Drinking carbonated beverages (soda, Perrier, beer) with meals contributes to gas and bloating. The carbon dioxide in these products increases parasympathetic function (a state of relaxation) in the digestive tract, which removes the contents of the stomach too quickly, before they have a chance to be properly digested. Consequently, the small intestine must break down the fats and protein, when it is actually designed to absorb the nutrients that have already bee broken down. This results in the production of gas.
In contrast, if you are an anxious person experiencing digestive complaints because your body is always in a sympathetic state (fight or flight), drinking carbonated beverages with meals will actually improve your digestion while you work on the cause of your anxiety!
