
Fasting Affects the Brain - laurex
http://www.brainfacts.org/thinking-sensing-and-behaving/diet-and-lifestyle/2018/how-does-fasting-affect-the-brain-071318
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ravenstine
I sometimes intermittently fast for 24 hour periods, but recently I've
switched to skipping breakfast, which effectively works out to be a 17 hour
fast for me if I eat dinner at 6pm and have lunch at 12pm. Everyone says it's
the most important meal of the day, but I haven't found convincing evidence of
this(especially that which isn't sponsored by grain and sugar producers), and
not having a huge insulin spike at the beginning of the day seems beneficial.

The results are profound. I'm a lot more focused and emotionally stable. The
only distraction is the frequent "gotta find food" feeling, but that usually
subsides within minutes. It's usually not even true hunger, but an impulse
instilled in me by a culture focused on eating and "never starving".

Pro-breakfast proponents say that eating breakfast results in eating less
throughout the day, but I can't say this has been true at all for myself. When
I ate breakfast, I also would snack more throughout the day. Without
breakfast, I look forward to meals more and those two meals, which are almost
always ketogenic, are more satisfying.

The only negative effect I'm having is that my sex drive has plummeted to
near-zero. I suppose that's a good thing for focusing on work, but I wouldn't
want to keep that up forever.

~~~
UpperBodyEimi
“Breakfast is the most important meal of the day" was an advertising slogan
for Kellogg's.

~~~
tw1010
That sounds plausible (and interesting) but do you have a source for it?

~~~
Reedx
[https://youtu.be/9Ffceu672c4?t=173](https://youtu.be/9Ffceu672c4?t=173)

Dr. Kellogg and his brother had a business creating various supposed health
products and Corn Flakes was part of that.

In 1917 a magazine called Good Health, edited by Dr. Kellogg, wrote "in many
ways breakfast is the most important meal of the day". That seems to be the
origin and cereal makers ran with it.

~~~
dragontamer
> Dr. Kellogg and his brother

More importantly, Dr. Kellogg and his brother started two rival companies. The
brother believed that sugar should be added to the formula Dr. Kellogg has
been using to treat his patients.

Dr. Kellogg refused, believing sugar to be awful for the body.

Needless to say, we all know which of the two rival companies became the
corporate giant, and which of the two rival companies disappeared into
history. There was a big court case between the two rival brothers over the
"Kellogg" name. After that, the two brothers never talked with each other for
the rest of their lives.

[https://en.wikipedia.org/wiki/John_Harvey_Kellogg#Breakfast_...](https://en.wikipedia.org/wiki/John_Harvey_Kellogg#Breakfast_cereals)

Since the two were brothers, it is somewhat ambiguous to who really invented
modern cereal. But Dr. Kellogg was the health-fanatic who would have been
studying "healthy breakfasts" and other such stuff.

EDIT: It should be noted that 1890s / early 1900s medical science was
downright awful. So definitely take any health claims from that era with
suspicion. Be sure to look up "sanatoriums" and how awful their medical
practices / beliefs were. There's probably a nugget of truth somewhere in Dr.
Kellogg's research, but you've gotta look at his claims through the lens of
history to really understand him.

------
hashberry
> And that’s what we’re finding in lab animals — the brain and body actually
> perform better during fasting. In the case of the brain, cognitive function,
> learning, memory, and alertness are all increased by fasting.

I find this to be true whenever I fast for 12+ hours. It feels like I'm on a
drug.

It's strange to realize how not eating can be good for you.

Fun trivia: the longest a human went without food is 382 days. [0]

[0]
[https://en.wikipedia.org/wiki/Angus_Barbieri%27s_fast](https://en.wikipedia.org/wiki/Angus_Barbieri%27s_fast)

~~~
magnamerc
I've done 7 day water fasts (I try to do them quarterly, or bi-annually) and I
find by day three I'm full of energy to the point where I have a hard time
sleeping. I'm also way more productive during those 7 days. The only thing
that tends to suffer is my weight lifting. I drop in strength a tiny bit, but
not nearly as much as you'd expect. I also drop about 5-10 lbs in mass, with
about half of that coming from water. Almost no lean muscle loss as far as I
can tell. In fact, I always look shredded after the fast. I just ease back in
with keto for a week or two, then back to low carb diet.

