Yes, the traditional saying that "green onion mixed with tofu is clear and white" has been completely subverted in these "food-eating" theories, and home-cooked green onion preserved eggs mixed with tofu is listed as one of the top diet killers. According to the book, tofu contains a lot of calcium, and shallots contain a certain amount of oxalic acid. If they are eaten, they will be combined into calcium oxalate, which is not easy for the human body to absorb and will lead to stones.