Some people tend to add scallions when cooking tofu, but this is not scientific. Tofu contains calcium, while scallions contain oxalic acid. Oxalic acid easily combines with calcium to form calcium oxalate. This calcium oxalate is not easily absorbed by the human body, thereby destroying the nutritional value of tofu for the body. Therefore, it is not advisable to add scallions to tofu, so as not to destroy its nutritional components.