First of all, pure coarse grains rough texture, and a single flavor, it is difficult to swallow, therefore, in the daily diet, very few people can insist on eating only the original flavor of coarse grains; secondly, the gastrointestinal function of the delicate people if every day to the coarse grains as the main food, easy to cause abdominal bloating, gastric bloating and other uncomfortable symptoms, prone to cause indigestion.