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Is fasting good for you? What we know so far (aeon.co)
56 points by blondie9x on July 24, 2016 | hide | past | favorite | 30 comments



The author went through keto flu, which is a series uncomfortable adjustments your body makes as it transitions from glucose fuel to ketone fuel (ketosis). People who begin ketogenic diets know this well. Fasting feels very similar. The most acute symptom is often "brain fog", which manifests exactly how the author described.

Ketosis takes several days to begin while the body burns through its reserves of glycogen, at which point the symptoms begin, then lasts several days while basic adaptation takes place. Full adaptation to match one's athletic performance while glycogen fueled can take months.

The author didn't even mention the words ketosis nor ketones, so I have to imagine she went into this quite blindly. Once you've gone in and out of ketosis several times, you don't experience flu symptoms nearly as much and sometimes (me) not at all.

For most people a fast starts to feel magical after about day 5, where keto adaption has taken place and the mental habit and craving for food starts to subside. Obviously this will vary from person to person, so maybe the author didn't quite get far enough along to get out of the woods, so to speak.


Strange, I feel that by day 3, I'm fully switched over, and in fact I get a bit of a mental boost; I'm /definitely/ sharper on day 3+four, and then it tails off.

Mind you my typical fast starts on sunday after supper, and finished most fo the time on friday before supper. I do that so it doesn't impact too much the social life etc...

Overall I don't recommend short fast. I feel you need at least 3 days for it to be worth it, otherwise you get the pain (hunger on the first day) without a lot of the benefits.

But then again I only have my own experience on tap; most people I know think I'm bonkers to stop eating for most of a week ;-)


I describe that as a carb hangover.

In fact, if you're eating a regular Western diet and feel faint before lunch and sluggish after, you can appreciate to what degree you're chasing your blood sugar around.

Switching to a diet with more protein and vegetables, and maybe "slow carbs" ala Tim Ferriss, you can even those highs and lows out and not feel them any more.


I've seen some exogenous ketones products, e.g. [1]. Could these help to get into ketosis without the nasty side-effects?

[1] https://www.amazon.com/KetoSports-KetoCaNa-Original-Exogenou...


The belief is "yes" but research on the topic is new and unfinished. Dr. D'Agostino specializes in ketogenic nutrition, and discusses exogenous ketones for exactly that purpose in two podcasts[1][2].

http://fourhourworkweek.com/2015/11/03/dominic-dagostino/ http://fourhourworkweek.com/2016/07/06/dom-dagostino-part-2/


> so I have to imagine she went into this quite blindly

*He


This article touches lightly on research in to one type of fasting (intermittent fasting), then proceeds to detail the authors' personal experience with a very different and more extreme type of fast (a one time 7 day fast).

I fail to see how this approach provides any value, nor does it even attempt to answer the question or provide the summary posed in the title.

This is a prime example of editorial incompetence in titling an article.


The title is "One week, no food". I don't see how that contributes to the problem.


The title (which can be seen in the slug and the HN link) was "Is fasting Good For You? What We Know So Far."


This is not "what we know so far" - this is an anecdote about one person and his wife fasting for a week. There's a cursory section about the current buzz around the topic, and then a reasonable account of what happened to them.

That's it. Nice story, no actual data.


I was thinking the same thing. It's become trendy to tack "What we know so far" on to article titles lately (especially editorials masquerading as news). The phrase is being abused.


By we, they probably just meant themselves.


In that case, how can they address the question "is fasting good for you"? They may as well write an article "can you believe your horoscope? what we know so far" based on their personal experience. This is exactly the type of topics where I'd like to have scientific data as opposed to personal experiences.


... which is misleading given what the term means to most English-speakers.

The point stands: it's a decent story with a crappy title.


My portion sizes are small and I eat ~8 times during the day. That being said, I’m still on a mild form of calorie restriction, I think. If I don’t eat for over 3 hours and then start some physical activity, I sometimes start to feel weak and sick. I don’t think I could function if I tried to fast for a whole day.


