1. You eat too many FODMAPs - like sugars, alcohols, fructose that the body can't break down)
2. You're constipated - drink water, exercise, get sleep.
3. You have a gastrointestinal disorder
4. You swallow lots of extra air - carbonated beverages, chewing gum
5. Your gut needs boost.
6. You eat too many zero or low-calorie sweeteners.
Source: (What's Good)