When chewing gum, the gastric acid secretes and they can kill the stomach ulcers. Long-term chewing gum causes problems like swelling and stomach inflammation. It is also worth noting that research has proven that those who chew a lot of foods tend to be more fond of consuming foods like fast food and sweets than vegetables and healthy foods. Advice: Chewing gums containing natural sweeteners (xylitol, sorbitol) are less harmful than those with sugar, cyclamate, or aspartame. Avoid chewing gum for more than 10 minutes, even on a full stomach.