" don't quite understand the fascination of the HN crowd with intermittent fasting."

I do hope that you will try it. It costs nothing, takes a negative amount of time since you gain at least a meal of free time out of it, and further, many people (like myself) find that it enhances athletic output.

I have never been on a "diet" in my life and have no affinity toward them (or that line of thinking at all).

You'll note that "diets" all focus on new and interesting things to eat ... fasting is the opposite of that (IMO, flawed) line of thinking.