Sign 1: The baby\’s weight has grown to more than twice that of birth. Generally speaking, when a baby is about 3 kg at birth, he can start to add complementary foods when he grows to twice his birth weight, which is about 6 kg. Signal 2: The baby becomes hungry again within 4 hours after eating 250ml of milk. Before the baby is 3 months old, the stomach capacity is relatively small, so you will find…