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Fasting & Programming (mahdiyusuf.com)
177 points by mccarthyjm on Aug 2, 2012 | hide | past | web | favorite | 174 comments

As (a non-religious) someone who tried fasting while holding down a similar job, my advice is simple: don't break your fast every night.

It only takes 24-48 hours for your body to adjust, your fat to start melting and your blood-sugar levels to stabilise. You also stop feeling hungry. I found that while I was generally a little 'light-headed' my powers of concentration were fine and I returned to full productivity.

At first I tried drinking only fruit juice but that gave me an upset stomach so I switched to water and the occasional tea. Once I'd got through the first day of 'starving' hunger I felt great: full of energy and positivity.

As long as you have fat on your body you should be fine, however I'm not sure it would be a good idea if you are all muscle: while shutting down your digestive system saves a load of energy, if you have no fat your body it will convert muscle.


  * No blood sugar swings
  * No hunger
  * Fat loss
  * A real sense of achievement

  * Greasy skin
  * Zits

  * Keep exercising to prevent muscle loss
  * Drink lots of liquid
  * Eat something light if the starving hunger returns
  * Be careful if you are already very skinny
  * Talk to a doctor

  * Binge eat every night as you'll feel starving again the next day
  * Ignore a return to hunger
  * Drink lots of fruit juice
  * Binge at the end. Gradually introduce food back to your system.

This was probably very common in the human experience prior to the development of agriculture. People didn't eat regular meals. Hunting opportunities would not have come along every day, and sometimes hunts would fail.

I don't think humans would become too weak to throw spears because they didn't have their Cheerios in the morning.

When I hear people who have skipped a meal complain "my blood sugar is low", I worry for their health. We have fat stores for a reason. Skipping a meal should not be a big deal.

Too weak to throw spears, maybe not. Too weak to churn out top quality code may be another matter, however.

You are severely underestimating the mental difficulty of spear hunting in relation to writing a couple of lines of code.

Mental activity requires a lot of glucose, whereas muscles can run on fat, protein or glucose. Additionally, people are adapted to minimise their mental output. So if you're low on blood glucose, producing a lot of mental output for >6 hours is a real stretch.

Really? I've spear hunted fish when I was a kid and shot targets with a bow (if I were a proto-human it could have been small animals instead) and both were pretty damn easy and not mentally taxing at all.

I love bow-fishing! But shooting targets as a child is hardly the same.

Getting a powerful, accurate shot in itself takes a lot of concentration. But when hunting for sustenance it means getting up before dawn, tracking animals for miles on rough terrain, and managing to approach the animal in complete silence. Once in sight you have to stalk the animal and look for the one perfect opportunity because if you miss or are too loud it will run and you will have to repeat the whole process again. Add in the stress that you and your small group have to be successful or your tribe might go hungry and it's a whole different ballgame then shipping code at the end of the day.

What was the risk of getting mauled while doing this?

The majority of edible animals are not big game (by nature of the food pyramid), and a even a decent chunk of big game are not predators of humans. Plus, it's easy to overwhelm them if you have more than one person.

I've never hunted before, but I can't imagine at all that it's a fair fight. Humans have been known to trap them, net them, flank them, shoot them at a distance, lure them, corner them, smoke them out etc. etc.

None of which requires a whiteboard, drafting paper or a calculator.

Are you really going to argue that any human with any semblance of intelligence (and I don't mean deep thought here) would have to risk mauling to hunt for subsistence?

Your post specifically said SPEAR hunting. You do not hunt small game with a spear. Trapping is usually the most effective way of getting meat in the wild.

Off topic but some of the best traps are large modern mouse-traps. Just make sure to drill a hole and tie it to a tree with a strong rope so the animal doesn't pull it away. Set it, and you will almost certainly capture a small mammal within a day.

He might have edited it, but I read "spear hunted fish", not "spear hunted". That does not look dangerous on TV.

Makes me wonder: when did trapping start? 5,000 years ago? 20,000?

Probably closer to 200,000+. Fishing net's are at least 80,000 years old.

> Are you really going to argue that any human with any semblance of intelligence (and I don't mean deep thought here) would have to risk mauling to hunt for subsistence?

That's why we invented farming, dear.

If you dropped me in a forest and required me to hunt animals with a spear, there would be significant higher-order mental involvement. For someone who has been doing it their whole life, I expect that is not the case in the typical hunt.

"When I hear people who have skipped a meal complain "my blood sugar is low", I worry for their health. We have fat stores for a reason. Skipping a meal should not be a big deal."

That is such a great point. People have been programmed around the 3 meal regime. I have found it fun to experiment with fewer meals and generally it works fine if I have an primarily protein breakfast I sail through to an early dinner.

It's gotten even worse now with many fitness gurus strongly advocating 6 small meals a day.

It's what works best for fat-loss, because that way you keep down the blood sugar spikes after every meal. I don't do it though because it's too much of a hassle - instead, you can also keep to foods which don't spike sugar levels much in general.

> It's what works best for fat-loss, because that way you keep down the blood sugar spikes after every meal.

That's a hypothesis that afaik no study was able to support (e.g. http://www.webmd.com/diet/features/truth-about-6-meals-day-w... about some studies. I don't have more references right now, but in the past I was looking for a study that supports it, and only found negatives)

> instead, you can also keep to foods which don't spike sugar levels much in general.

Google "bulletproof diet". I think you'll like it.

The other issue with people like me who chronically over eat, is that asking me to eat 6 small meals a day is like asking an alcoholic to go to a bar 6 times a day but only order pepsi.

I think a big part of the "low blood sugar" complaint is people misinterpreting their body. I used to get "low blood sugar" if I didn't eat for six hours or so, even getting headaches from it (I think 60% of the headaches I've gotten in my life have been from the placebo effect, and the rest stress-related).

People are just so unused to being hungry that they freak out when it happens.

You are mistaken if you think that hunting was the primary source of food in times before agriculture. For many tribes it was (and still is, in some parts of the world) a secondary "luxury" which augmented the gathered food. As you say, hunting can easily fail, or game can become rare because of environmental hiccups. This happens more often than you should think - there are times when deer can't be found for weeks. Blood sugar was mainly kept up with berries, roots, and fruit - nibbling all day long. Fat stores are not so easily accessed - if they were, then all-week-fasting would be the way to go for fat-loss (which mostly leads to muscle wasting and short-term water loss, and a mighty yo-yo effect). Yes, one can use intermittent fasting to lose weight, but weight-loss usually only kicks in after 2-3 weeks.

I agree that Cheerios are a bad idea generally, but I'm not pro fasting or skipping meals for weight loss. Fat is stored as an emergency reaction to high blood sugar levels, and you get exactly that when eating more between the fasts (you have to). You constantly expose your brain to too much and too low sugar levels, resulting in highs and lows in your ability to focus (and also your mood).

Yes, one can use intermittent fasting to lose weight, but weight-loss usually only kicks in after 2-3 weeks.

Citation needed. I personally know people who've lost weight long term with quite brief periods of intermittent fasting.

I think he's saying after 2-3 weeks of intermittent fasting, not fasting for 2-3 weeks at a time intermittently.

Anecdote alert, but I started doing alternate day fasting after I read the study, then 22 hour a day fasts after I read that people were having results with that. Went from 235 to 185 in 2 years (6' tall, fairly large build.) I'm not strict, and I go off it whenever I'm bored or severely tempted.

I count any drink other than water as a snack, and watch the bread, potatoes, and cornstuffs when I am eating. Who knew it could be this easy? I hadn't really been an overeater for years, I just had never had time to starve.

I think he's saying after 2-3 weeks of intermittent fasting, not fasting for 2-3 weeks at a time intermittently.

Yup, I got that and I'm challenging it.

Just making sure.

Thanks for the anecdote, by the way, very interesting.

I read that somewhere in this ebook on IF, don't recall on which page (great resource btw, one of the few user-friendly books I've seen yet): http://www.precisionnutrition.com/intermittent-fasting

I can't say anything about the people you mentioned. I myself had absolutely no progress when IFing for some days, only dizziness and irritability.

Are you sure about that? In the wild plant foods are only availiable in season.

Also, what about tribes that lived in places with cold winters? There are no plants to eat when the ground is covered with snow.

Times have changed. Nowadays we try to minimize our fat stores because overeating is a bigger threat to us than starvation is. If you're eating balanced meals intended to keep you slim, missing one is a bigger deal than if you pig out on a deer you killed and then miss breakfast the next day.

99% of the population has more fat store than in the days when people hunted deer.

The problem is that people aren't used to accessing their fat stores for energy.

> The problem is that people aren't used to accessing their fat stores for energy.

It is my hypothesis that most modern fat stores are not actually energy stores, but rather "toxin" jails (I use "toxin" in the sense of: a substance that the body does not want, possibly because it is harmful, and that takes non-trivial time/effort to metabolize and/or get rid of; think of e.g. mercury).

Which would explain why they aren't being used: In many cases, the body doesn't have a chance to get rid of them because bad stuff keeps coming in.

(You may laugh, but it is not inherently less plausible -- or less supported -- than the idea that fat stores are used exclusively as energy stores).