~~~
ohaideredevs
Being hungry increases alertness. This is discussed in "The Willpower
Instinct", in the context of keeping you from sleeping well. It's natural -
the body knows it needs to find food, so it makes you hyper until you do,
negatively affecting the ability to get essential sleep.

So, there is nothing weird about what you are experiencing - it's like wanting
to get air when you are under water. Doesn't make it a good way to do things.

It's amazing how much of a trend fasting is lately.

~~~
magnamerc
Yeah I'm aware of the biological reasons for why I feel the way I do when I
fast. There's a lot of science backing why fasting is good for you, and it has
to do with mTOR and the science behind apoptosis, for which Yoshinori Ohsumi
won the nobel prize in 2016. Fasting isn't a 'trend' like say 'cleansers' are
a trend. One is backed by science, and the other is just a catch phrase to
sell products to people.

~~~
ohaideredevs
The question is of balance. For example, if fasting keeps you from sleeping, I
consider it an issue. If fasting causes muscle loss, I consider it an issue. I
read the cancer research - how much is damage is being done by not getting the
nutrition you need though? It's still a trend - there is no balance defined.

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istjohn
I wonder how these findings can be reconciled with the research on the
importance of breakfast for school children. There are obvious differences
between the two issues, but nevertheless when I think about how to apply these
insights, they seem to conflict, and I'm not sure how to resolve those
conflicts.

Edit: The biggest difference is age, but conventional wisdom says adults, too,
should eat a good breakfast before an important exam. Should you skip
breakfast before your LSAT?

~~~
magnamerc
If you want to ace your LSAT, you're better off getting a good nights sleep
and writing the exam fasted. Sleep is way more important than anything else
when it comes to memory recall. Also, you should study with a particular type
of perfume, and then write the exam with that same perfume. That'll also help
memory recall. Breakfast is probably the worst meal of the day, in terms of
metabolic health, which is why I haven't regularly had breakfast in over a
decade.

~~~
graeme
I agree, except It would recommend people fast regularly before test day so
the body is adapted.

I teach the LSAT and I'm astonished how some people try to do it while sleep
deprived. In their regular studying too.

(Day before test nerves can impede that night's sleep, which is really
unfortunate)

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tmysl
[http://webcache.googleusercontent.com/search?q=cache:YXae0gV...](http://webcache.googleusercontent.com/search?q=cache:YXae0gVGTJoJ:www.brainfacts.org/thinking-
sensing-and-behaving/diet-and-lifestyle/2018/how-does-fasting-affect-the-
brain-071318+&cd=1&hl=en&ct=clnk&gl=us)

~~~
RenRav
Thanks, I was having trouble on my phone accessing the site.

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mcfunk
Interesting that this is "news" when the medical understanding of fasting and
ketosis is pretty far along.

Highly recommend the book "The Complete Guide to Fasting" by Dr. Jason Fung.

When you think about it, while the "naturalness" argument is always suspect,
it's very odd that humans eat as often as we do in the US, and unsurprising
that negative health consequences follow (and positive health consequences
follow fasting).

~~~
coldtea
> _Highly recommend the book "The Complete Guide to Fasting" by Dr. Jason
> Fung._

Such books and doctors, promoting this or that diet, heavily cherry-pick from
research papers, they don't reflect the scientific consensus on the matter.

~~~
mcfunk
I'll be interested to see where the scientific consensus is in 10 years. I
think the evidence is very much on the side of the hormonal theory of obesity
and fasting, especially given the monumental failure of the "calories in
calories out" model.

~~~
wyldfire
> especially given the monumental failure of the "calories in calories out"
> model.

Can you explain this in more detail? CICO seems like it might oversimplify
things but it always seemed like a really sane basis for helping shape your
diet. If you need to lose weight, you should plan meals to create a calorie
deficit. But yes, I would not be surprised to learn that fasting on day X and
consuming double your normal calories on day X+1 are not equivalent.

The description of CICO as a "monumental failure" sounds like there's
substantial evidence to the contrary -- can you share more info?

~~~
qntty
This article makes a case against a calorie-centric approach to dieting. It
boils down to something like Michael Pollan's "Eat food, not too much, mostly
plants." A guy (who has since become an expert in public health) wasn't able
to control his weight using standard calorie-counting techniques and had a lot
of success changing his diet to "high quality" (as opposed to "highly
processed") food. The article isn't super clear on specifics of what that
means but it sounds like there might be something to it. Also worth noting
that he began exercising in between this switch.

[https://www.1843magazine.com/features/death-of-the-
calorie](https://www.1843magazine.com/features/death-of-the-calorie)

~~~
AnIdiotOnTheNet
Eh. the articles argument appears to be that even though nutritionists,
physicists, and dieters all agree that eating fewer calories than you expend
causes weight loss, it isn't easy for a variety of factors. No shit. The thing
is, it is the simplest expression of what needs to happen, and there is no
getting around it.

