Bloating, belching, gas and gas pains can be embarrassing and uncomfortable. Here's what causes these signs and symptoms and how you can prevent them. Bloating, burping and passing gas are natural and are usually caused by swallowed air or the breakdown of food through digestion. Excessive intestinal gas is most often due to inadequate protein digestion. Protein requires a lot of stomach acid to be broken down properly. Another main reason particular foods cause intestinal gas is your body’s inability to digest certain complex sugar compounds.