[grondilu]

This is only anecdotal but I had heard about the benefits of fasting for brain performance, so I once tried fasting during a chess tournament. I fasted during the first six days of the tournament. My results were disappointing so I gave up and broke the fast on the seventh day.

[stephc_int13]

I fast once or a twice a year for 3-6 days, and I practice "one meal a day" most of the year.

My first fast was difficult, I did not supplement with electrolytes, slept too much and basically spent the duration watching series and feeling awful.

It is much better to go outside, work and try to follow your regular habits.

Electrolytes supplements are a must, and also some paracetamol during the first few days to reduce the inconvenience of your brain switching from glucose to ketones.

Fasting is easier the more you do it, partly because of calibrated expectations and less fear but I also think that the body simply adapts.

The only difficult day is the first one, for me.

The mental clarity thing is not a boost, you won't gain IQ points or intellectual stamina, more like slightly enhanced mood and more stable/regulated mental performance.

[drivebyhooting]

Paracetamol is an anticholinergic isn’t it? It’s bad for your brain and its usage is associated with dementia.

[jprival]

> Paracetamol is an anticholinergic isn’t it?

No, per https://agsjournals.onlinelibrary.wiley.com/doi/10.1111/j.15...

Can’t say whether it’s good for your brain otherwise.

[toxik]

Are you really suggesting paracetamol causes dementia?

[jodleif]

Citation needed

[bobmcnamara]

"Regular use of paracetamol, but not ibuprofen, was associated with a significantly higher risk of new-onset dementia in the old population, regardless of genetic risks of dementia."

https://pubmed.ncbi.nlm.nih.gov/37633120/

[stephc_int13]

Paracetamol is the default painkiller for most people, I would suspect that regular use means some kind of inflammation.

I would not find surprising that chronic headache could be correlated with risk of dementia.

[boomlinde]

The study however found no such association between regular ibuprofen use and dementia. Not sure what compels people to go all "I have no idea what the supposed results of the study are but my amateur intuition about it tells me it's wrong".

[crackedbassoon]

That paper is extremely weak. Look at the confidence intervals surrounding the hazard ratios. There is almost no effect for paracetamol and the difference between paracetamol and ibuprofen is negligible. If this is the evidence, I’m not concerned.

[jodleif]

Thanks!

[EasyMark]

I tried this in the past, I absolutely could not last past 36 hours, all I could think about was food. The easier way for me was to do the Atkins fat fast, which basically 800 calories of 90% fat for a few days to kick myself into ketosis. I’m not sure why I needed with a capital “N” to have food when I tried a “hard” fast. It could be a mental block, as a child I was never allowed to skip a meal, even if I only ate a little bit. Weight didn’t become an issue until post 30 :)

[serverCurios]

I get very food focused in a fast as well. So I decided to "weaponize it" and use that focus to learn how to conjugate the Japanese verb Taberu (食べる), which means "To Eat." https://www.youtube.com/watch?v=s40x2zFJHI4

[dwaite]

I found a diet which is more carb-rich got my body used to wanting immediate energy from carbs. Capping carbs with a high (low PUFA) fat diet is a much easier ramp (for me) to keto, fasting, intermittent or omad.

[Attummm]

The reason why that happened is quite simple. You are currently accustomed to being in a fed state, and it will take a while to adapt to a fasted state.

Additionally, during the initial period, you may experience issues such as sugar withdrawal, which can lower your performance.

Your body’s cells will need to switch from predominantly using glucose to using ketones and fatty acids. This process can take weeks to months.

The body is able to use both glucose and ketones; this is called being metabolically flexible. This flexibility can be achieved through intermittent fasting.

So give it time.

