Believe it or not, stress may cause bloating. When you are under stress, your digestive system fails to perform its function properly. Your bloating may be caused by constipation and stomach ache. So, try to free yourself from the negative emotions, and you will solve your problem for good.
Partially chewed food is slowly digested, and you get bloated. Simple as that. So, take small bites, and chew them well.
Excessive consumption of carbs may contribute to your bloated belly. Consider eating low-carb foods, and cut off your sugar intake and alcohol. Eat more fresh fruits and veggies.(Source)