There's all this bro science about "if losing fat, you need to do specific things to avoid losing muscle in the same proportions"; I've heard a lot about the supposed health benefits of intermittent fasting, but nothing about its effects on muscle that seems remotely reputable. Does anyone here know anything about IF in a bodybuilding context?


https://www.reddit.com/r/keto/wiki/faq#wiki_tl.3Bdr

It's a good start point. You may need to get the kit to measure your ketones, a caliper to measure your fat body %, keep track of your weight, and eat properly (the most difficult part). Now what "properly" means is the most dificult part and that's were all the previous mentioned tools will help you; to determine where you are getting gains (if any) or you are getting to the shape you want. Keep in mind that after you get into some % you will have to start eating more fat in order to prevent muscle loss, check http://keto-calculator.ankerl.com/


Bodybuilders aren't really reflective of how humans work. While cutting they're usually on test/tren + t3/clen/dnp and may still be using gh/insulin timed around their meals. And, working out multiple times a day, then playing with their carb/sodium intakes.

It's probably healthier to be morbidly obese than what a pro bb will put their body through.


I didn't really intend to imply bodybuilding-qua-professional; merely bodybuilding-qua-programmer-who-lifts.


IF will work fine for the average person for a simple reason-- If you skip a meal and if you leave your other meals at the same size as before, then you have removed a few hundred calories from your diet and will lose weight for a while.

I've been doing IF for a while without trying to since I don't really eat breakfast and I really only eat lunch with my team because cooking dinner for 1 isn't awesome + delivery is too expensive.

It's okay for maintaining strength/losing weight slowly, but hunger/happiness on it really depends on the person. Some people don't do well with only eating 1 meal a day.


It can be done very long under certain conditions and with medical supervision http://www.abc.net.au/science/articles/2012/07/24/3549931.ht...


Does anyone have any good references to scientific research about fasting?

As others pointed out, this article is not it.


Original title: One week, no food


One person who has done good research on fasting is

Dr Valter Longo. http://gero.usc.edu/faculty/longo/


the Jain philosphy has been promoting annual 1 week water fasts for thousands of years.


> We bought some emergency supplies in case one or both of us ended up feeling ill or fainting: some energy drinks, a couple of bars of Swiss milk chocolate, some fruit, and some bread and cheese, and put them in the refrigerator.

> My wife and I don’t normally eat breakfast (she has a cup of coffee and I drink a Coke Zero — yes, yes, I know it’s bad)

Fasting releases toxins into blood stream. If you eat junk food before fasting, it will cause headaches and other nasty stuff.

Better is to start slowly, eat vegetables / rice for a month, than start fasting.


> Fasting releases toxins into blood stream

Nonsense. What 'toxins'? Where are these 'toxins' from? What are there effects on the body? What scientific papers detail these 'toxins', their chemical makeup, source, etc?

'Toxin' as a word has become a high-level indicator of pseudoscience and homeopathy-style unscientific health advice. If you see someone using that word, always question or ignore their advice. It's the 2000s version of the Victorian era 'impurities' which were leached or vomited from the body to return to health.


It's possible that parent is referring to the mild acidosis that can accompany ketogenic diets or fasting. At some point along the process of using fat, rather than glycogen, for fuel, your body's compensatory mechanisms (bicarbonate buffering, renal excretion, and a few others) can't keep up with the acid in the blood stream, causing a lower pH.

I'm not going to take a guess at 'toxins.' When I hear that terminology, I think of a blindfolded kid trying to hit a pinata with a bat, or carpet-bombing: they'll get there eventually if only by the imprecision of their targeting, but it's not pretty.


Yes, fat burning releases 'toxins' which are accumulated there. It is a problem when fasting for extended periods (week+).


I don't agree, at all. I'm French and I love food, and cooking. I treat myself to a super meal before I start fasting... Never had a headache! I try not to hit the bottle too much tho, there's nothing worse than a hangover at a time you /can't/ eat ;-)

As for emergency supplies; on the contrary; just CLEAR the fridge, remove any temptation. I usually prepare/buy meals for my wife, but I try to make them quick to prepare and not too smelly. No need to torture myself smelling her lovely little dinner ;-)




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