Your body is a communicative and guiding organ. If you talk to it, it will talk to you. If you listen to it, it will tell you what you need to know.
Your body will tell you when it is hungry. It will tell you when it is thirsty. It will tell you when it is full and satisfied. It will tell you it is overfull and uncomfortable. It will tell you when you have had a nice dose of dessert and it will tell you when you have overdone it.
Listen to your body and it will tell you what it needs and when it has its needs met. You do not have to only listen to your body when it tells you you have gone too far. You should be listening to your body long before that.