First of all, pure coarse grains are coarse in texture and single in taste, so it is difficult to swallow. Therefore, few people can insist on eating only original coarse grains in their daily diet. Secondly, if people with delicate gastrointestinal function take coarse grains as their staple food every day, it is easy to cause abdominal distension, bloating and other discomfort symptoms, which is easy to cause indigestion.