Doubtful; the primary way that mercury and lead are excreted is through your fingernails and hair.

But that happens at a very slow pace. Where do the mercury and lead spend time until they are excreted? The only answer I was able to get from people who are supposed to know is "all over", "in the cells", "in the blood" and similar meaningless answers.

I have yet to find anyone who has an idea about how it is actually distributed through the body.

> (You may laugh, but it is not inherently less plausible -- or less supported -- than the idea that fat stores are used exclusively as energy stores).

Burning fat for energy isn't an idea. As for your hypothesis, hypothesis doesn't mean making up random stuff.

Indeed, but please read what you quoted. I didn't state that "burning fat for energy is an idea". See the word "burning" in what you quoted? neither do I.

"fat store used exclusive as energy store" IS an idea or hypothesis. One that underlies a lot of other assumptions and theories about nutrition, but is actually known to be wrong -- fat is used for a lot of other things as well (your brain is mostly made of fatty acids, for one; the skin is constantly lubricated with fat for another).

My experience with this sort of thing is that despite thrice-weekly lifting sessions, I lose a LOT of muscle. Just a heads-up for anyone thinking of trying this.

> despite thrice-weekly lifting sessions, I lose a LOT of muscle

My experience is like the GPs (I only lose muscle if I don't exercise while fasting).

Do you have "nontrivial" muscles? My experience is that I don't lose muscles I use (If I don't jog, I _do_ lose leg muscles; if I'm not boxing or swimming, I _do_ lose arm muscles; but if I do both, and balanced exercises like crunches, squats, etc - I don't seem to lose anything).

This is also fascinating. I always assumed I was losing muscles, and perhaps I adjusted my exercise/fasting program to accomodate for this -- but I could have been deluded as I never focused on this point carefully.

You are probably not giving your body enough time to recover the muscles damaged in your workouts.

For more details i can recommend "Body by Science" by John Little and Doug McGuff.

Or google "muscle recovery time" and read through

Another con is 'seriously bad breath' (acetone breath) which is clearly not good if your job involves dealing with people face to face

> Another con is 'seriously bad breath'

Goes away after a few days. And probably good for you - it means your body is finally getting rid of some stuff it should have gotten rid of before and didn't.

> And probably good for you - it means your body is finally getting rid of some stuff it should have gotten rid of before and didn't.

That sounds like the sort of pseudo-scientific, unsubstantiated nonsense you hear all the time from New Age healer types. Do you have a source to back up your claim?

It's ketosis from ketones being produced as a byproduct of converting fat into glucose. Nothing to do with toxins.

Sounds reasonable. Can you explain why "acetone breath" only happens to some of the faster, and never (AFAIK) more than once per fast, or other than in the beginning? If it was as simple as you describe, it should be very consistent or completely random.

p.s: I don't see anyone mentioning toxins before you did

I think it depends on how much glucose and carbohydrates you're getting in your diet. Your body needs a minimum level to survive (eg. for brain function) and if it doesn't get it, it converts fat. So if you're on a low carb diet, but getting at least that bare minimum, you won't get ketosis. Something like that, anyway.

You were the one who started it:

> your body is finally getting rid of some stuff it should have gotten rid of

Sounds like woo-woo toxin theory to me. There are fat-soluble toxins, but I doubt they'd be enough to make you sick or smell bad.

> I think it depends on how much glucose and carbohydrates you're getting in your diet.

Let me rephrase the question, as apparently it wasn't clear:

Most instances of fasting (specific time + specific instance) do not get acetone breath at all.

Some instances of fasting do get acetone breath, but if they do, it's usually only for a couple of days near the beginning of the fast (usually starting around 2nd day and ending before the 4th day), even if the fast goes on for 3 weeks.

Your explanation does not seem to make this dichotomy possible - it seems to imply an all-or-nothing situation (for a specific instance). Can you extend your description to accommodate this observation? [Note: based on personally collected set of anecdotes - I couldn't find any rigorous collection of this data]

> Sounds like woo-woo toxin theory to me.

I specifically avoided "toxins" in this reply (but not in others) because toxin theory is not well defined, and can thus easily be ridiculed to death. If you define it more properly, (e.g. caffeine "detox"), it is exactly as described, it does make you feel sick. Technically, caffeine is poisonous (as is alcohol) - it's just that in small doses, we as a specie seem to like the effect it produces.

I'm not sure what you mean by an "instance", but there will likely be variations in how quickly people respond to metabolism, and also depends on what you're eating during the fast.

One possible mechanism is that the muscles of the people fasting are more able (either through genes or exercise) to burning fat, meaning that you need to convert less fat into glucose. I'm not a biochemist (I've mainly read Good calories, bad calories plus various primal/low carb blogs) but it seems pretty straightforward (fat -> fatty acids -> acetyl-CoA -> ketones): http://en.wikipedia.org/wiki/Ketosis

Feeling sick on a caffeine detox is likely to just be withdrawal, and/or the "low-carb flu".

> I'm not sure what you mean by an "instance"

I defined it earlier: specific person, at a specific fasting period (by which I meant contiguous period).

> also depends on what you're eating during the fast.

I don't think we're talking about the same thing. "fast" says "what you're eating" is nothing.

Eating nothing for three weeks?! That's stupid and dangerous.

You're putting your life at risk from heart attack and kidney and liver failure (and other people's, judging from your comments in this thread).

> Eating nothing for three weeks?! That's stupid and dangerous.

To quote other people on this thread - "citation needed". I've done this more than once, actually, and I know others who do too.

Yes, I have eaten essentially nothing for three weeks. No, I wasn't putting my life at risk of anything, though you may believe what you want -- did you notice that I'm not the only one who posted about long fasts? You just assumed everyone was eating, but we use "fast" literally, not as a codeword for "calorie restriction".

Although I had the references to support that it's healthy, I did do bloodwork a couple of times through, and at the end, it was -- in fact -- much, much improved. For example, my B12 levels went from -2 sigma to +2 sigma. (If this sounds impossible to you, read the wikipedia entry about B12 - the general "knowledge", even among doctors, about B12 is unbelievably incorrect).

My doctor, who is a reasonably open minded MD, looked at the results and said "just make sure you start eating when you are feeling hungry". That happened 21 days after I started. He wasn't worried after looking at my bloodwork.

If you're healthy at the beginning, irreversible damage starts around day 40 (but is very swift at that point). There are quite a few people in India who do 30 days every year for religious reasons, and suffer no ill effects -- and have been doing this for centuries.

Given what you've said here, I highly suspect you do long-term fasting within some sort of "yogic" context. I personally suspect that many of the potentially negative outcomes of dietary depravation are mitigated when in a positive environment (i.e. lots of nature / with good energies) complemented with certain types of yogic practices. There is also a long tradition of long "fasts" within Chinese qigong traditions, and the supposition is usually that a body attuned via various practices can feed off of the environmental energies (e.g. the sun, the mountain) without needing nutrients of other sorts. The technical aspect of some of these things is a bit beyond me, both because it is 'esoteric' and doesn't fit into any model of Western science that I know of (with the potential exception of Paracelsusians).

Along these lines, I'm curious what sort of environment you or the other people you know do their long fasts in (i.e. if there is a checklist of sorts).

> Given what you've said here, I highly suspect you do long-term fasting within some sort of "yogic" context.

Actually, no. I'm hopelessly unreligious and unspiritual (or whatever the right adjective for "yogic" is).

> Along these lines, I'm curious what sort of environment you or the other people you know do their long fasts in (i.e. if there is a checklist of sorts).

I know some people who practice it in nature or a retreat of some sort, usually in some "yogic" or equivalent context (i.e. with others doing the same, and usually with a guide)

However, myself (and a couple of friends who followed after witnessing the effects on me) were doing it in the everyday environment, with no special support or anything.

In fact, that first 21-day fast happened accidentally - it was finals time at the university, which meant I spent all of my time studying and exercising (I discovered exercise makes studying much more effective). And then I was feeling really sick for two days (nauseated, congested, tired), and lost my appetite. And then I was well again, but my appetite didn't come back - so I didn't eat. (And those two days were the only days of that month that I didn't spend ~2 hours doing physical exercise)

After 4 days, I was starting to get curious - I was feeling better and better all the time, mildly euphoric even, and yet disgusted at the thought of food. Long story short, within a couple of days I found quite a few trustworthy references that were compatible with what I was going through, and that mentioned that even if I don't feel appetite coming back by day 30, I should eat.

A called my (conventionally trained, though unusually open minded) MD just to be sure, and he said "let's do some bloodwork to negate illnesses (a) (b) and (c) which cause loss of appetite and need treatment, but otherwise - just keep listening to your body". Which is also why I know that my B12 improved significantly through the fast. And indeed, I did feel hunger after 21 days. (And hunger is actually a different beast than appetite - a beast I think almost no one in the western world knows - it is a feeling of "i must eat now" that does not go away when you're doing something interesting, which is very different from regular appetite in ways I can't really put into words)

Later fasts felt good, but not as good -- possibly because my starting condition was better.

