Before babies begin to talk, they rely on you to understand their needs.  While this can be frustrating, especially during a crying episode. most parents can eventually interpret their baby's cues. As your little one's nutritional needs fluctuate, you will learn to recognize hunger and fullness cues. Hungry babies have a way of letting you know.  Gestures such as opening and closing the mouth, pointing to the mouth or at food, and appearing excited when formula is offered are all signs that your little one is ready to eat. Babies will also let you know they are full by closing their mouths, and refusing to accept food.  When full, you should stop the feeding.  Babies are still learning their body's hunger and satiety cues.  Forcing them to eat when not hungry can cause future appetite problems and obesity (source). Teaching your little one baby sign language can also help.  This is a type of communication your baby can use before knowing how to say words.  It prevents misunderstandings, and helps parents figure out exactly what their baby wants.