Does the feeling of hunger go away by itself or you repress it somehow?
The first is what I think people in modern society call hunger, because it's the only kind they've experienced. It's a craving for food, or even just a sensation of not being full. We call "not full" "hungry" when they aren't really necessarily the same.
The second kind comes after you've fasted for quite a while. It's difficult to describe if you haven't felt it, but it's sort of like... tightness maybe as if your body is buzzing or something.
("Je hebt trek, honger hadden we tijdens de oorlog")
Appetite is a feeling I would describe more psychological. I'm smelling something delicious and suddenly want to eat it.
It is psycho-physiological addiction. (smell is not psychology, it is physiological). It is like cigarette addiction. But it isn't a physiological need.
Not having eaten for 2-3 days would be hunger.
I'm replying to your post because I get hungry even quicker. I had lunch (rump steak, potatoes) at 1pm and now at 4:30, I'm hungry again. My BMI Is 21, with rather low body fat.
Even with a BMI of 21, you can probably fast for 20-40 days with no irreversible damage, and that feeling you call "hunger" will not be there after the 2nd day.
You do not know what hunger is until you've felt it. I thought I knew what hunger was, until I fasted for 25 days. Then, I actually discovered what hunger is.
The first few days I get hunger pangs around my usual meal times, but they go away soon enough.
Around the fourth day I get the 'real hunger' feeling where it's your whole body aches for food, but the hunger pangs go away. But that had lessened by the end of my fast.
Even if you're not religious I think it's still worth giving fasting a shot, just because it teaches you about hunger. Most people in developed countries will never understand it.