Advise on a 40 day water fast

I am 5 ft 8 in i want to water fast 40 days I am starting at 125 pounds. Will my weight be a problem? Also I ride horses and work at a horse farm 4 days a week. Can I do a water fast for 40 days with these conditions?

40 days may be a lot for your height/weight. Have you fasted before? Maybe do a 14 or 21 day and see how you feel? You could always keep going if everything is doing well.

That’s good to know going into it so that beyond 14 or 21 days I should not persevere if I have concerns. I’m just a little bit worried about perservering through discomfort if it’s life threatening and not just part of the detox cleansing process and not being able to decern the difference

I have never done a water fast before. But I have been researching them for years and I can’t get the idea out of my head and I really just want to do it

You can expect to lose a half a pound a day - taking you to 105 which for your height is probably not healthy. I’m 5’6 and would be anorexic looking at that weight.

Definitely check with your doctor.

Personally I’d fatten myself up first if I were in your shoes. Not hard for me to do😂.

Thats good information. It is useful to know the numbers.

Agree with Miramar, you will lose about 1/2 lb of fat per day for the first couple of weeks than it will drop to about 1/4 lb p/day (from what I have read). If you do not have body fat to spare, your body will start cannibalizing your muscles, so just be cognizant of how much body fat you have when doing the fast. In the very beginning you will drop probably 5-9 lbs of water weight almost immediately (the first few days).

What’s your reason for doing an extended fast? You could always start with shorter fasts (1-3 days) and work your way up.


My advice is this - Do it in stages, with a 4-5 day feed between.
The pro-fasting doctors seem to say as long as you have stored fat to burn, you should be OK as long as you are getting the electrolytes, vitamins, and minerals you need, but a longer fast can build up the uric acid, so keep up with some lemon juice and vinegar daily. Also, my blood pressure went all the way down to 100 over 65 around day 18, so watch for dizziness and eat (nutrient-rich keto) if you are not feeling well. You can always restart 1-2 days later. Your body is still in fat-burning mode, so it’s running efficiently and would recover quickly back to a fasting state from a low insulin response meal.
I had 60 lbs to lose, so I’m doing it in 3 stages. I completed my first water fast of 21 days, then ate for 5 days while staying in clean keto, and now halfway through my second 21-day fast. What I found during the last 4-5 days is that my metabolism seemed to be fighting back, so the weight loss slowed. Then I ate all I could in healthy keto (~2,500 calories/day) to keep my metabolism high and re-establish my “Set Point” at the lower weight, allowing me to start losing again on the 2nd fast.

In short, there is no benefit to a 40-day fast, when 2 x 21-day fasts would be safer and achieve the same or a better result.

I hope that helps.
Clint in Sac

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I am about about ready to start. I like your advice best of all from a theoretical point of view rather than the prior advice to start small with little fasts and work up to it because after all if i go through the the first few days it is going to get easier and I will start gaining more benifit from the consumption of less vital cells (the bad guys we want to get rid of). Thats what I have read at least. From the practical point of view I like the start small idea better but its not going to give me the fighting chance I need to repair damaged cells. 21/21 vs 40 is still going give me a fighting chance because that is still a lot of time for repair work. Is it true or untrue I have to refeed 21 days after fasting 21 before starting a second round of fasting?
I probably just need to start and see how far I can go keeping all of these numbers in mind and address it day by day based on my ability to do it and if I can keep going with it. And thank you for taking the time time to respond to me!

Autophagy begins almost right away on a fast, or after about 16 hours from your last meal. This is why even Intermittent Fasters get some cell and protein damage repair (autophagy) for a few hours every day. For us doing a longer fast, it is happening the whole time we are fasting, but there are diminishing returns, so there’s more autophagy going on Day 2 compared with Day 20.
I started my first fast with the idea of going for 60+ days or as long as it took to lose 60 lbs. The hunger was non-existent after Day 2, but by Day 21 I had the low blood pressure happening, plus there were so many great keto recipes I wanted to try, I stopped to eat for a few days. It did take me 4 days to feel ‘normal’ again, with the biggest issue being I found it hard to eat everything I had planned to. Since I stayed in ketosis for those 5 days, I found it super easy to start fasting again, and no hunger even on Days 1-2.
So, I’m simply saying “shoot for XX days”, but be flexible about the length of the fast (say, over 14 days), because you need to open to responding to what your body is telling you, such as a nutrient deficiency causing some issue or discomfort that a few meals would fix. Then consider something like a 2MAD IF for long term autophagy maintenance.
I am a Yasemin fan for motivation, but the best videos I have found on YouTube that address these technical physiological questions are from “Dr Eric Berg” and “Dr Sten Ekberg”. Search for those channels.
Hope that helps.
Clint in Sac

Haha. I always want more than I seem to have time for.

@Sheila_Coughlin your refeed should be half the time of the fast.

Dear Miramar.
Thank you for your input. I always thought it was the same length and then Clint just told me recently I can refeed for as little time as I want before starting again and your recommendations are half the time of the fast which is a good compromise between what I thought and what I just learned I will keep that in mind for my plan. Thanks again for your input. I am ready to begin. I have cleared my schedule for the next 21 days to allow for any rest I might need. My job is a combination of physical exertion and office work and I scheduled 90% of my work to be office work for the next 21 days.

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