Swallowing air while eating and drinking:

Eating quickly, talking while eating, gulping down hot drinks, or drinking carbonated drinks like soda can cause you to swallow more air without realizing it.

Some foods:
Legumes, peas, cauliflower, cabbage, onions, garlic, and dairy products can be difficult for some people to digest and cause more gas.

 

Indigestion:
When food is not digested properly, bacteria break it down, producing a lot of gas in the process.

Constipation:
When bowel movements are not done properly, air builds up in the intestines and causes bloating.

Lactose Intolerance:
This can cause gas and stomach pain in people who lack the enzyme to digest lactose, which is found in milk or dairy products.

Unhealthy habits: Lying down immediately after eating, lack of exercise, and overeating are also causes of gas.