True. I found that when I switched to a low-carb diet, my relationship with hunger changed.
For one thing, I was always hungry: nothing makes you feel full like a good batch of carbs. But the hunger was similar to a low-grade background noise; it was fundamentally different than the I-gotta-eat-right-now hunger of the carbolicious diet.
The other thing I noticed is that since I switched diets (7 years ago), I have never "bonked" (run into a wall because I was so hungry). I simply get more hungry, but again, it's more like the background noise gets louder.
That begs the question, "Why not eat more if you're hungry?" The truth is that eating gets tiresome after a while. I remember spending over and hour shoving salad into my mouth and finally saying, "I need to get stuff done; I can't sit here all day eating salad."
Yes, meat can fill me up if I eat enough of it (20 oz. prime rib), but I tire of meat after a while.
I can't comprehend what benefit it should have "to know real hunger" if you're a perfectly healty human specimen.
A lot of people are so habituated to large portions and frequent snacking that they're never meaningfully hungry, just somewhere on the spectrum between "reasonably sated" and "physically incapable of ingesting another morsel". Their eating habits have fundamentally broken the connection between food and sustenance. They've lost the ability to usefully distinguish between the body's natural hunger signals and other motivations for eating like habit, boredom and emotional self-soothing.
I'm not wholly persuaded by the claims made about the health benefits of intermittent fasting, but I do think it's a potentially useful psychological experience if you have a problematic relationship with food.