Reasons for baby\’s belly swelling After eating food, the body needs to digest it and break the food into smaller particles for the body to absorb. During this process, gas is produced in the stomach. However, the gastrointestinal system of babies is not yet fully developed and their digestive functions are not perfect, so the phenomenon of bloating is more common. In the intestines, intestinal bacteria can convert undigested food residues into organic acids, which will produce a large amount of gas and easily cause gas. In addition, some foods themselves are prone to producing gas, such as vegetables with high fiber content, beans, dairy products, etc. If the baby eats these gas-producing foods, it will also cause abdominal distention.