3-day fasting is brutal. I don't think most people can do it.

I speak as someone who has fasted up to 1 week. Interestingly, the difficult period is exactly the initial 2...3 days. After that it's no effort at all - albeit physical performance seems to decrease, of course.

You may well be right about most people, but in my experience it's not that hard. My wife and I have been fasting for 3 consecutive days each week for over a year (we worked up to it over the previous year). It's become pretty easy now. I rarely feel hunger.

BTW, I feel I must add (for the benefit of random readers stumbling upon this thread) that most people should not attempt long-duration fasting. It may not be beneficial at all, and there are certain dangers associated with it. Up to 3 days is probably okay if you're overall healthy, but most people should stop around this point (I can't draw a firm line as it's not an exact science). 1 week becomes pretty sketchy for everyone.

The human body could go on like that for a few weeks actually, but I don't think there are any benefits beyond 2...3...4 days [research needed], and the dangers multiply rapidly the more you push into very long durations.

Drink water with electrolytes during fasting, e.g. a little bit of salt. If you drink just normal water, it's hypotonic and you'll lose electrolytes, bringing you to a hangover-like state - that might be brutal then.

Depends on what you do while fasting. I couldn't fast one day under heavy mental activity. I feel nauseous when I'm deeply thinking while coding for too long without eating.

@bitL is correct. 48-74 hour fasting has shown to regenerate new immune cells [1]

Also as others have said it, you go over a bump and it becomes easy. Also, there is a window where I'm rather productive and less ADD when I'm fasting.

[1] http://www.medicalnewstoday.com/articles/277860.php

> there is a window where I'm rather productive and less ADD when I'm fasting.

Something happens to the brain during prolonged fasting (within reason), and it's something that seems pretty darn good overall.

If you practice meditation, fasting seems to help a lot.

There are benefits to fasting for 10 hours: http://www.sciencealert.com/new-research-suggests-you-make-b...

The research was also summarized as "always gamble on an empty stomach."

And a better article about the study: https://news.usc.edu/63669/fasting-triggers-stem-cell-regene...

The published paper: http://www.cell.com/cell-stem-cell/abstract/S1934-5909(14)00...