Many soda brands contain caffeine and that caffeine increases stomach acid levels. sodas also contain an array of chemical acids as additives, such as acetic, fumaric, gluconic and phosphoric acids, all of them synthetically produced. That is why certain sodas work so well when used to CLEAN CAR ENGINES! For human consumption, however, the effects are much less satisfying and quite precarious. Drinking sodas, especially on an empty stomach, can upset the fragile acid-alkaline balance of the stomach and other gastric lining, creating a continuous acid environment. This prolonged acid environment can lead to inflammation of the stomach and duodenal lining which becomes quite painful. Over the long term, it can lead to gastric lining erosion.

Another problem with sodas is that they act as dehydrating diuretics, much like tea, coffee and alcohol. All of these drinks can inhibit proper digestive function. It is much healthier to consume herbal teas, nutritional soups and broths, naturally lacto-fermented beverages and water to supply our daily fluid needs. These fluids support, not inhibit, digestion.
If you are still drinking soda, stopping the habit is an easy way to improve your health. Pure water is a much better choice. If you must drink a carbonated beverage, try sparkling mineral water.