The baby who ate breast milk suddenly lost weight after six months because the nutritional value of breast milk could not be absorbed by the baby after six months. Be sure to add meals to your baby after the sixth month. You can give the baby some rice paste or egg custard. You can add some minced meat to the custard. Or add some millet and lean meat to the millet paste. You can cook porridge for your child, so that the child's nutrition will be particularly comprehensive.