Fascinating. What were the "few trustworthy references" you found? I've never heard anything like your experience before, and the anecdotal evidence I've heard regarding fasting is largely gathered from spiritual traditions (i.e. Yoga, Christian, etc.).

1. My grandmother was a doctor who had treated a lot of holocaust survivors, and collected their stories, which she later told my entire family. Several were about "miraculous improvement" in health conditions; some of it was, of course, survivorship bias (no pun intended ...) - those who were killed first where the less healthy and less able. But my grandmother had medical reasons to believe that a big part of it was nutrition (or rather, lack of it for long stretches at a time) -- especially because after the war, with the availability of a variety of foods, many illnesses came back. On that week, I verified with the family that I remembered her stories and conclusions correctly.

2. I found a book by Bernarr McFadden http://en.wikipedia.org/wiki/Bernarr_Macfadden (can't remember the name right now) that correctly described my experience (it's hard to find descriptions at all; and everyone around has the anthonyb opinion that I'm about to die because I haven't eaten in x days). That book had very old references (from the '30s) about fasting practices in some indian castes - which I was then able to altavista (that was before Google hit the scene) and confirm

3. I consulted my doctor, and a friend who had finished his medical studies and was doing his internship at the time. Both had the immediate anthonyb reaction, but a few minutes later conceded that any of the things they feared would trigger horrible pains, blackouts, etc - and that couldn't be right as I was feeling good.

YMMV. 1) and 3) may not be available to you. 2) was available to me from the university library, but I'm not sure where I can find it today. But it was available to me at the time.

Your b12 will be up because your body is cannibalising its tissues to stay alive. That's your liver, kidneys, etc. and it doesn't mean that you're healthier.

Given that you don't know that, and earlier on you didn't know what ketosis is, I'll take your dietary advice with a large grain of salt...

Wow. I mean, you have all the answers!

I did know what ketosis is. But ketosis DOES NOT induce acetone breath in 99.9% of the population*time - which is what I understood you asserted. Look it up. Really, look it up.

And you better read about b12. You are radically misinformed. Not that I care - it's your health that will suffer. Really. Look it up.

No, you go look it up: http://en.wikipedia.org/wiki/Vitamin_B12#Foods.

What's the top source of B12 on that list? Now, given that you're not eating beef liver, which liver do you think is providing all that B12?

Stupid. Dangerous.

Edit: Thinking about it, I'd put fasting for 3 weeks in the same class as running a marathon: if you can do it, you're probably healthy. Actually doing it though, is not healthy at all.

No, you read the article you quoted: Under "Foods", the section you linked:

... Ultimately, animals must obtain vitamin B12 directly or indirectly from bacteria, and these bacteria may inhabit a section of the gut which is distal to the section where B12 is absorbed.

Under "synthesis and industrial production":

.... Neither plants nor animals are independently capable of constructing vitamin B12.[30] Only bacteria and archaea[31] have the enzymes required for its synthesis.

And a little later:

.... The total world production of vitamin B12, by four companies (the French Sanofi-Aventis and three Chinese companies) is said to have been 35 tonnes in 2008.[40] Most of this production is used as an additive to animal feed.[41][citation needed]

It doesn't matter what the top source on the list is if you can have it synthesized in your own body. Which I now do way better than I could before my first fast. You know why cow liver has B12? Because cows are fed B12 these days so that beef liver would have enough B12 for human consumption! That's so ridiculous and inefficient it is sad.

You know why B12 synthesis is so horrible among both humans and livestock today? Because of how much we use antibiotics. And there's also another surprising finding: The human body (and most other mammals as well) have a cache of the organisms required to synthesize B12 and a host of other useful stuff. It's called "The appendix", you might have heard about it. The body will release these organisms from its cache under ketosis lasting more than a few days, to replenish and revive the useful colonies. Nature is very smart like that -- a few days of fasting are completely normal when your food source dries up. So the body uses that period to do maintenance. [I'm not going to spend time looking for the refs right now, partly because I no longer have access to full article texts, and mostly because I don't have the time; But this was hypothesized decades ago, and AFAIK conclusively proved something like 5 years ago, although it's not really well known so far even among professionals who should know better]

> Stupid. Dangerous.

Religious, is all I can say about your responses. You know things to be right, like it is dangerous to fast, or (I assume, although you might already be enlightened about these subjects) that dietary cholesterol is bad for you (it's almost independent of blood cholesterol, which is an important marker, though not a cause for disease), that you shouldn't eat more than a few eggs a week (nonsense; eat as many as you want - 20 a day is not unhealthy), that low-fat dietary intake is good for you (it's not), that butter is bad for you (it's excellent for you if it's from healthy grass-fed cows), that weight change is exclusively a result of caloric balance (only in the useless tautological sense), that you should minimize salt intake (too little is as bad as or worse than too much), or that cushioning is good for your feet and that's why sports shoes have them (they're bad for you except for very specific circumstances; they were championed by marketers, not researchers).

I try to challenge my beliefs and understand why I have them. I often (way too often, unfortunately) find that things everyone (including myself) takes for granted are actually better classified as "wrong leaps of faith" or even downright superstitions than science.

When someone contradicts me (and it's something I haven't researched and do not have a good basis for my beliefs), I try to start again from a blank slate, rather than find support for what I believe in (because you always can do that, regardless of how wrong you are).

> Edit: Thinking about it, I'd put fasting for 3 weeks in the same class as running a marathon: if you can do it, you're probably healthy. Actually doing it though, is not healthy at all.

I don't think this analogy is proper.

Evolution surely did prepare you to run short distances. Evolution did not prepare you to run a marathon - you have to practice to be able to do that, regardless of how healthy you are - and I agree it is probably not healthy (although I have no support for that - for all I know, done properly, it might be super healthy).

Evolution did prepare you to survive if your food source dries up (at least for a short while), or if you sprained your ankle and can't chase your prey or climb the tree to get food. In fact, it's apparently piggybacked some maintenance jobs on this period because (at least pre- agriculture) they were guaranteed to happen relatively often.

You may argue about how long that "short period" is - evidence collected mostly from religious fasting is that it is around 40 days when you are healthy.

> if you can do it, you're probably healthy.

I disagree in general, but there's an important point here that I must stress - it would probably have been unhealthy for me, had my appendix been removed (which is not uncommon), given the explanation above. However, the reason I started fasting was not religious or weight motivated - I simply had no appetite. So I didn't eat. The appetite came back 21 days later. I have since fasted several times in periods of 7-21 days, once every couple of years, sometimes prompted by loss of appetite, and sometimes by wanting to experience the health benefits.

I would not be surprised if appendix removal would have triggered appetite much earlier. And I would also not be surprised if evolution did not prepare humans for a removed appendix, and I would have suffered some irreversible damage as a result. I really don't know about that. (If you feel vindicated about this being "stupid and dangerous" - we have a difference of philosophy here, that I'm not going to argue about)

* edit: Forgot to mention - I've been vegetarian for the most recent 90% of my life, and vegan for a nontrivial part of that - during which I never had a good source of B12. If B12 could only be sourced from food intake, I'd be dead before the age of 12 (which is why I already knew 15 years ago that the prevailing B12 theories were bullshit, despite not having a better explanation at the time). But I was only dangerously low for a 6-month period in my twenties - other than that, I was just "low, but not dangerously so" until that fast.

No, I do not have a source to substantiate it; I'm not sure what the study would be to look for. It is based, however, on personal experience and experience of other people I know (disappearing of bad breath coincides with other very positive and welcome changes, like injuries that were healing very slowly starting to heal at an amazing pace, disappearance of snoring, and similar things).

Just a question - would you have reacted the same if I wrote "it isn't bad for you to eat 20 eggs a day", or "eating cholesterol isn't bad for you"? because both of these "accepted wisdoms" (limit egg consumption; dietary cholesterol is bad for you) are unsubstantiated nonsense you hear from everyone (laymen, nutritions, doctors), with no study to support them. And yet they are almost never challenged.

> Just a question - would you have reacted the same if I wrote "it isn't bad for you to eat 20 eggs a day", or "eating cholesterol isn't bad for you"? because both of these "accepted wisdoms" (limit egg consumption; dietary cholesterol is bad for you) are unsubstantiated nonsense you hear from everyone (laymen, nutritions, doctors), with no study to support them. And yet they are almost never challenged.

I would have either asked you for citation, or did my own research. But even if I haven't, two wrongs don't a right make. People are biased, and selectively accept garbage. Unsubstantiated nonsense is garbage, irrespective of its acceptance by people who know nothing about it and are accepting things on what makes them feel good.

> Unsubstantiated nonsense is garbage, irrespective of its acceptance by people who know nothing about it and are accepting things on what makes them feel good.

That's true, and describes 99% of what people believe. It's just that I never see any of the mainstream proved-wrong beliefs challenged on HN - they either get a response like "no, that's wrong, and here is a reference", or accepted as gospel. Not surprising, really.

No one is saying two wrongs make one right. I clearly stated that I don't have a reference anyone can check.

