The primary concern would be one of electrolytes: sodium, potassium and magnesium. Each person is different of course and he should consult his doctor before engaging into a water fast.
Moderate activity, running, body-weight exercises, etc. are ok. I once made the mistake of doing a heavy leg-weight workout (I was an internationally ranked alpine ski racer at the time) on day-3 of a fast. It went great but the bonk afterwards was waayy more interesting than i bargained for - treading the line of unconsciousness and had to break it e12hrs early.
Would definitely recommend zero instead of once, even if it seems to go well at the time.
I've fasted up to 5 days. It's an interesting experience but I wouldn't recommend it.
The only really interesting thing to say about it is that by day 3 I had entered the calmest period of my life. I'm prone to depression and anxiety, have meditated extensively, weaned off coffee...whatever you can think of apart from hard drugs I have done. Never felt so at peace looking at a wall for hours, total absence of intruding thoughts. Just immersed in a warm pool of grey space.
Only stopped at 5 days because it was affecting my sex life. I know people who have fasted for a month, no big deal once you get going.
I did it in my late teenage years, alongside many 24-48 hour religiously-motivated fasts. (In this case, they were water-only.)
24 hours isn't two bad. The second 24 hours is awful. That's when the headaches come. The third 24 hours your body starts stabilizing and it's pretty doable from there. Friends who went longer said it gets bad again in the second week.
I get tachycardia if I don't consume lots of salt throughout starting at 48 hours. I also have insomnia the first night regardless. It gets easier every time because you know what to expect and how to mitigate it.
There is no "conflicting alcohol evidence". Our body can handle at most 1 alcoholic unit per day (otherwise we would get alcohol poisoning from fruits fermenting during digestion).
Problem is: it's easier to not start drinking alltogether than being super careful about the quantities you ingest. Therefore the advice is indeed that it's simply bad and you should not have any.
Oh, absolutely. don’t start drinking for the health benefits!
I meant that there seems to be a never ending “one glass of wine is good for you” vs “all alcohol is bad”, with the former probably from alcohol lobby funded research, i guess.
Last week I did a 5 day Prolon fast. It is intended to provide the mentioned benefits, while still eating around 800 calories daily. For someone 6ft 3in / 240lb that seemed like it would make me hungry, but it was never a problem.
It is highly recommended.
In Graduate school I fasted for a week. It was deliberate as a cleansing activity for myself. Before this I had never really did any extensive fasting.
To directly answer your question, I didn’t talk to a doctor ahead of time, but I did make sure to drink lots of water during that period.
I remember the hardest day was day 2. For the first day, you “feel” hungry as your body is accustomed to eating, but it is day 2 you are genuinely hungry. However, per the article, after about the third day you simply don’t notice yourself being as hungry anymore.
I noticed then (and notice now when I fast) positive effects on mood, and ironically energy.
The only drawback I have noticed is that the first meal after a fast, especially if a large carbohydrate based one, seems to have outsized effects on drowsiness.
I've done multiple 3 day, multiple 5 day, and two 10 day fasts. The only intake in these was water and electrolyte stacks, and in one of the 10 days there was bone broth taken 2-3 times per day. All of these were self-induced without medical oversight, and the impetus was weight loss and testing myself.
To keep the take-aways short, here's what I found:
1. Do not attempt to do any sort of exercises that require real exertion (slow walking is fine) while doing fasting of any kind, and I would (given my experience with ketogenic diets) extend this to keto as well, especially when lifting weights. Despite what some liars and/or freaks will tell you, you cannot be fasted or ketogenic and maintain quality performance.
2. The 3 days are probably fine if you do them with a couple of months in between if you have other goals you're working on (like building muscle). Doing them every week will minimize any other fitness goals that you may have.
3. The 5 days and over left me feeling tired, but the tiredness would come in hard waves. For instance it was not uncommon to want to immediately fall asleep at random hours of the day only to feel wide awake at 2am the next day. Just being hungry messes with your sleep, and I suspect (but have not confirmed) that it probably messes with your circadian rhythm.
4. I lost more cumulative weight running two 3-day fasts than I did with one 10-day fast. This was confirmed against both of my 10-days. Most will attribute this to water weight, however in the +5-6 days after the fast ended I was still lighter with the cumulatives.
