Before starting intermittent fasting I decided to try out a 24 hour fast, just to see how it would feel, and I felt abysmal and ravenous by the end. But after eventually starting intermittent fasting (which I ended up doing for at least 3-4 years), I had a few times where I would casually fast for nearly two days just by skipping my window one day, and it was not especially difficult.
Our bodies are so absurdly adaptive to just about anything we can throw at them. And so it makes sense, in some weird way, that if you're going to do something - doing it to an extreme degree can make things easier than going half way, since you optimize for the adaptive response from your body.
I've heard from many people who have had success with IF that somewhat more aggressive schedules (e.g. 20-4 compared to 16-8) can be easier to maintain.
I think it's just going to vary a lot by person. I tried a 12-8 fast which basically just meant skipping breakfast which seemed like a gentle intro. A few weeks in and I was so painfully hungry at times I was noticeably irritable and having trouble waking up. Also, didn't lose a single ounce.
I've not really tried fasting, at least not deliberately. I do notice that the times I get hungry differ depending on whether I'm at home or at work. Expectation of when you are going to eat does seem to factor into it somehow.
Our bodies are so absurdly adaptive to just about anything we can throw at them. And so it makes sense, in some weird way, that if you're going to do something - doing it to an extreme degree can make things easier than going half way, since you optimize for the adaptive response from your body.