How long has this been a symptom. Any changes in your diet? Are you lactose intolerant? Allergic to wheat? Any other allergies? Do you take pro-biotics?
Some people are lactose intolerant as mentioned by @dpworkin…so lactose free milk and lactose free dairy products may help. You would notice if you only get gassy a few hours after you have dairy products. Broccoli is a big culprit of gas, as are any kind of beans. Some people do not realize that if they have wheat products (breads, etc.) they can also become gassy. As @marinelife mentioned, you should keep track of when the gas occurs in relation to what you eat. You may test it out by eliminating one thing at a time and see if this works.
As already mentioned, dairy or wheat could be the culprit. Also, artificial sweeteners (aspartame and sucralose [Splenda] in particular) cause gas for a lot of people.
@borderline_blonde Wow, last night I ate pizza (wheat AND cheese) and have diet pepsi (aspartame).!
I think I may be lactose intolerant or something, because I always feel gross after diary products, and people have told me before it could be the reason.
Eating processed and uncooked foods can contribute to gas as well. Soda, chips, french fries, deep fried foods, alcohol, nuts and foods high in roughage can contribute to having extra fuel in the tank. Minimize your intake of these foods and try to prepare a many of your meals that you can instead of opting for fast food.