1. Time and method of adding complementary foods to your baby. From birth, your baby only has breast milk or formula milk powder as its main food. However, as your baby grows and develops, you should start adding complementary foods around 6 months old. At this time, parents should choose simple and easy-to-digest foods, such as rice noodles, chicken puree, etc. In the process of adding complementary foods, attention should be paid to gradually increasing the type and quantity of complementary foods.