As someone who fasts for a full month of the year, I can chime in. It is true that you probably shouldn't do it for the weight loss alone, as you tend to compensate, or over-compensate, once fasting is broken.

That said there are many other benefits, as acknowledged by the author. Most people feel a heightened sense of awareness and clarity during fasting (the opposite of the lazy feeling after a meal). There is a reason most spiritual traditions include an element of fasting. Besides this there is a range of proven health benefits (Wikipedia cites reduced risk of cancer, cardiovascular diseases, diabetes, insulin resistance, immune disorders, slowing of the aging process, and the potential to increase maximum life span).

Just like exercising, it is 'unpleasant' for the mind to be forced into, but feels 'right' once you get it done and you actually grow fond of it in spite of the hardship.

I don't want to discount your experience, but as with a post advocating for fasting, you need to put a personal experience/your mileage may vary disclaimer on here, because your experience isn't going to be what everyone will experience.

I've done fasting in pretty varied ways. The longest was for eight days. What I usually do now is a 24-hour fast: dinner, skip the following breakfast and lunch, and then dinner.

When I fasted for eight days, I dropped about ten pounds. On a 24-hour cycle of fasting, I will drop between 1 and 2 pounds a day depending on activity level. I have never had the experience of gaining 20lb after fasting, nor have I ever felt like I was in famine mode. I think I gain weight a bit quicker than before I started doing the 24-hour fasts, but at the same time, it drops off quicker, too (it's true that fasting changes how your body stores and uses fat).

If you go from fasting back to junk food binges three or four times a day, yes, you will (unsurprisingly) gain the weight back. If you're putting 6k calories a day in, nothing about the effects of that are going to go away after your fast. If you go from fasting back to a reasonably balanced diet, the weight isn't coming back--if you aren't overeating, how could it?

This has been my experience. Your mileage may vary. I am not a doctor and this is not medical advice.

A long time ago I tried fasting for ten days on nothing more than water with a little lemon juice and cayenne (the plan was courtesy of a stupid book). After ten days, when I was ready to break my fast all nice and slow, I happened to pass by some fresh baked apple pie, which smelled like the best apple pie I'd ever smelled in my life. What do you think happened?

During my six-day fast, I dropped from 252lbs to 228lbs. After the fast, I leveled out at 233lbs and then continued to drop because I didn't return to my old eating and exercise habits.