Tartary buckwheat rice is just an auxiliary food, just like corn kernels. When you add some corn kernels or tartary buckwheat rice to steamed rice, people will reach the standard of matching coarse and fine grains. Eating flour and rice is not good for human health. Rice contains a lot of electric powder and sugar. If you eat too much, you will get sick. Therefore, what people call "coarse grains" means eating more coarse grains and less flour and rice. That's the reason.