Why does hunger come and go in “waves”, even if you don’t eat anything?

Question

For example if you’re intermittent fasting or water fasting, and the hunger comes and goes in waves as opposed to just getting hungrier and hungrier by each passing hour. How come? I do intermittent fasting and my periods of hunger are brief. You’d think the longer I go without eating, the worse my hunger would get but instead, I just get these brief periods of hunger and they eventually disappear, as if I had already eaten.

In:

Answer 1

So does sleep, no? I get a wave everyday at 11 PM and then once I conquer that, I sleep at like 4, the next wave.