Eating a moderate amount of coarse grains for a long period of time will not harm the body, but eating a large amount of coarse grains for a long period of time may hinder the absorption of nutrients causing malnutrition and gastrointestinal discomfort. Moderate consumption of coarse grains can provide the body with carbohydrates, fiber and other nutrients, which is conducive to the provision of heat, promote intestinal peristalsis. Coarse grains contain a lot of phytic acid and dietary fiber, phytic acid and dietary fiber will be combined with cholesterol, minerals, vitamins and other nutrients, so that their precipitation. Eating large quantities of coarse grains for a long time will affect the absorption of cholesterol, vitamins and minerals. Coarse grains are difficult to be digested, eating large quantities of coarse grains will affect the speed of gastric emptying, and the prolonged presence of food in the stomach will cause gastrointestinal discomfort, so people with gastrointestinal dysfunction can not eat large quantities of coarse grains. People should pay special attention to not simply long-term large amounts of coarse grains, can be combined with traditional rice and noodles to ensure adequate nutritional intake, to avoid damage to health.