Here is the classic description from Ellen Satter:
What is Normal Eating?
Normal eating is going to the table hungry and eating until you are satisfied. It is being able to choose food you like and eat it and truly get enough of it--not just stop eating because you think you should. Normal eating is being able to give some thought to your food selection so you get nutritious food, but not being so wary and restrictive that you miss out on enjoyable food. Normal eating is giving yourself permission to eat sometimes because you are happy, sad or bored, or just because it feels good. Normal eating is mostly three meals a day, or four or five, or it can be choosing to munch along the way. It is leaving some cookies on the plate because you know you can have some again tomorrow, or it is eating more now because they taste so wonderful. Normal eating is overeating at times, feeling stuffed and uncomfortable. And it can be undereating at times and wishing you had more. Normal eating is trusting your body to make up for your mistakes in eating. Normal eating takes up some of your time and attention, but keeps its place as only one important area of your life.
In short, normal eating is flexible. It varies in response to your hunger, your schedule, your proximity to food and your feelings.
That definition is so good! It's nice to reread it occasionally.