The reason is as follows: 1, soybeans have a substance called antitrypsin, if not too ripe, the presence of this substance can inhibit the absorption efficiency of protein, so in order to better achieve the role of soybean supplement protein, need to be fully cooked to destroy antitrypsin. 2, soybeans are not too ripe to eat after more likely to cause abdominal pain, bloating, flatulence will cause physical discomfort. 3, the soybean is not too cooked will exist pathogenic microorganisms, these pathogenic microorganisms if into the intestinal tract is also easy to lead to diarrhea, which will endanger the health.