5. There were only a couple of times where I got that euphoric feeling that many claim to get, and that was only in the first two fasts I did. All subsequent fasts did not produce this.
6. In the last 5-day+ fast I did I experienced some weird neuropathy in both legs and hands, despite being fully hydrated and taking electrolytes. I immediately broke fast and felt better and have not experienced any neuropathy since.
7. I no longer do long term fasts, instead opting for intermittent fasting (16:8) daily for several reasons, coupled with not eating bread or pasta. This seems to have much better and more sustainable results.
Yeap, I would say the first 72 hours of any fast are the roughest for me. Electrolights and sparking water made the big difference for me. Green tea earlier in the day helped too as caffeine curbs some hunger.
Overall I’ve only been able to do longer fasts when OOO as my cognitive motivation is so low the first few days. Keeping just with tv shows / exercise / nerding out also makes a big difference when OOO and not noticing being hungry cause of work stress and reflexively wanting a snack as motivation to do more work.
Seems a bit pseudo-sciencey to me. "Brain cleaning" and "Immune refresh" in particular. Beware that even if correct, looking at this chart doesn't, in my opinion, really make you any better informed about the effects of fasting. Individual variability is high when it comes to eating. Also this doesn't seem to address the psychological effects of fasting - in my experience it induced an almost euphoric calm, which I later figured was probably the body releasing a bunch of hormones or something in response to a sustained unhealthy calorie deficit. In the end I realised that IF had become basically an eating disorder, and if you look at youtube videos of IF proponents you can find a lot of people with similar stories. Don't mix eating with philosophy, or only do so in moderation. You have very little chance of outperforming the evolved bodily systems for appetite etc with hard logic, numbers, and calculation. I've made similar mistakes with other kinds of diet, e.g. going round the supermarket craving a steak and thinking "hmm, maybe something mushroom-based". I don't do that anymore and I'm happier for it.
I think this is kind of a trap. It assumes that there is a default mode under which we're operating, and that something like IF is straying from a natural order.
But you're already obeying a philosophy of eating. The philosophy that you go out and buy things that will likely induce a lot of craving for more, the cultural norm that you will eat at times that are appropriate for the company you work at, etc.
Essentially you are eating by someone else's philosophy.
> which I later figured was probably the body releasing a bunch of hormones or something in response to a sustained unhealthy calorie deficit.
Yeah, not claiming that my hunches are any more scientifically valid, but that is my best guess from what I've read.
I agree and I do think it's good to take some degree of control over it, especially with the already unnatural environment we're subjected to. I just think there is another side to the IF story that isn't told as often.
I think people who are naturally good at sticking to things and are already interested in self optimisation etc are probably more prone to overdoing it and doing extreme diets like one meal a day or 30 bananas a day. The "intermittent" in IF is a bit misleading in my opinion, because none of the youtubers I was watching back in the day seemed to mention taking a break from it. It was basically choose an eating window like 6-10h and then stick to it rigidly, which to me doesn't really capture what I assume these people are going for - something more like the random periods of extended fasting that we might have undergone as hunter-gatherers.
I’ve done 7 days twice. The first started with food poisoning after a dodgy kebab and not being able to keep anything down. I had only water and sparkling water. The first thing you realise is that you don’t just eat because you’re hungry. I discovered that eating was triggered by a few other things like boredom. I found it hard to distinguish between genuine hunger and the burning sensation I get and in the end I convinced myself I wasn’t really hungry. Drinking water also satiates. Some other interesting things happens. I had 5 days without a poo. I could still run but only for 3k before bonking. I was naturally more tired but otherwise stuck to my normal routine. I had periods of feeling ecstatic which were amazing. Resuming eating was a bit of a let down too - I was looking forward to things tasting out of this world but I got none of that. You lose a ton of weight and your immune system gets a bit a refresh too.
This is just marketing for a company that sells “fasting mints” whatever the hell that means. There are plenty of reputable sources on the science of fasting and this isn’t one.
This writing is setting off alarm bells for me. It’s so confident in a field where it’s common to read researchers caveat the heck of everything.
I’m fairly certain there are accurate truths written on that page but I can’t help shake the feeling it’s being mixed with unfounded assertions.
>> Dr T. Dalton Combs PhD
I guess the title section made me think this was a medical doctor for some reason but the author never claims that so it’s entirely on me for thinking that.