I don't get hunger when I don't eat. After almost a day without eating I get headache then I feel weaker and weaker and don't even have enough energy to make myself something to eat. Then I fall asleep. Only after I wake up next day I have enough energy to make myself a meal. I'm still not hungry but reason just has the opportunity to kick in.

I am currently working in Saudi Arabia (here, fasting is a national rule, however I eat because I'm a Indian and non-Muslim) as a programmer, and I've noticed one funny thing - people just become nocturnal. They eat and work in the night and sleep during the day. This is simply the normal routine reversed. Fasting has minimal effects on them, its not fasting, just the time in which they eat is changed! They work shorter during the day and do the hard work in the night.

Humans are funny creatures. To believe on the one hand a god laid down these rules, and then in the same thought think "Well I bet he didn't think of this loophole"

I remember having this same thought when I learned about the existence of "Islamic finance." Apparently, Islam has a strong doctrinal prohibition against charging interest, and there's an entire thriving sector of Islamic law and business dedicated to structuring transactions in ways that don't technically charge interest but still yield a return on principal. http://en.wikipedia.org/wiki/Islamic_banking

This reminds me of a little kid beating up his classmates on the playground being told by the playground monitor to stop touching them, and then turning around going back to tormenting them by starting to punch them and stopping just short of making actual contact, and saying "neener neener, I'm not actually touching you." Except here, instead of a playground monitor, it's...an omnipotent creator deity.

My understanding is that a generous portion of Rabbinic legal theory is about tapdancing around the Mosaic law.

Because most observant jews would not, I can only assume, want their children to be stoned to death for giving them a bit of cheek. Or have to be beaten up because they shaved. And so on.

What strikes me odd about biblical law is how little of it is devoted to elucidating the big questions. Such as: what about the corner cases to the Ten Commandments? Is killing in a war forbidden? What about self-defence? And so on.

Islamic finance is a fairly complicated subject. As someone who has no background in finance, I have been trying to understand some basics.

But overall, what I understand is that for a bank to give out loans, they must also provide every opportunity to help those who are borrowing money. For example, they can extend the payment, provide advice etc

The main thing about Islamic finance is that it is all asset based. You can take a loan to buy a car, but you can't take a loan to renovate a house etc. This is to stop people from borrowing when they can't possibly pay back. There are few models for unsecured loans. But, as I said, its very complicated.

Isn't there whole sections of Judaism that work out loopholes to God's laws?

One of my favorite Talmud stories illustrates that the opinion of the community is more important than the voice of God - which, in my opinion, is one of the many things that make my religion great.

Going to badly paraphrase here, but a group of Jews were debating an obscure point of law, and a single person was in the minority. He said something like 'if I am correct, let this tree demonstrate it!' The tree was suddenly torn from its roots and flung far away. The rest of the people scoffed - 'a flung tree doesn't prove anything.' The solo dissenter cried out 'if I am correct, let this stream prove it!' And all of a sudden, the stream began running backwards. Everyone else said 'what does how water flows have to do with this issue?' Finally, the one guy said 'If I'm right, let the voice of God cry out!' And they all heard the voice of God, saying 'why do you keep disagreeing with this man, when all the forces of Heaven keep demonstrating his correctness?'

A rabbi spoke up - 'it's nice that you say so, but it's not for Heaven to decide - the Torah is not in Heaven, it's down here with us. You gave us the Torah at Mount Sinai, and from now on, it's up to us to interpret it.'

God was delighted, and burst out laughing, saying 'My children have defeated me, my children have defeated me!'

So yes, you might think of them as loopholes, but we prefer to think of them as the legitimate interpretations of the community. A good thing, too - have you ever read the Torah (aka the Old Testament)? Without the wisdom of the community, the religion would be unworkable - many of the laws within aren't remotely relevant for modern life.

Yes. One instance is the law that says that a child should be executed if he disrespects his parents (one of the ten commandments).

The text says the parents must "speak with one voice" of their child's disrespect. The rabbis interpret this to mean the parents must speak literally with the same voice as though some divine entity is speaking through them.

And of course that's not possible so there is no record of any child being executed under that law.

And the justification for this radical interpretation is that "the Torah is not in heaven" [1]. Essentially this means that even if there is some divine indication that an interpretation is incorrect, it is irrelevant. God comes down to tell the rabbinate that they've made a mistake and the rabbis tell God that his opinion doesn't matter.

1. http://en.wikipedia.org/wiki/Not_in_Heaven

Adding a quick note here about Ramadan - the act of fasting and feeling hungry, thirsty, and tired also serves to invoke feelings of empathy with those who are less fortunate. Essentially, it is a reminder that there are always those who are in need. This is why muslims are encouraged to donate to the needy during this month.

Simply sleeping through the fast and reversing a sleep schedule seems to go against the spirit of the exercise. Of course, everyone fasts for different reasons and it is a very personal undertaking. I just wanted to clarify for those who may be thinking "Why bother doing it at all if you can flip your sleep schedule?"

Muslims around the world are going through the same materialistic tendencies as being seen all over the world. Instead of using Ramadan as a chance to cut back on worldly life and focus on spirituality, they are using it to focus on shopping, malls, entertainment, television, etc.. Fasting heightens the senses and brings an awareness to your mind about how we are only here for a short time. If you choose to sleep all day, I wouldn't call it a loophole, since you are not hurting anyone but yourself by sleeping all day during the fasting hours.

> If you choose to sleep all day, I wouldn't call it a loophole, since you are not hurting anyone but yourself by sleeping all day during the fasting hours.

Well, if you chose to eat, you also wouldn't be hurting anyone but yourself, so that can't be the relevant benchmark.

I noticed the same when I was in Kuwait several years ago. I remember going to a mall on day during Ramonda. Most everything was closed as we were on the way and most of the shops were just opening around 6 with sunset being around 7. After 7, the place was alive with activity.

same here, the malls open at 9:30 pm and close at 3:00 am, and they are crowded till at least 2:30 am.

While the author of the linked article expiates the hit coding performance can take when fasting I have personally observed an interesting phenomena during my observation of Ramadan. Namely, I can experience moments of acute lucidity and penetrating insight into a problem at hand.

Usually this occurs when I am in the midst of something that requires a good bit of effort such as tackling a thorny algorithmic conundrum or analyzing a particularly complex call stack. If I attune my mind to repress the pangs of bodily need I occasionally feel as if the external world melts away and I slip into an almost mystical state of oneness with the task at hand. Needless to say, I have been surprised immensely by this development.

One theory I have is that the blood flow that would normally be assigned by my body to the act of digestion is now free'd up to be reallocated to the ole cranium. Plausible? Unsure, but am certainly enjoying these life experiments!

Side note: for those observing the fast I have also noticed that my immune system is closely linked with the gut and my self-imposed starvations can lead to immune system compromise. Make sure you supplement your Iftar goodies with some replenishing nutrients such as pro-biotic yogurt smoothies rich in vitamin C and home-cooked chicken consomme.

I also tend to notice an increase in my productivity and ability to focus during Ramadan. A good breakfast is essential, I usually stick to yogurt, granola and vegetable juice - say my prayers then head back to sleep for a couple hours. I can't say I'm not hungry when 820 rolls around but I don't find the month debilitating and most of the time my co-workers don't realize I'm fasting until it's almost over.

I think probably whether you think you're abnormally better or abnormally worse at coding while fasting, you're just getting some placebo effect of whatever you're inclined to believe. I'm not sure what evidence there is that a little fast has significant effect on someone's ability one way or the other.

yes and also your liver gets a break. i normally experience the same a few hours after what would normally be my lunch time. Feel very light physically and find it easy to attune attention and really be creative. i do wonder if the lack of music/tv throughout the month also has an impact

>almost mystical state of oneness with the task at hand awesome

Very interesting, my experience has been slightly different this year.

Normally my brain is thinking 10 different things at one time. It is fairly difficult for me to focus (more so since I work at an office that has 5 TVs that I can see, and a couple of channels I can hear). The first few days of fasting, I was surprised how easily I was able to focus. Frankly I was far more productive than I normally am. Unfortunately, I've since reverted to the natural state of affairs -- I can no longer tune out TVs, youtube clips, etc.

In previous years, the first few days would actually be extremely difficult. I now realize that I was getting what is often called the "carb flu." This year, before Ramadan, I was on a low carb diet (Tim Ferriss' Slow Carb). Perhaps because of that, my body was already used to fewer carbs.

Hunger is not debilitating and if I could have water, I could probably 'fast' for 48 hours pretty easily (such fasting is actually recommended by the likes of "East Stop Eat" author Brad Pilon).

> The first few days of fasting, I was surprised how easily I was able to focus.

Back in olden times, the occasions when you haven't been eating are precisely the times to focus.

> Normally my brain is thinking 10 different things at one time. It is fairly difficult for me to focus (more so since I work at an office that has 5 TVs that I can see, and a couple of channels I can hear).

I think a part of the reason why programmers prefer working late hours (late as in after 12 in the night) is that the brain is sufficiently tired as to not be able to jump all over the place. You'd focus on one thing : Your code.

Or you think you are focusing on code, and just are too tired to notice context-switches or general slowness.