I was once well north of the weight of the subject in the article and have
since shed about half of it and kept it off for years. I've been through all
the games your brain and body play to try and get you to eat more, and all the
fad diets out there sound to me exactly like those games. It's nice to believe
you don't have to suffer to reach your goals, but it isn't true and anyone
telling you otherwise is trying to sell you something.

~~~
mcfunk
There's also good evidence that people don't maintain that weight loss over
time despite maintaining their lower calorie consumption. Because base
metabolic rate is something that the body can adjust, just like if you had
less money to pay for heat, you could just put less heat into the house.

The role of hormones (especially insulin) in regulating fat storage and
whether stored fat is available to the body as energy is better understood
now, and much has been documented about how high insulin combined with low
calories over time results in a lowering of the metabolic rate (resulting in
stalling weight loss and then weight gain) rather than sustainable weight
loss.

Also "it's nice to believe you don't have to suffer to reach your goals" is a
silly and moralistic thing to say. But it typifies the american "scientific
understanding" of weight loss. Fat is immoral, suffering is virtue, therefore
in order to lose your immoral fat you must suffer.

Just look at all the massive success of those in the IF and keto community in
living joyful lives, not deprived, losing fat etc. etc. And then look at all
the people for whom calorie counting has completely failed. The information is
out there (shruggie)

~~~
coldtea
> _There 's also good evidence that people don't maintain that weight loss
> over time despite maintaining their lower calorie consumption. Because base
> metabolic rate is something that the body can adjust, just like if you had
> less money to pay for heat, you could just put less heat into the house._

Well, it's not just some fixed calorie amount they need to take for an
eternity. It's the amount that corresponds to their current weight and muscle
mass. As those change over time (and their base metabolic rate changes), they
should change their calorie target too.

> _Also "it's nice to believe you don't have to suffer to reach your goals" is
> a silly and moralistic thing to say. But it typifies the american
> "scientific understanding" of weight loss. Fat is immoral, suffering is
> virtue, therefore in order to lose your immoral fat you must suffer._

Actually the 'silver bullet' is more typical of the american "understanding"
of weight loss.

There's no silver bullet. No pain, no (weight) loss.

~~~
mcfunk
LOL ok, so "eat a diet and time your eating in a way that promotes healthy
hormone balance and use of fat as energy" is a silver bullet but "use our
magic equations based on state of the art info from 1958 to calculate your
daily food needs and all your food and exercise as numbers and if your
equation balances you'll lose weight" isn't. Sure.

~~~
coldtea
> _" eat a diet and time your eating in a way that promotes healthy hormone
> balance and use of fat as energy" is a silver bullet_

If it promises you to lose weight without limiting your calorie intake (e.g.
have your weight loss cake and eat it too), then yes.

> _but "use our magic equations based on state of the art info from 1958 to
> calculate your daily food needs and all your food and exercise as numbers
> and if your equation balances you'll lose weight" isn't_

The laws of thermodynamics don't change because we don't have good formulas to
calculate the exact amount of calories a person has a basic metabolic rate
just based on their weight and height...

Calories still matter, and you should still limit your intake -- whether you
do it approximately by "state of the art info from 1958" or with modern
medical tests and expensive equipment. Or you know, just with eating less that
you normally do, even without counting calories (if you ate 1 steak per day,
and you change it to 1/2 a steak, you're eating half as much calories, even if
you don't know how many exactly). Skipping BS deserts will cut even more...

No great science required, millions of people have lost way by just eating
less...

~~~
kazinator
Some people don't want to lose "weight", but "fat" (often specifically
"subcutaneous fat", often from some specific body area).

If you're already very fit and lean, but have some stubborn fat around the
"love handle" area or elsewhere, "eat less" doesn't cut it any more. Sure you
can reduce that area, but not completely, and while the rest of you turns into
an ugly skeleton.

