I think that this is an excellent question! I struggled with learning the difference between hunger and appetite. I had to learn to focus in on my body signals instead of what my brain and emotions were telling me. I am not sure how to describe the difference. I had to let my body get physically hungry a few times to learn. When I am hungry, my stomach feels empty and carrots will please me. If I only want carbs or junk, I am pretty sure that it is appetite, not hungry. Extreme hunger will make me get light headed but I don't let myself get there any more.
I think you should experiment. Plan your meals and a few times go 3 or 4 hours without eating to learn what physical hunger feels like.
Hope this helps.
Persistence is more important than Perfection
Continuous effort - not strength or intelligence - is the key to unlocking our potential. - Winston Churchill