The illusion of productivity can actually increase productivity.

The feeling of gettings things done motivates. Even when that feeling is an illusion.

So what if it actually took 4 hours: if it feels like 30 minute, its easy to invest another "30 minutes".


Yes. I believe it helps with motivation, which for some people, like myself for example, is often the bottleneck of productivity.

Off course, others may have more intrinsic motivation, or just more discipline.

But if you are lazy like me, it helps a lot. Whenever i reach that point, i get into a zone, and just keep going and going. Im not working better, or more effectively, im just more motivated, and end up investing more time and effort.

You believe that the "illusion of productivity" brought on by fatigue can actually make you more productive than rest/sleep?

I've been trying one of the more popular Intermittent fasting protocols -Leangains for 20 days and counting. It was uncomfortable only for the first 3 days.

16-20hr (well-hydrated) fasts ended with a heavy lifting workout and BIG meal at 'breakfast' (6pm or later for me). FAQ: http://examine.com/leangains-faq/

I love it.

Increased alertness, focus, no more mid-day food comas. I'm a fat guy, so my body is probably fat-adapted after a couple weeks of IF.

And i work at my ghetto standing desk from 9 to 5 weekdays.

I can't imagine living any other way now. It's wonderful not to be a slave to food. I see food as just fuel now.

Note: I do take 10g of BCAAs before lifting heavy fasted. There is evidence that they prevent catabolism of muscle.

Any figures on how your body composition has changed over that time?

I don't have the resources to properly estimate and track BF%.

However, i've been tracking my waistline measurement every other day after doing my morning business and fasted. I seem to have lost 2cm since starting 3 weeks ago.

I'm inclined to not take this 'loss' that seriously because the consensus is that IF takes about 3-4 weeks to really start showing results.

On the other hand, i know i'm metabolizing fat; family members have been complaining of my new acetone breath. (ketosis!)

(Disclaimer: I'm a militant atheist now) I think I would find stopping five times a day for prayer to be a bit of a distraction, though I imagine the short bursts of meditation would be good for my concentration overall.

I tended to gain weight during Ramadan, but that's probably because my family made a big deal of every iftar, inviting extended family members, eating out and having big greasy Pakistani meals almost every night. I'm somewhat convinced that the type of food in my family would go towards explaining the early 60s life expectancy. Thankfully I married Japanese so I'm hoping that cancels it out!

I found fasting to be generally easy, even in quite long days in Saudi Arabia. Rather than hunger it was more the habit of snacking as a reaction to it that catches you out. The main tactic we had for dealing with it was (as much as possible) sleeping during the day and working at night, though I imagine you'd need a very understanding employer (or sufficient litigation) to pull that off as a full-time dev.

> I would find stopping five times a day for prayer to be a bit of a distraction

(Disclaimer: Not a muslim)

I think that is exactly what the prayers are for. They remind you that the only thing that matters in this life is submitting to God and to thank Him for His blessings.

Realistically you are stopping one time during the work day. Possibly twice if it is winter, due to the shorter days. All the rest of the prayers are timed outside of normal work hours.

> I'm a militant atheist

Oh boy those militant agnostics aren't going to know what hit them!

> Let’s just say fasting isn’t one of them. All of my co-workers; I have worked with past and present have been extremely understanding and respectful of the [month-long] fast. Also as a by-product of this kindness they have coined the term: "Ramadan code".

If I were an employer, after reading this...

> If I were an employer, after reading this...

There isn't much you can do; at least you can't make religious fasting the reason for your actions unless you are interested in lawsuits and tons of negative publicity.

What does it take to start a new religion? What if I start a new religion which says working more than 4 hours a day is against my gods? Can employers deny me jobs? Or if they don't deny it, are they bound to pay me full salary even though I work half the hours? If not, why am I being discriminated against when you are accommodating others(prayers 5 times a day, month long fasts, pregnancy etc).

> What does it take to start a new religion? What if I start a new religion which says working more than 4 hours a day is against my gods?

It would be somewhat easier to just start your own company if you wanted to work four hours a day. Though with a good marketing department, some cold reading and a truthy sounding manifesto I'm guessing you could probably pull it off if you wanted to.

> prayers 5 times a day, month long fasts,

IME, not many muslims outside muslim countries actually pray five times a day, and as demonstrated by this thread the ones that fast seem to do as much as possible to align their religious obligations with their employers interests.

> pregnancy

Why is this a problem? Would this extend to paternity too? It doesn't really count as discrimination in my book, as barring any social or biological obstacles in your path, applicable to you should you choose to have children.

If I were a full-time employee and by implication not independently wealthy, I would expect an employer to fund some time off to deal with babymaking. I think this is one of the primary benefits of being a full-time employee (especially since as I'm a consultant now, it costs five figures in potential fees to take two months off).

> It would be somewhat easier to just start your own company if you wanted to work four hours a day.

I do own my own company, and I work more than 4 hours a day. Let's say my religion permits working 2 jobs regardless of state laws(they permit multiple wives, multiple husbands. What's the big deal with multiple jobs), but you can work for more than 4 hours only for your company.

Let me try this:

The lord sayeth thou shall not work more than 4 hours; except for the company you have more than 35% stake in.

> IME, not many muslims outside muslim countries actually pray five times a day,

That's not the point. The thing is you are allowed to do so, and the employer doesn't have a say.

EDIT: So let's assume my religion is an exclusive one, and there is only one member - me. Does that mean I should be allowed to work 4 hours a day, come in drunk etc. because only a few people(exactly 1) does that; or else I shout persecution and give my life savings to a legal team.

> pregnancy >> Why is this a problem?

Sorry about that. That was my failed attempt at political correctness. My examples were particularly about Islam, and I thought I should include something non-Islam.

> What if I start a new religion which says working more than 4 hours a day is against my gods?

Then they'll pay you for four hours work. I don't think any law will force your employer to make unreasonable accommodations for you.

> unreasonable accommodations

Who is in-charge of making the call, and on what basis? What is to say working while starving is more reasonable than say, coming in drunk to work which my religion mandates. The funny thing with religious mandates is you can selectively choose the mandates. Someone whose religion dictates head gear isn't required to wear head gears whole of his life to contest that he should be allowed to wear head-gear while passing through a security check, or withdrawing from a CCTV monitored ATM, etc. My religion says you should work drunk; I can ignore it when I am not drunk and when I am drunk and called out on it, I will claim persecution.

These folks are my heroes http://en.wikipedia.org/wiki/Missionary_Church_of_Kopimism Someday I hope to start a religion whose sole purpose is to benefit people like me and is as unreasonable as I can get away with, because hell, why not. It's not like a lot of unreasonable behavior isn't already excused based on religious grounds(not particularly about fasts; I am talking about other extremities).

The judge will be in charge of that. If you have tons of money and very interesting case - nine Supreme Court judges, otherwise - probably your local court judge. And from what I heard, judges are not very tolerant to people that try to game the system and make fools of them, so you better be sure you are very persuasive with your new religion or you'll lose the case very quick.

It's not that simple. There's a few standards such as the beliefs being "sincerely held" and that accommodation should not render an "unreasonable burden" on the employer. You can say these are subjective but welcome the legal system. No judge is going to let a non-Abrahamic sham religion impose strange conundrums for the employer.

People have played games with this before. Some prostitutes have tried to make their business a religion and that sex with them is a "rite" of the practice. Others have tried to make their mansions be referred to as religious buildings to avoid paying property taxes, hasn't worked.


> You can say these are subjective

But they are subjective.

> No judge is going to let a non-Abrahamic sham religion impose strange conundrums for the employer.

What qualifies a religion as sham? From what I have seen, whatever complies with a religious person's belief is legit, everything else is a sham. People often love to mention scientology is a made up religion. No one ever explained to me scientology is made up as opposed to what?

> But they are subjective.

So is the application of most of our laws. I don't know what your point is. "Beyond a reasonable doubt" is the most subjective thing I can imagine but does that really matter?

The answer is, in reality and not in fantasy, NO.

> What qualifies a religion as sham?

If you made a religion that was "It is a commandment that one shall not be taxed more than 10% and that one cannot work more than 4 hours" it will be clearly seen that you do not "sincerely" hold that belief and that you are just trying to game the system and you will have put, under any normal person's view, an unreasonable burden on the employer.

This is a distinct question from objectively makes a religion a sham. We were talking about what you could actually get away with in the real world right? If that's the case then what I said is true and holds.

Now, if you want a defense of religion or why Judaism is any better than Scientology, you certainly won't get one from me. But if you try to play games and expect a judge to agree with you under EEOC laws, I doubt you will get very far. :)

If his employer decided they weren't okay with this, then yes, he might try to argue that it's discrimination. However, this argument would almost certainly fail, because he stated, in writing, that fasting severely impairs his job peformance.

"What does it take to start a new religion?"

Well if you are in the US, the religion has to be recognized by the government. If it isn't recognized then you would have no protection.

a) you're entirely correct

b) I always laugh at this because our Constitution doesn't talk at all about "freedom of religion" but it does explicitly mention "Congress shall make no law respecting an establishment of religion".

