas in flatus, according to the National Digestive Diseases Information Clearinghouse website. If you aren't used to consuming a lot of fiber, add it slowly into your diet to minimize the side effects of gas or bloating.