[fbdab103]

Supposedly chess layers burn excessive calories playing. From one popular culture article[0]

  ...The six-game championship in 2004 left Rustam Kasimdzhanov 17 pounds lighter. And in 2018, one company tracking the heart rate of grandmaster Mikhail Antipov concluded that he had burned 560 calories in just two hours. Sitting still. Playing chess. (An average-sized person would need two hours on a treadmill to break 500.)
  Last week, ESPN looked more closely into the toll the stationary sport takes on the body. ESPN spoke with Robert Sapolsky, a Stanford University researcher who studies primates. Sapolsky explained that some chess players respond to the game like any elite athlete, burning upwards of 6,000 calories a day during tournaments, due to tripled breathing rates, elevated blood pressure, and muscle contractions. That means during tournaments they can lose two pounds each day.

I have done several fasts, and I am quite dubious of the supposed mental improvements. My brain has spent 99%+ of its existence no more than 12 hours away from a steady supply of glucose. I personally feel physically and mentally sluggish. While probably erring much on the side of caution, I avoid driving during a 5+ day fast because I feel my reaction speed is diminished.

Furthermore, the brain is the single most energetically expensive organ in the body. If there were a shortcut metabolic pathway, it seems like it would have been exploited long ago.

[0] https://www.menshealth.com/fitness/a29144951/chess-players-c...

[samatman]

Ketosis isn't a shortcut, it's a critical part of the human organism.

The brain has to run on something, and we store very little glycogen. It wasn't uncommon in the ancestral environment for food to be entirely unavailable, or for the only calories to be in the form of meat, which itself has little glycogen.

So there's a secondary pathway to account for those conditions. A hand-waving argument could be made that in circumstances where there are no calories, it is the most important time for the brain to function well. Glucose is the cheapest, metabolically, that doesn't automatically mean that it's the best.

The reaction someone has to a fast, or to a diet which induces ketosis, is fairly personal. I don't think there are broad sweeping conclusions we can draw here.

My n=1 is that after two days of a fast, I feel pretty sharp. Electrolytes are indeed essential to this; in this context salt is far and away the most important, for whatever reason. I would expect the YMMV factor to dominate though.

[QuantumGood]

I've played chess in the U.S. Open, NY Open, World Open in the 1980's (finished in the money in 2 out of 3). Really leaves you starving after playing for hours.

[Aurornis]

If you’ve been regularly eating meals multiple times per day, it will take your body much longer to start functioning well during a fast.

That said, I think the mental performance benefits of fasting have been excessively hyped. I wouldn’t expect a chess player who has been fasting for multiple days to have better mental clarity. The body goes into energy preservation mode when food becomes scarce for days. That includes reduced energy expenditure for the brain.

[wslh]

Just yesterday I mentioned here that I train for (olympic) triathlons [1], and in the context of that and this thread I need to eat much more because I lose significant weight AND, I feel much more nervous if I fast, and I am not a nervous person.

If I am not training I have the capacity to easily fast, not issue at all with fasting, not because I follow any intermittent fasting diet, just it is the way it is. Only sample=1 but I never observed any special enhanced cognition doing that while I observe an enhanced cognition function with very basic things like sleeping well.

One more thing, I also find an improvement in cognition more with running than with swimming or biking. There are many studies about that but I give my personal experience not trying to give any conclusion for everyone. YMMV.

[1] https://news.ycombinator.com/item?id=40533944

[mistrial9]

great going and good on you for your health BUT endurance athletics represents only an important but tiny fraction of the lives of adults. General conversation around health, fitness and tuning is easily derailed by outliers and insufficient context!! office workers with weak backs and wrists end up arguing with 20+ hour a week gym people over some aspect of diet, and then they talk past each other.. no problems with the comment but perspective and context are everything when talking health.

Most people in good health can practice some version of fasting with some common sense. Zero people with good health can train for "olympic triathalons" starting next week.. so a peek (peak?) at the life of a triathlete is interesting and perhaps commendable, but really needs calling out as an outlier in a general discussion.

[wslh]

I was clear in my comment and in a reference to a previous comment that people are different. I never recommended that you should follow my way of life but I shared some aspects of my healthy life because I considered that I am not doing any exceptional thing, healthy human-wisely.