...which is exactly what the current practice is.

If you want to start a new religion, be prepared to spend an awful lot of donation money on a crack legal team who can defend a) your religion from anything that looks like defamation and b) your adherents from anything that looks like discrimination.

I am aware of the fact that whatever you can get away with(what you do doesn't affect others, legal team, political pressure, terrorism) becomes reasonable after some time. Religion is just a ruse. It's not that people adhere to everything their religion tells them to. Gay bashing, female subjugation etc. are just bigoted assholes hiding behind their religion and projecting their limited, hateful world view on others.

"You don't get rich writing science fiction. If you want to get rich, you start a religion."

If I were an employer, after reading this, I would encourage my observant Muslim employees to change their schedules and work at night, and from home if possible. Not every job can accomodate this, but many can.

Yes, that would be the legal lesson to learn from this. :)

I'm fasting and coding now - I really don't see a drop in code quality. Nor have I noticed it in others who have been fasting at the time.

We all seem to look for externalities to explain bad performances. Maybe the code wasn't very good, or the design not conducive to writing good quality code?

I suffer mainly from the caffine withdrawal. But this is good in a sense. By the end of Ramadan, I typically rid my system of a lot of junk that I'm used to putting into my body. Also, the effects of "performance enhancing" chemicals not being there also means you just have to work harder at what you do. While this may be hard in the beginning, it gets much better as time goes on.

Despite all of this, I know all about Ramadan code. After 5pm my blood sugar drops low enough that I can barely write a line of code without introducing serious bugs or typos. So, I try to get most of the coding done in the morning.

Fasting is actually very healthy. Not drinking any fluids, not so much.

I drink 3 glasses of water in the early AM meal + 1 glass of milk and then 4-6 glasses in the evening. I even fit in a light workout before breaking fast in the evening. So, dehydration isn't too much of a issue (at least if you're working indoors).

On the other hand, I find myself a lot more focused and productive in Ramadan.

Knowing that I'm not supposed to eat or drink, I don't have to think every other hour what should I gulp down my stomach. This is a distraction which is a bit difficult to get rid of in normal days.

Also, meal timings become strict which automatically instills disciplines. In normal routine I would adjust the meals by few hours just to get some part of code done. Having such flexibility also allows some buffer to visit Social Media or Hacker News. However with empty stomach, one stays relatively bound to complete the work rather than procrastinating.

EXACTLY my thoughts. The reduction of snacking distractions and washroom breaks has always been a productivity boon for me in Ramadan. Nothing to do but pray and code. I love it.

I agree. i become much more disciplined and frugal with my time in Ramadhan and often experience higher bursts of productivity.

There is quite a lot of science and study behind fasting, and it can actually be good for your health. I say this as someone who does a caloric fast (read: no caloric intake at all, fluids allowed) 6-7 times a week for intervals of 16-20 hours, in addition to my 3x weekly heavy weightlifting programme and my full-time job as a programmer/devops.

As of right now I'm the healthiest I've ever been in my life (physical strength and cardiovascular health), and my mind is as sharp as ever, especially when I'm fasting.

Could you detail your diet and exercise routine? I'm new to intermittent fasting and could use a little bit of advise.

biohacker Dave Asprey publishes had developed "The Bulletproof diet" around these principals (and a lot of others). He's selling stuff, but also gives a ton of advice for free. Google it if you are interested.

Sure. It's incredibly simple, even if there are a lot of concepts to grasp.


The macro-nutrient decomposition I tend to follow can be calculated for your bodyweight, height and level of physical activity here: http://www.1percentedge.com/ifcalc/ . Note that your level of physical activity is most likely sedentary, even if you plan on exercising. The higher levels are for people who have physically demanding day jobs. The rest/workout split toggle in the top left of the "Macro Calculator" tab will give you different total caloric requirements based on if you want to gain/lose/maintain weight. Remember: a ~500kcal/day deficit from your TDEE (total daily energy expenditure) translates to losing 1 lb/week, and vice versa for a caloric surplus. You can play around with the 4th tab to see what goes on.

The tl;dr version of this calculator is basically: eat more carbohydrates on workout days, and eat more fats on rest days. Eat 1g of protein per lb of body-mass on all days, and try to hit your daily caloric goals on all days.

Meal Timing:

Here's a typical day for me:

    * 6:30am. Wake up. Do morning things.
    * 7:15am. Take 10g of BCAAs with water, 4000IU of Vitamin D, and 10ml of concentrated (high levels of EPA/DHA) fish oil.
    * 7:30am. Take public transport to gym.
    * 8:00am. Double-shot of espresso. Sometimes I skip this - I purposely cycle on/off of caffeine every few weeks.
    * 8:15am. Start exercise routine. Lift heavy things. Lasts about an hour.
    * 9:15am. Finish workout. Ingest 10g of BCAAs.
    * 9:30am to 2:00pm. Work.
    * 2:00pm. First meal of the day. No significant calories (< 50kcal) before this.
    * 6:00pm. Second meal of the day.
    * 9:00pm. End of caloric intake window.
    * 11:00pm. Bed time.
For rest days, I skip the BCAAs and the gym (obviously).

Of course the above isn't written in stone, and sometimes I break my own rules by going out with friends, having a drink or two past 9pm, and so on. But you get the general idea.


Lift heavy things, and perform compound movements. My exercise regime consists of heavy squats, bench press, standing overhead press, Pendlay rows and deadlifts. Any other exercises are incidental, and I try to avoid muscle-isolating exercises in general.

I would highly recommend reading Starting Strength by Mark Rippetoe (even though some disagree on his precise methodologies, it's still the best introductory book out there), and perusing the http://stronglifts.com site as well. Once you've gotten past the point where those programmes are effective (which will take months, if not a year), there are many intermediate to advanced compound-lift based programmes that you can switch over to.

Sorry for the long post. I could go on for ages about this stuff; it's incredibly interesting, and is actually quite formulaic. If you eat what you're supposed to eat and do the exercises you're supposed to do, your desired results just... happen. Makes the scientist in me very happy ;-).

[Edit: formatting]

Fittitor, I take it?

Indeed – I try to avoid the hive mind (when it isn't backed by science) and form my own opinions, though. The great thing about personal fitness and nutrition is that everyone has got a great laboratory at their disposal at all times.

For those of you who feel clear-headed after fasting for a day or two: you might have a delayed food allergy (google "IgG food intolerance"). The most common such allergies are to gluten (not just coeliac sufferers are sensitive to gluten) and dairy products. I believe these delayed-onset allergies are fairly common in western societies, and are due to a "leaky gut", or permeable intestinal lining, that results in an immune system response when those foods get absorbed. Because IgG allergies can manifest themselves up to three days after you eat the offending food, some people may never figure out the cause of their fatigue or foggy-headedness. IgG allergies might be worth looking into if you have those symptoms.

Fasting helps me stay focused. I wake up at 8:30 am and have my first meal at around 4pm-5pm, and I just don't get hungry, and the lack of blood sugar level spikes doesn't get in my way.

I think I have always been better when I'm slightly hungry. When I'm satiated, I don't do much of anything.

IANAN (I am not a nutritionist) but I strongly suspect that the physical and mental exhaustion is primarily related to dehydration (as Mahdi Yusuf himself indicates by bolding "drink"). Looking at some of the comments here, the main difference between those who describe positive experiences with fasting and what the author describes is that the former drink water throughout the day. In that light, let me quote from a very good article [1]:

A normal average human body is made of approximately 60% of water. Water is the natural transport fluid involved in all important communication networks of the body. Drinking a lot of water (medium to low mineralization) ensures that the organs responsible for filtering and cleansing have sufficient carrying capacity and can eliminate toxins and wastes. You can see the argument as just plain good sense that we need sufficient water for dilution of wastes. Chemists and physicists know water as a truly exceptional fluid on many accounts. It is not by chance that life emerged and organized itself with water. Water is the best solvent that can dissolve an astonishing number of solid substances. Dehydration is a dominant cause of tiredness, pain and chronic diseases. Drinking about two liters per day plays marvel to keep energy and remove fatigue. Indeed, unknown to or often forgotten by the public is the fact that many chronic diseases may be associated with an insufficient intake of water. Such a simple gesture as drinking water regularly during the day may go a long way towards avoiding fatigue and remaining healthy.

I emphasize drinking pure water and not sodas, cokes, processed juices, coffees and so on. Just plain water. The drinks that are processed by agro-business are in general provided with added sweeteners that are known to promote malignant cell growth [Servan-Schreiber, 2009]. In addition, drinking with sugar (glucose, saccharine) prevents the body from strengthening its metabolic pathway of storing fat in time of surplus and burning fat efficiently in case of need. By feeding our body continuously with sweet drinks and sugar, we saturate our blood with sugar and we weaken considerably the metabolic processes of storing and retrieving sugar, making us more vulnerable to hypoglycemia in the rare cases where external sugar intakes stop. The consequence is to easily feel weak and tired. In contrast, letting the body be just flushed by plain water for hours ensures the build up of its metabolic capacities to burn fat efficiently. This is like muscle build-up by training. Art de Vany [2010] develops convincing supportive arguments for this. He correctly argues that our body is basically inherited from our hunter-gatherer evolution and we are thus adapted to strive in a patchy and varying environment for which our metabolism has derived efficient solutions to the energy flow problem. This backfires with our modern caloric and sugar rich, but nutritionally depleted, foods that are available at little expenditure of energy [de Vany, 2010], in the form of chronic diseases, an on-going so-called epidemic of obesity and many other modern so-called developed country diseases [Campbell and Campbell, 2006].

