Because beans contain a sugar called stachiose, and humans can't digest this substance normally. Because this sugar can't be digested well, when bacteria in the intestine try to decompose it, they will produce a lot of gas. Then people will fart.

Because all the food you eat will eventually become a feast for bacteria, nothing can stop the production of natural gas. Of course, the intake of pure liquid foods can reduce the generation of gases, because they usually leave no chance for bacteria to pick up leaks. A more feasible solution is to keep your mouth shut when dating and not to eat food that will produce bad smell.

Extended data

Normal people fart 5- 10 times a day, and the gas discharged is about 500 ml. When the fart is much more than usual, there may be stomach diseases such as indigestion, gastritis and peptic ulcer, as well as hepatobiliary and pancreatic diseases.

In addition, it may be because of eating, such as eating too many beans, potatoes and protein foods, or swallowing and inhaling too much air habitually. These are not symptoms and do not need treatment.

People's Daily Online-Revealing 10 Little Secret of Farting