When eating spinach and tofu, some people cook it in one pot and think it is the most ideal vegetarian food. But this is the wrong way. Because spinach contains chlorophyll, iron and so on, it also contains a lot of oxalic acid. Tofu mainly contains protein, fat and calcium. Boiling them in one pot will waste precious calcium. Because oxalic acid can react with calcium to form insoluble precipitate, it cannot be absorbed by human body. Therefore, in order to maintain nutrition, firstly, spinach and tofu are divided into meals, so that there will be no chemical reaction. Second, you can first blanch spinach in water, let some oxalic acid dissolve in water, take it out and cook it with tofu.