For the determination of the amount of needed water, a rule of thumb is to keep urine transparent. Do you feel a bit tired? Drink water. The effect is almost instantaneous. I constantly keep one or two liters on my office desk and drink when I feel like it and outside meals. I always carry water with me on trips. A minor nuisance is to drink it all before going through airport security._

_Of upmost importance is to drink our water outside meals. Most people use breakfast, lunch and dinner times to fill their body with both the liquid and solid nutrients that their bodies require. This is logical since meals are the times when we re-fuel our body. However, this behavior constitutes a fundamental mistake. Ponder this question: what other mammals in the whole animal kingdom drink their water together with their solid meals? None! We are the only one among about 5500 known mammal species who do it. The convenience of tools and the development of technology have put bottles on our meal tables to consume at the same time we ingest solid food. This apparent gain of civilization collides against a healthy diet for at least three reasons:

(i) Drinking lubricates and help swallow insufficiently chewed morsels; but digestion in the stomach requires the comminution of our food into particles that should be as minute as possible in order to maximize surface over volume ratio and therefore facilitate the digestive chemistry performed by the gastric secretions. This is just plain and simple good sense chemistry. When digesting unbroken food morsels, the stomach and the whole digestive system has to secrete more, takes more time to process our food, all this cumulatively increasing tiredness and fatigue on the body over the long run. I therefore recommend chewing so that you “drink your food”. Similarly, water and liquids should stay a while in the mouth before swallowing to warm up and mix with saliva so that you “eat your drinks”. A difficult digestion starting in the mouth is probably significant contributor to the feeling of tiredness after a meal.

(ii) Starch and other vegetable substances start their digestion with the help of enzymes found in the saliva; lengthy chewing ensures optimal chemical reactions with these enzymes and saves energy for the rest of the process in the stomach and intestines.

(iii) Ingested fluids dilute the stomach secretions, thus hindering the digestion process. Again, plain and simple good sense chemistry.

The article was originally written by a true scientist for his Ph.D. students. I think the physical dangers of our work is quite similar in that programmers and phd candidates or scientists will tend to get absorbed in front of a screen, sit for too long at a stretch, forget about or get negligent about food and drink, etc etc. I recommend this article.


[1] D. Sornette. Optimization of brain and life performance: Striving for playing at the top for the long run. Schweizer Monat, pages 38–49, Dec 2011.

(I believe the article is available on Arxiv.)

Yes, fasting really isn't bad if you drink plenty of water. I fast and pray semi-regularly (I'm a Christian). It is rough at first but you get into the groove about half-way through the day. Fasting never hurt by ability to code. Fasting sharpens sensitivity; my body kicks into "prayer" mode and I can focus better. On the other hand, it is really hard to fast and stay up late! I usually end up going to bed early.

As a former wrestler, I have had very similar experiences. On days where I could drink water, I assessed no difference in my productivity between days that I fasted and days that I ate, except when my fasting lasted over three days. Even then, my decline in productivity in relation to the duration with my fasting was not very steep.

However, I found that my productivity is very strongly correlated with my hydration, and going an entire day without water showed immediate, significant, and negative effects. I strove to manage my time in such a way to get all my work done without needing to spend those days programming.

Everything that Didier Sornette writes is worth reading, if you can understand it. His explanations are very clear, yet quite terse.

If you are into mathematical finance, geophysics, modeling of economics and/or social phenomena, complex systems (especially with respect to catastrophies), go read Sornette now.

The reference from the parent is his only "philosophical" publication as far as I know. Does anyone know of any others?

I recently grabbed a metal water bottle from a startup event. For the past week or so I've been drinking a full water bottle every hour or so. Totally anecdotal, but I've felt more productive and less exhausted, even as I've largely cut down my caffeine intake.

Hi, HN readers!

As a Christian I would like to tell you my opinion on this subject. Very often people tend to forget that fasting differs from dieting. Hence, there are all these advices on various "tricks" and "optimizations" :-)

What is missed here is that when you are fasting - you are not trying to reduce your body weight or improve your mental abilities :-) In fact, the fasting has nothing to do with you - this is done by you only to praise The Lord, who has created you, is looking after you and forgives your sins.

And if one finds fasting too hard and starts making a shortcuts, it is better not to fast at all - there will be no value in this "eating trickery" for you :-) (or anyone else).

The fasting is all about God and He gives you the strength to fast - but you need to ask Him by praying, reading The Bible, caring about your brothers and sisters, helping other people, giving to poor. And if you find fasting too hard - most probably you are trying to fast for wrong reason or your dieting has nothing to do with The Lord.

Personally, when fasting four times a year, I try doing good Christian things - helping people around me, charities, those in needs. Trying to put my own interests even further away, making peace with enemies, asking for forgiveness of people that I hurt somehow. Working on my project "Read and Think: The Bible for command line people" :-)

This is what fasting is for me and these are my "special tricks" :-)

The best source to read about fasting is The Bible:

................ == THE GOSPEL ACCORDING TO SAINT MATTHEW == ................... === Chapter 6, Verse 16 === 16 Moreover when ye fast, be not, as the hypocrites, of a sad countenance: for they disfigure their faces, that they may appear unto men to fast. Verily I say unto you, They have their reward. 17 But thou, when thou fastest, anoint thine head, and wash thy face; 18 That thou appear not unto men to fast, but unto thy Father which is in secret: and thy Father, which seeth in secret, shall reward thee openly.

Thank you,

How about life without nonsensical ancient superstitions? I am very much not being purposefully offensive when I say that. The initial premis of needing to fast is highly flawed when looked at rationally.

I know this is the complete opposite for most people, but my experience fasting is very different. for some reason (maybe someone can help explain why?), I find that while fasting I actually become significantly more productive and enter a state of extreme mental lucidity. the best way I’d describe it as is being on a high-dose of adderall (if you aren’t a regular user), but with a clearer head.

this usually kicks-in after the second day of fasting and stays pretty consistent throughout the month. I really feel it peak at about midway through my conscious fast each day (about 7hrs after waking-up) and it lasts up and through the time I eat.

I should just note that, in case someone’s thinking this, I’m pretty sure it’s not attributed to some sort of increased spirituality or something like that (I’m not particularly religious; more-so fast as a personal challenge and use the opportunity as a sort of annual ‘reset’ to physical habits)

as for how my fast goes, I think it may be considered somewhat extreme compared to others I know: beyond a fairly large iftar (dinner) at around 8:30pm I don’t really eat much else; I still keep vegan when I do eat; never wake-up pre-dawn to eat (though I sort of subconsciously wake-up throughout the night and drink water); and I don’t change any of my habits outside my time fasting (i.e. still go to gym after dinner most days, still go out at night, still drink (alcohol), still wake-up early for work, etc...)

Don’t skip meals to save time. 5 good hours are better than 10 bad ones.

Can we apply this to sleeping too?

I fast everyday. By not worrying about food while I do web-development I've noticed not only am I less distracted and get more done, but I am also less tired because my body isn't diverting energy to digesting food. I'd get really sleepy after lunch usually.

I practice Intermittent Fasting. I typically fast for 16 hours and eat for 8. I've been doing it for about a year now and I love it.

I fast regularly and if you already on a low carb diet, then the transition is much easier on your body. I don't notice a a diminishing of mental capacity, but I do notice that I need more sleep.

There are a lot of things you can do to prepare for a fast. For example, cut back on caffeine, sugar and even salt in the days or weeks ahead of your fast. Also, gorging on food the morning of a fast is not really healthy and is a sure recipe for "Ramadan code."

There was a fantastic article on fasting in Harper's Magazine this past March that covers the history of fasting, "Starving your way to vigor: The benefits of an empty stomach." Sadly, you have to be a subscriber to read it online:


Fasting doesn't have to devastate your mental faculties. I actually find that it helps me focus, and I have started doing it a few times a year.

I'm currently on Ferriss' low-carb diet and I have found constant carb-withdrawal hard to bear on days on which I do much programming (basically every working day). There are some tricks though which help me keep up focus:

- MSM,

- Caffeine (less is more - just a sip of coffee, or half a cup of green tea; too much of it actually downs me after the first high),

- and regular consumption of "allowed" carbs (lentils being my favourite) and fat (peanut butter, olive oil,...). Native coconut oil is a real brain booster, I feel super-focused after having eaten a spoonful.

MSM does really do much in this regard for me, it feels as if it's helping my body renew its energy stores. I can go a lot further with less food when having taken it - and I do need to take it in order to seriously lose weight.

Eating nothing for more than 4 hours shoots my focus down for hours, and is hard to rebuild with low-carb food.

