Gas in the intestinal tract can come from two sources. The first is from gas produced by bacteria living in your stomach and intestines which digest food that you ingest, in the process producing gas as a byproduct. There are definitely certain types of food which tend to produce more gas when they are consumed (think about beans, for example), however each person is quite different, and foods which cause gas for you might be different than for others. The best strategy, therefore, is to keep a food diary to see if you can figure out which foods are causing the problem for you. If you can identify these foods, you can eliminate them from your diet which should take care of the problem. You should also avoid carbonated beverages, which are a universal culprit in terms of producing gas.
The other source of gas in the stomach is swallowed air. To reduce swallowing air, make sure that you eat very slowly, chewing each bite of food thoroughly. Also you may want to stop chewing gum, if you are a gum chewer, as that tends to be another way that people swallow a lot of air.
I recommend that you see your doctor
for an evaluation to rule out any potentially serious issues. Good luck!