Clinical did not find which coarse grains are not suitable for long-term eating, so do not believe the so-called which four kinds of coarse grains are not suitable for long-term eating. Coarse grains are relative to fine grains in terms of food, common types of coarse grains include cereals, miscellaneous legumes, tubers, etc. Cereals are commonly corn, millet, black rice, sorghum, etc., miscellaneous legumes are commonly soybeans, mung beans, red beans, etc., and tubers are commonly sweet potatoes, yams, potatoes and so on. The nutritional value of coarse grains is relatively rich, and appropriate daily intake can provide energy to the body. Coarse grains usually contain more fiber, B vitamins, etc. than refined rice and flour. The clinic has not found which common coarse grains are not suitable for long-term consumption, so you can eat coarse grains for a long time on a daily basis. However, it is necessary to match coarse grains with a variety of foods and not to eat only coarse grains for a long period of time to avoid unbalanced nutritional intake.