> Zero people with good health can train for "olympic triathalons" starting next week..

Completely wrong. There are many paths to train for an olympic triathlon that doesn't start running, biking, and swimming and having the correct mindset, endurance, and physical state. It is like saying that a normal kid cannot learn certain things at elementary school. I am not a professional but an amateur.

[techcode]

As mentioned video I saw was newer than the news article. In the video I think doctor was talking about events like https://www.lowcarbusa.org/pioneering-ketogenic-management-f...

[techcode]

In another comment I mentioned UK doctors (so folks closer to couch potato than ultra long distance runners) basically saying let's do this.

Photo resembles guy I saw talking in a video about it (video was newer though) - otherwise it's first Google hit for "UK doctors diabetes keto running" and I'm yet to read through the article https://www.diabetes.co.uk/blog/2018/08/gp-type-1-diabetes-r...

[_yb2s]

There is a ton of research on this… high intensity exercise requires glycogen and cannot be done at the same level without a high carbohydrate intake. It is possible to walk almost indefinitely in ketosis, but it won’t really work for any kind of athletic competition.

[techcode]

Years ago I saw some YouTube videos featuring sports folks - from marathon runners, to someone row/paddling across the ocean - all of them being long term (basically permanent) on keto.

And also recently some UK doctors (some of them with diabetes - I mix the types so not sure which one) decided to prove a point by going low carb/keto, while doing long runs daily (about half marathon a day), to be sure they've definitely used up all the potentially stored glycogen.

[_yb2s]

It's pretty fascinating stuff, and totally doable. I stand corrected on the "any athletic event"- what I said doesn't apply to ultra long duration lower intensity events. Endurance will be higher but peak power outputs lower. For endurance focused events like the ones you described, I could see it being an advantage- everyone will run out of glycogen, but those already keto-adapted won't need to suddenly start trying to adapt during the event.

[Attummm]

Contrary to popular belief, fasting actually increases metabolism.

https://www.nature.com/articles/s41598-018-36674-9

[layla5alive]

Temporarily, and then it is dramatically reduced.

Jesus people, please stop with the unequivocal statements about equivocal/nuanced/complex things.

[shlant]

> Temporarily, and then it is dramatically reduced

No change of diet will "dramatically reduce" metabolism. This is entirely unsubstantiated

[_yb2s]

Not true, unlike many other mammals humans can survive a long time without food largely because the liver regulates metabolism in response to calorie intake. The thyroid hormone T3 is the main regulator aka “gas pedal” of cellular metabolism, and conversion of inactive T4 into T3 is done mostly by the liver. Conversion is halted when fasting or severely restricting calories… much to the frustration of dieters. This is why mainstream advice is to not lose weight too fast.

[layla5alive]

Indeed, and there are a few other mammals for which there are mechanisms to reduce ATP generation, reduce VO2, etc., and some which do it much better than humans do. Emperor Penguins, for example.

[Attummm]

Did you read the study? The study is about prolonged fasting, up to 58 hours.

They observed that metabolism Increased during fasting.

> During human fasting, metabolic markers, including butyrates, carnitines, and branched-chain amino acids, are upregulated for energy substitution through gluconeogenesis and use of stored lipids.

[_yb2s]

You are misunderstanding what that means… it is an up regulation of catabolism- breaking down other molecules and tissues for survival during fasting. Overall metabolic rate is drastically reduced during prolonged fasting, which is good, it preserves nutrients for survival.

58 hours is not a long fast in terms of total adaptability to fasting- humans can fast much longer, sometimes for months, and the biggest down regulation of metabolism usually happens later than this.

[Attummm]

Catabolism is an integral component of metabolism. Both anabolic (growth) and catabolic (breakdown) processes constitute the entirety of metabolic activities.

The study that I linked examines a fasting period of 58 hours. Fasting for 58 hours is considered a form of prolonged fasting. Prolonged fasting refers to an extended period without consuming food, typically lasting more than 24 hours.

