Coarse grains refer to non-refined white rice and flour, usually referring to whole grains, miscellaneous legumes and tubers. Whole grains commonly include millet, corn, sorghum, oats, buckwheat, black rice, red rice, etc. Miscellaneous legumes mainly include red beans, green beans, kidney beans, black beans, fava beans, peas, etc. Tubers commonly include potatoes, taro, yams, sweet potatoes, etc. Coarse grains are rich in dietary fiber, which can help intestinal peristalsis and relieve the occurrence of constipation. Coarse grains are rich in vitamins and minerals and have a strong sense of satiety, so they are seen as a necessary food for weight loss and are often eaten to benefit people’s health. After eating coarse grains, the stomach digestion time will increase, which can prolong the absorption rate of glucose and improve the blood sugar fluctuation after meals to a certain extent, suitable for patients with diabetes, hypertension or cardiovascular diseases. However, coarse grains should not be consumed in large quantities because the accumulation of large amounts of fiber in the intestinal tract may cause indigestion and affect the absorption of nutrients, such as excessive consumption by adolescents may lead to the body not getting comprehensive nutrition, and affect development. In addition, the fiber in coarse grains may also interfere with the absorption of drugs and affect the effectiveness of drugs. Therefore, it is recommended that coarse grains and fine grains be consumed alternately or in combination, and the daily intake of coarse grains should account for 1/3 of the main food.