I find that my hunger level during fasting depends greatly on my level of hydration. And learning to like black coffee and plain tea helps a lot since they can feel more “substantial” than plain water.
I was watching a compilation clip about intermittent fasting [0] recently. According to Dr. Rhonda Patrick, coffee and other drinks than just plain water (and maybe vitamins and supplements as well?) break the fast by starting up some metabolic enzymes [1][2].
I guess there goes my round the clock tea gulping. :|
[0]: https://www.youtube.com/watch?v=JxjMdqevE88