~~~
coldtea
> _Some people don 't want to lose "weight", but "fat" (often specifically
> "subcutaneous fat", often from some specific body area)._

The latter people are then delluded, surgery aside, you can't lose targeted
fat from a specific body area. You lose fat across your body AND from that
area, or you don't lose fat.

At best, you can trait that area and build some muscle next to the fat.

------
virtuexru
Intermittent fasting changed my life. I've quit coffee, eat way healthier and
generally feel better & have a uplifted outlook on life. I'd definitely
recommend the Zero app. I do the 13 hour fast but sometimes will go up to
15-16-17 hours whenever possible. Also don't forget to take a cheat day every
now and then!

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Zaak
Fasting is a periodic religious observance for me. The main effect I have
noticed is increased irritability, but then I've never done cognitive tests
while fasting.

~~~
throwaway123x2
That might be from the caffeine withdrawals. I'm trying it wihtout caffeine at
all this year, and it's been great.

~~~
jawilson2
Or, a carb-heavy diet. When I fast while doing keto, it's almost not
noticeable, and I'll often just forget to eat and suddenly realize I haven't
eaten in a day or more. If I've cheated on carbs and try to jump back into
fasting, I'm ready to commit murder after 10 hours.

~~~
Zaak
Thanks for the info. I tend to have a carb-heavy diet. I wonder if doing a
low-carb diet for a couple days before fasting would help. Or do you think it
would take longer than that to acclimate?

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mrspeaker
Seems like the link is dead. Anyone have a summary (or cache)? I've been
thinking of fasting, just to test it out - but it's hard to research as a
topic because there is so much pseudo science and so many "miracle diet" blogs
out there.

~~~
neves
Cached text version:
[http://webcache.googleusercontent.com/search?q=cache:YXae0gV...](http://webcache.googleusercontent.com/search?q=cache:YXae0gVGTJoJ:www.brainfacts.org/thinking-
sensing-and-behaving/diet-and-lifestyle/2018/how-does-fasting-affect-the-
brain-071318&client=firefox-b-d&hl=en&gl=br&strip=1&vwsrc=0)

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g-clef
...in mice.

~~~
pazimzadeh
With a human study underway.

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rossenberg79
I stopped doing fasts because even though I did notice a boost to my
productivity, most of it was due to not having to stop in the middle of the
day to eat or waste time thinking about eating. In terms of cognitive
benefits, going for a run for 30 minutes in the morning still seemed far
superior.

~~~
bluedino
>> going for a run for 30 minutes in the morning still seemed far superior

Why not both?

~~~
Goronmon
Fasting combined with exercise sounds like a recipe for overeating after the
fact.

~~~
mcfunk
Once the body gets habituated to using fat stores for energy rather than
glucose or glycogen, there's no particular need or urge to eat after exercise.

~~~
rossenberg79
What if you are low on fat stores?

~~~
phonypc
Define low.

Unless you're a competitive body builder on show day, you've probably got
enough fat to cover a few weeks worth of energy needs.

~~~
rossenberg79
12% is not that low, but hardly weeks worth of energy needs.

~~~
phonypc
12% fat on a 150 pound person is good for about 63000 kcal. 31 days at 2000
kcal per day.

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tw1010
What doesn't affect the brain?

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agumonkey
I found that skipping hunger (not real nutritional needs, the need to satisfy
a moment through eating) made me a little hyperactive and in a way if I divert
this slightly manic like rush, I can do things in deep, not in flow but
almost.

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eden_hazard
Anecdotal evidence but this is my third day of fasting and my productivity is
significantly higher. Oddly enough, the hunger I feel is similar to what I'd
feel if I skipped breakfast going into lunch.

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sepisoad
yes fasting can have benefits, but the way most Muslims do it (in summer
specifically) actually hurts. your body needs a minimum amount of water and
salt to work properly throughout the day.

~~~
x1ph0z
Wouldn't that be mitigated by having enough water before he fast begins? I
usually gorge water before and after my fasting for the day.

~~~
neuralzen
I would think that depends. In Indonesia a lot of people do just that and seem
ok (though lots of hacking and coughing), and in Jordan I saw construction
workers toiling in the sun all day who wouldn't drink water while fasting,
which seemed dangerous to me. The Bedouins I met in Wadi Rum were more lax,
saying while traveling or working, they are allowed to eat and drink even
during Ramadan, as a matter of a practicality...being in the desert and all.