The carb withdrawal is only for like, the first week, right? Then you'll be scot-free! Or so I thought.

In low-carb diets, one of the major withdrawal symptoms is actually from a lack of sodium. Your body starts emptying it's water stores when there is no carbohydrate intake to process (carbs need a lot of water to work with), and that takes tons of potassium and sodium out of your body.

Eat or drink something with lots of sodium, and it should hep with the carb withdrawal symptoms quite a bit (the 'keto flu').

Here is my experience: I am in Egypt, and I decided to stop working at all in Ramdan's day.. I work only during night, because its very very hot here, which you start feel you need to drink by 11 am, and our stupid government keeps cut electricity during the day, so we can't even use air conditioning most of the time, because there is no electricity, and if you don't know, using air conditioning helps so much reduce the need of water.. which is the main problem in a very hot weather like in Egypt.

I spend all the day sleeping, and start working after Iftar.

HN is truly a community of many nations, cultures, religions, etc...

I changed my schedule for the past few days and it's working very well. I get home from work at 5 or so, sleep for 1.5 hours, get up and ready myself to break fast. Afterwards I am operational until 2AM. I eat several times during this period and I go to sleep, waking up again at 8-9. (Yes, you guessed it, I am still not able to make Fajr on time).

The above beats going to sleep at 11 or 12AM then waking up at 3:30 to eat before going back to sleep.

I personally can't relate to this specific religious practice however this is very similar to the feelings experienced when trying to quite smoking. The second time I tried quitting smoking I was unable to concentrate on my code which unfortunately drove me back to cigarettes for another three years. If you're a software developer it's even harder to quit (words of advice for anyone reading this that might be heading into college this coming fall)

That sounds like a lot of fun. I am glad I am not religious.

I have no problem with people having the right to do this type of stuff because I enjoy my right to laugh about it.

I started working out recently (about 8 weeks ago) and I'm now following this protocol: http://leangains.com

My energy is up, I'm loosing weight (I work out very morning) and feeling great. I do find that I'm having a bit of trouble concentrating, but is getting better everyday.

If I manage to concentrate as I did before using leangains, this is by far the best I've felt in years.

Have to say i've not suffered too much. I think it's a combination of what i choose to eat at fasting (suhoor) time, abiphasic sleep pattern and limiting sugar intake when breaking the fast.

I do a light sleep / nap for 2hrs at night, and then eat suhoor and make sure i stay awake for a fixed period of time before going back to bed. i wrote a dedicated post about this last year if anyone is interested.

I've fasted multiple times and it was straight days with only water. Never had any problems, in fact, I've always felt much better than before. I feel serene and can do my tasks just fine (or even better than before).

The author must be suffering from dehydration, not fasting.

Fasting appears in many of the world's religions. I'm curious about the roots of fasting that have been codified into religious practice. Did the ancients discover that fasting was good for you?

No, they saw that hunger is bad and nobody would want to go hungry voluntarily. Suffering for your faith, mortification of the flesh, self-flagellation, etc.

Certainly not a "Diet secret of the ancients", some beneficial side-effects are mostly accidental. (And to be honest, going hungry wasn't exactly hard throughout most history.)

But, well, we've got pretty deent beer out of it.

There are definitly modern (non religious) proponents that argue fasting <=20 hours has it's health benefits. Even buff fitness gurus.

But abstaining from water as well is not recommended. At least not in any material I've seen.

Good question. I think it's a hack: on the one hand it supposedly frees up energy from digestion to concentrate on prayer or repentance, on the other hand I don't feel the thinking is as deep: it locks one into a survival mode thinking - which may or may not help the spiritual practice. Like driving when tired: only the needed parts of the brain that are required switch on. So concentration improves, but the thinking is not as deep (that is when hunger pangs don't distract!)

Supposedly fasting also promotes longevity by affecting gene expression, and the same effects can be obtained from resveratrol. Additionally, small fasts are meant boost human growth hormone, hence the warrior diet: only eating at night. Fasting before and after exercise boosts it the most.

A doctor I once knew said the reason they put new doctors on such long shifts is so they stop thinking and behave more according to text book.

Anyhow, check out this article/podcast about a fasting, and in particular regarding someone grossly obese for 1 year and 17 days: http://www.abc.net.au/science/articles/2012/07/24/3549931.ht...

"His weight dropped from 207 kilograms to 82 kilograms. Some five years later, he had regained only 7 kilograms."

I wonder how mentally active he was during that time.

The fact that it was popular doesn't mean it was good. Bloodletting was an extremely popular practice too, but it's now a consensus that's it's harmful except in very specific situations.

Although people did bloodletting because they thought it was good for you.

Maybe it was a way to get people to ration food over winter?

In my case, it's ironic that I feel lethargic right after breaking fast (probably due to digestive system kicking in), while the rest of the day is a breezy peacefulness.

Fasting is a mental exercise rather than anything else.

Strangely, I usually put on more weight during Ramandan. I think it's a combination of work/food/sleep-pattern.

> Strangely, I usually put on more weight during Ramandan.

If you are starving, your metabolism slows down to conserve energy. I assume you eat heavy meals(high carb? sugar? oil?) when you break your fast(dinner? before morning prayers?). Slow metabolism, coupled with high calory intake when your body doesn't need it(if you go to bed after a heavy meal, what would your body use the calories for?) would be the reason for the weight gain.

Your body starts eating away at your muscles and storing as much fat as it can. That's why it's important to exercise.

Fasting is good for your immune system as it stimulates phagocytosis. Here's a paper on Ramadan fasting:


An amusing book on complete fasting by vintage american novelist Upton Sinclair here:


Personally, I fast regularly up to two weeks at a time, both for weight control and because I believe in it's overall long term health benefits.

Up to two weeks at a time of a total (water only) fast? I've done this before, but it was quite difficult to maintain in the midst of work pressures and I'm curious to know how you manage it.

I'm very interested in this. I've never tried fasting before -- and I'm 33 years old, which means I've had a lot of time to get used to eating a lot -- so I imagine that I would have a feeling of "starvation" that would be awfully distracting. Plus, I'm a bear when I'm too hungry and I wonder what I could do to avoid taking it out on the people who surround me (especially my 5 year-old kid).

I find that passes, as long as I've slept well, drunk enough (water) and am otherwise feeling fine.

I often go all day without eating while I work, and contrary to the OP and more in line with several of the other posters here I do find myself more productive, able to concentrate and focus, and feeling more energetic (I know it's counter-intuitive).

However the slightest inkling that I'm feeling worse for it, or that my productivity is beginning to slip, I'm feeling unusually tired - I'll simply eat. I'm not entirely sure losing much weight would be good for me (I don't have much to lose) and I'm not trying to take things to extremes. I just side with folk who agree that 3+ regular meals a day is not necessarily the only healthy way to do things.

Note well that this is all simply my own experience, and I'm certain people differ. I do this because I'm happy, comfortable and feel better for doing so - if you try it and don't, perhaps it isn't for you. I know I wouldn't do it if that were the case.

(not parent poster here, but here's my advice):

Drink lots of water. When you feel like you _must_ eat right now (rarely happens after day two), drink a liter of water, and go for a short 5 minute walk.

Also, add a few drops of freshly squeezed lemon juice to your water. The availability of flavor is often enough to get you through the hard 5 minutes (and after day two, it is rarely more than 5 minutes).

My experience is that even with lots of water you get serious muscle fatigue starting on day 4, and major dizzy spells everytime that you sit down/stand up. Also, the body seems to go into something of a hibernation mode and want more sleep. Besides those factors, I'd say I've managed reasonably well, and I think you could continue to work a desk job just fine -- but the inability to move quickly will kill any exercise patterns you have, or, potentially, the ability to do much more than 5 minute walks. It also makes it far more difficult to get out of bed in the morning.

Interesting. I guess it depends on the kind of exercise you do.

What I noticed is that around day 7 or so, anaerobic exercise (e.g., thai boxing) becomes very demanding and hard to keep up for more than a few minutes at a time. However, it's just as easy as always to do aerobic exercise like jogging or swimming.

Never had dizzy spells or feeling of muscle fatigue (except for anaerobic exercise) - and it was also easier to get out of bed in the morning.

However, a friend of mine noted that my body goes into a super-economic mode - that I hardly lift my feet off the ground when I walk (less than an inch on average), and that my arms seem to move quite a bit less.

I wonder if the insertion of lemon juice is enough to counterbalance the dizzy spells. I recall doing long walks but not any jogging while doing longer fasts.

I'm very surprised by the lack of muscle fatigue though. I've done fasts of 4+ days 10+ times and I always get significant muscle fatigue around that point (esp. in the hamstrings).

If the lemon juice does it, it's something other than the sugars - I didn't even use a whole lemon through 21 days.

Very curious now what causes the dizzy spells. Please send me a github message or something if you ever find info. This is a long term interest of mine.

>Also another little thing. This entire blog post was written using the dictation feature in Mountain Lion.

So that explains the mistakes in the post I was wondering about. For example:

>(not that I wouldn’t I love parks).

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