>> Dalton earned his Ph.D. in NeuroEcomincs from the University of Southern California using neuroimaging to studying decision-making around food choices and in children with ADHD
I’m not sure what to make of this profile.
I’d need to do more research before I felt comfortable with anything written there but I can’t point to anything in particular setting off my BS alarm, I don’t know enough about the topic and the bits I do know look correct there.
I did 35 days on electrolytes/vitamins-only. The first two days were annoying, then it was a smooth sailing for a week (did two bike climbs at the end of the week) and then gradual decrease of physical energy/abilities while mental energy stayed constant. At around three weeks some feelings of euphoria arrived, then a week later the opposites. I was thinking whether to continue or not, but I reached my target weight (losing 1lb/day) and my weight loss slowed to less than 0.5lb/day so I called it quits. Refeeding was kicked off with a high-dose thiamine and some glucose to avoid refeeding syndrome, then I spent a week on bone broth, slowly adding more stuff in.
A few months later covid arrived, I got it and am not sure if the fast helped surviving it or actually worsened it as while I had almost asymptomatic run, in a few months it morphed into long covid. I think I depleted my B vitamins during the long fast and kicked off mitochondrial dysfunction as a consequence of covid.
I was looking for a discussion of vitamin metabolism under fasting conditions (which seems important in terms of one's health) - not a word, even though it seems to be studied quite a bit - and the body appears to halt elimination of watrer-soluble vitamins under fasting conditions, so it's worth thinking about.
Most people fast because they want to lose weight, I imagine. Here's a good discussion, including of uncertainties and unknowns:
"The circulating metabolome of human starvation" (2018)
> "Human starvation is marked by an early period of glycogenolysis and gluconeogenesis (3, 4). By 2–3 days into a fast, fatty acids released from lipid stores become the primary source of fuel; this critical transition to lipid metabolism allows for protein sparing during prolonged periods of starvation (3). What are the hormonal signals that mediate this transition from glucose to lipid metabolism?"
I'd guess vitamin supplementation under fasting is a good idea if the goal is to get your body to start consuming its stores of lipid fats.
38 comments
[ 2.5 ms ] story [ 87.3 ms ] threadWould definitely recommend zero instead of once, even if it seems to go well at the time.
The only really interesting thing to say about it is that by day 3 I had entered the calmest period of my life. I'm prone to depression and anxiety, have meditated extensively, weaned off coffee...whatever you can think of apart from hard drugs I have done. Never felt so at peace looking at a wall for hours, total absence of intruding thoughts. Just immersed in a warm pool of grey space.
Only stopped at 5 days because it was affecting my sex life. I know people who have fasted for a month, no big deal once you get going.
24 hours isn't two bad. The second 24 hours is awful. That's when the headaches come. The third 24 hours your body starts stabilizing and it's pretty doable from there. Friends who went longer said it gets bad again in the second week.
You wouldn’t take 10% the lethal dose of cyanide.
Clearly fasting for extended periods can be done safely, but it’s not unreasonable to ask the question.
Problem is: it's easier to not start drinking alltogether than being super careful about the quantities you ingest. Therefore the advice is indeed that it's simply bad and you should not have any.
I meant that there seems to be a never ending “one glass of wine is good for you” vs “all alcohol is bad”, with the former probably from alcohol lobby funded research, i guess.
To directly answer your question, I didn’t talk to a doctor ahead of time, but I did make sure to drink lots of water during that period.
I remember the hardest day was day 2. For the first day, you “feel” hungry as your body is accustomed to eating, but it is day 2 you are genuinely hungry. However, per the article, after about the third day you simply don’t notice yourself being as hungry anymore.
I noticed then (and notice now when I fast) positive effects on mood, and ironically energy.
The only drawback I have noticed is that the first meal after a fast, especially if a large carbohydrate based one, seems to have outsized effects on drowsiness.
This sort of makes sense from a hunter gatherer survival selection pressure too.
To keep the take-aways short, here's what I found:
1. Do not attempt to do any sort of exercises that require real exertion (slow walking is fine) while doing fasting of any kind, and I would (given my experience with ketogenic diets) extend this to keto as well, especially when lifting weights. Despite what some liars and/or freaks will tell you, you cannot be fasted or ketogenic and maintain quality performance.