[ralfd]

And did you play better?

Fasting is different than ketonic diet though. With fasting you also lose constantly salts/minerals/vitamins. Especially salt deficit will make on tired.

[EasyMark]

What do you think about drinking water with electrolytes or those electrolyte “salt”rich tablets that have magnesium, sodium, calcium, etc? (While fasting of course)

[Rury]

It's important while fasting. Your body needs electrolytes or you will have all sorts of health issues. Potassium is the most important one, followed by sodium. Every cell in your body has a sodium/potassium pump, which works to keep potassium inside your cells and sodium outside (creating a battery essentially). About 30% of all energy in your body is used just to maintain this pump.

Anyhow, potassium is the big one... many people don't get enough from their diet even while not fasting. And unfortunately supplements give very minuscule amounts of potassium (<=2% of RDI), supposedly because rapid absorption of large amounts of it can cause heart arrhythmias/attacks.

[Topfi]

Did you do a full "water fast" during those six days or an intermittent approach and did you supplement electrolytes or take any other supplements?

Genuinely interested, hope this doesn't read as the often common "you should have done this" reaction I commonly see when discussing certain diets or fasting.

[halfcat]

I recall someone, maybe Tim Ferriss, saying it typically takes him 6-8 weeks before he can do an equivalent workout on keto, and for high level endurance athletes much longer, like 12-18 months of adaptation before they start seeing clear benefits over their previous non-keto baseline.

So there’s an adaptation period, which is why it’s hard to do studies on this, because people starting keto cold turkey is likely to result in worse performance, mentally and physically, in the short term.

[iamacyborg]

High level endurance athletes are unlikely to be going full keto given the need for intra-race nutrition.

[coldtea]

I don't think it works that way. Probably should have eased in for months, doing fasting a day or couple of days per week, before tackling a 7 day fast head on, and at a demanding situation nonetheless!

[srik]

Did you take your electrolytes? If you don’t supplement on Magnesium/Potassium/Sodium you’ll have to deal with severely unpleasant effects on any water fast that spans beyond 2-3 days.

[grondilu]

No, I didn't take any electrolyte, as it seems artificial to me.

[srik]

Huge mistake. Water fasting is a breeze when done correctly and dangerous when not. The biggest risks are not supplementing the fundamental electrolytes because your body runs out of them in about 2-3 days and the second is not taking precautions to prevent refeeding syndrome. If you’d like to attempt another 3+ day fasting please read up on the fundamentals this time to ensure a pleasant experience. I love my headspace during an extended fasting, nothing quite like it. Two good sources to read up on this is the r/fasting subreddit’s wiki, (note the electrolyte and refeeding syndrome sections) and if you’d like something with more depth any/all of Dr. Jason Fung’s fasting books.

https://www.reddit.com/r/fasting/wiki/fasting_in_a_nutshell

[bzmrgonz]

I beg to differ sir.. (full disclosure.. I am no doctor, nor expert in the subject, I've just read a lot of material, and I have survived 8 years of water fasting sans electrolytes) I've been water fasting for 7 days every 3 months for the past 8 years. For maximum health benefit, it is my humble OPINIOIN that we should not consume electrolytes, not until the 10th day of water fasting that is. When I waterfast, I want my entire GI-track to be on vacation (park everything). Furthermore, I don't want my biological cells being "distracted" by any substance in the blood stream. I want them consuming fat(no conversion energy) and doing severe spring cleaning. I want tissue repair in the entire GI-track, I want tissue repair in the liver, kidneys, heart... everywhere. I want damaged white blood cells to be flushed out (due to calorie restriction)<to be replaced with new cells once I start eating> renewed, I want I want senescent cells<zombie cells) to be flushed out. I strongly believe that introducing salts into the body will prevent optimal health benefits otherwise achieved. I would however, consider the introduction of a substance to break-down plaque in the veins while I fast, something that would break down fibrin, which is the glue holding plaque together, but I have not found a good natural fibrin-disolving substance.