How frequent to water-fast?

Dear fasters,
I just finished my first ever 5-days water fast. It was truly wonderful and eye opening and I can’t wait for the next time.
I wonder, is there a recommended frequency for water fasting? Does doing 5 days too frequent can be dangerous? And what is too frequent? I guess this may vary for every person, however, is there science-base guidelines?

Many thanks,


I try to do a long one every summer (prefer not to go too long during winter, since I can get quite cold after the first week).

My plan for the next few months is to do a 3-4 day fast every week. I did something similar three years ago and lost a lot of weight in less than 3 months. Unfortunately I gained some of it back during lockdown and everything else that happened last year. So I’m returning to what I know works.

I don’t see why frequent fasts of a few days should do any harm. Just as longas you actually have weight to loose an feel fine.


Science backs fasting quite heavily. Ill be reading alot in the coming weeks so as I find things relevant to you I’ll drop them here…

But mostly its depending on your goal. Some people fast five days a week, refeed for two days and repeat. Others feed for five, fast for two. Some alternate day fast. Or OMAD. Daily fasting windows such as 16:8. Some do longer fasts 10/21/30/40 days. It all very much depends what you aim is.

If it’s just health, disease prevention ect; quarterly maintainance 5-10 day fasts are quite adequate.
So is daily 16:8.

It only becomes unhealthy when it has the wrong motivation or impacts your metabolism due to not being in the right fuel state for your body. Such as kcal restricted dieting.
(Chronically under eating but keeping your body in glycogen fuelled state and never being in ketosis long enough for your body to do what it needs to do. )

Yasmin’s channel is really good (founder of this forum) and other good YouTube channels ive found are;

There’s loads of podcasts about on the subject now too.


I’ve found it’s a feel as you go along kind of thing.

I’ve done a month straight of 5 day fasts, and 4 day fasts.

If progress stalls, it may be time to change things up and keep the body guessing.

I just sketched out the next 6 months for myself, blocking out holidays. For the most part it looks like I’ll be fasting most weeks doing the 5 day and refeed on the weekends.

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If you still have your period, you should avoid block fasting on Days 21-28 not to tank your hormones. Listen to Dr.Mindy Pelz on YouTube- she has a whole series how women should fast different than man.
So I’m scheduling my fasts within 3 first weeks of my period and last week before the period trying to eat hormone-building foods. I did notice that just before the period I tend to get super hungry as well, so it’s easier to fast that way than to fight the nature :wink:
Good Luck!!

Interesting Diana, thankyou for this pointer. I follow her channel and have still missed this.

Personally I often fast even if I am due or not. For instance last year I hadn’t had a period for several years as I have the coil and once that settled in I just never had one. Then I fasted for 31 days and had three during that time and have had regular light periods for the next nine months. Towards the end of last year I stopped having them again and just had very occasional spotting. Yet as soon as I started fasting, in the first week I had a period. So as it stands I’m firmly of the opinion it’s still toxin release… And fasting as facilitated that period from me.

So I’m going to head to her channel now and see what she says.