2. The 3 days are probably fine if you do them with a couple of months in between if you have other goals you're working on (like building muscle). Doing them every week will minimize any other fitness goals that you may have.
3. The 5 days and over left me feeling tired, but the tiredness would come in hard waves. For instance it was not uncommon to want to immediately fall asleep at random hours of the day only to feel wide awake at 2am the next day. Just being hungry messes with your sleep, and I suspect (but have not confirmed) that it probably messes with your circadian rhythm.
4. I lost more cumulative weight running two 3-day fasts than I did with one 10-day fast. This was confirmed against both of my 10-days. Most will attribute this to water weight, however in the +5-6 days after the fast ended I was still lighter with the cumulatives.
5. There were only a couple of times where I got that euphoric feeling that many claim to get, and that was only in the first two fasts I did. All subsequent fasts did not produce this.
6. In the last 5-day+ fast I did I experienced some weird neuropathy in both legs and hands, despite being fully hydrated and taking electrolytes. I immediately broke fast and felt better and have not experienced any neuropathy since.
7. I no longer do long term fasts, instead opting for intermittent fasting (16:8) daily for several reasons, coupled with not eating bread or pasta. This seems to have much better and more sustainable results.
Overall I’ve only been able to do longer fasts when OOO as my cognitive motivation is so low the first few days. Keeping just with tv shows / exercise / nerding out also makes a big difference when OOO and not noticing being hungry cause of work stress and reflexively wanting a snack as motivation to do more work.
I think this is kind of a trap. It assumes that there is a default mode under which we're operating, and that something like IF is straying from a natural order.
But you're already obeying a philosophy of eating. The philosophy that you go out and buy things that will likely induce a lot of craving for more, the cultural norm that you will eat at times that are appropriate for the company you work at, etc.
Essentially you are eating by someone else's philosophy.
> which I later figured was probably the body releasing a bunch of hormones or something in response to a sustained unhealthy calorie deficit.
This sounds pseudo-sciency to me.
Yeah, not claiming that my hunches are any more scientifically valid, but that is my best guess from what I've read.
I agree and I do think it's good to take some degree of control over it, especially with the already unnatural environment we're subjected to. I just think there is another side to the IF story that isn't told as often.
I think people who are naturally good at sticking to things and are already interested in self optimisation etc are probably more prone to overdoing it and doing extreme diets like one meal a day or 30 bananas a day. The "intermittent" in IF is a bit misleading in my opinion, because none of the youtubers I was watching back in the day seemed to mention taking a break from it. It was basically choose an eating window like 6-10h and then stick to it rigidly, which to me doesn't really capture what I assume these people are going for - something more like the random periods of extended fasting that we might have undergone as hunter-gatherers.
I’m fairly certain there are accurate truths written on that page but I can’t help shake the feeling it’s being mixed with unfounded assertions.
>> Dr T. Dalton Combs PhD
I guess the title section made me think this was a medical doctor for some reason but the author never claims that so it’s entirely on me for thinking that.
>> Dalton earned his Ph.D. in NeuroEcomincs from the University of Southern California using neuroimaging to studying decision-making around food choices and in children with ADHD
I’m not sure what to make of this profile.
I’d need to do more research before I felt comfortable with anything written there but I can’t point to anything in particular setting off my BS alarm, I don’t know enough about the topic and the bits I do know look correct there.
We are doomed for good
A few months later covid arrived, I got it and am not sure if the fast helped surviving it or actually worsened it as while I had almost asymptomatic run, in a few months it morphed into long covid. I think I depleted my B vitamins during the long fast and kicked off mitochondrial dysfunction as a consequence of covid.
Most people fast because they want to lose weight, I imagine. Here's a good discussion, including of uncertainties and unknowns:
"The circulating metabolome of human starvation" (2018)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6141167/
> "Human starvation is marked by an early period of glycogenolysis and gluconeogenesis (3, 4). By 2–3 days into a fast, fatty acids released from lipid stores become the primary source of fuel; this critical transition to lipid metabolism allows for protein sparing during prolonged periods of starvation (3). What are the hormonal signals that mediate this transition from glucose to lipid metabolism?"
I'd guess vitamin supplementation under fasting is a good idea if the goal is to get your body to start consuming its stores of lipid fats.