
How the Brain Uses Glucose to Fuel Self-Control - softdev12
http://online.wsj.com/articles/how-the-brain-uses-glucose-to-fuel-self-control-1417618996
======
ada1981
>> When you increase such “cognitive load” on someone’s frontal cortex, he or
she exhibits less self-control on subsequent tasks—just like muscle that’s
been exercising hard, then balks at having to move you one step more. <<

Everyone cites this as fact when in reality the science behind it is very
shaky.

See this study from Stanford:
[http://news.stanford.edu/news/2013/august/willpower-study-
su...](http://news.stanford.edu/news/2013/august/willpower-study-
sugar-082713.html)

~~~
maerF0x0
A similar misconception is "I need glucose therefore I should eat sugar" .

The most stable way to supply blood glucose is by eating fat. If blood glucose
is high and circulation is low, then exercise maybe in order, more than
additional eating.

~~~
Florin_Andrei
Stable, maybe - but very slow for sure.

Try doing a 100km bike ride on an up/down road circuit, with fat as the main
fuel.

EDIT: lol, downvotes. This is not about your metabolism while you're sitting
on a chair at work, typing on a keyboard. This is about extreme endurance. I
suggest you actually go ahead and try it, before thinking you've formed any
sort of informed opinion on the subject.

~~~
maerF0x0
Several studies have shown that endurance is equal w/ fat as the fuel. You do
have to spend 4 or so weeks adapting though.

Here is a link to a summary, I couldn't find the actual research articles I
was thinking of though.

[http://www.pponline.co.uk/encyc/sports-nutrition-should-
athl...](http://www.pponline.co.uk/encyc/sports-nutrition-should-athletes-use-
fat-or-carbohydrate-as-fuel-631#)

~~~
justsomedood
That's a really interesting article.

It is fair to point out (which the article does as well) that the athletes
were running at 75% of V02 max, which is lower than when racing in cycling. I
ride a lot, and anecdotally I had a cycling teammate that changed his diet to
consist of primarily fats for 6 weeks. The first few weeks his body was
adjusting and his endurance and power dropped dramatically as you would
expect. After 4 weeks, though, he had come back and had a really strong
season.

The way I understand it is that as intensity increases it becomes more
difficult for the body to convert fat for a large source of fuel, and glycogen
becomes the largest contributor to energy. I know the feeling of a "bonk",
when glycogen depletes, is a really strange one and all fuel is coming from
fat at that point and intensity has to drop by quite a bit in order to
continue.

Our bodies are pretty amazing

~~~
Florin_Andrei
> _bonk_

There's only one thing that gets you out of it quickly - and that's a shovel
full of carbs.

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afro88
They should have had a control group that's completely off sugar. Sugar is an
addictive substance and affects your psychology in a similar way to other
addictive substances. You'd see similar results doing this experiment with
smokers and cigarettes instead of sugar for example.

------
s_q_b
This is well known by bars in many locations that pass out free lollipops and
hard candies as closing time approaches. Anecdotally it causes violent
altercations to plummet.

~~~
nutmeg
Perhaps you are also less likely to talk trash with a lollipop in your mouth.
Clever hack.

~~~
Dewie
Pacifier

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pkaler
This is why I drink a "bulletproof" coffee in the morning at about 7am.
Basically, coffee with butter and MCT oil. Then I have a breakfast of poached
eggs and bacon at about 9am.

My brain and focus is just way better running on fat than on glucose.

~~~
mattieuga
> My brain and focus is just way better running on fat than on glucose.

Your body runs on sugar not fat. Fat will be transformed into sugar to be used
as energy in your body. With that said, it won't create a huge spike in your
blood sugar like drinking a soda, and won't cause a giant release of insulin.

~~~
billyum
Fat isn't transformed into sugar, it breaks down into fatty acids which are
metabolized using a different pathway.
[http://en.wikipedia.org/wiki/Fatty_acid_metabolism](http://en.wikipedia.org/wiki/Fatty_acid_metabolism)
[http://en.wikipedia.org/wiki/Fatty_acid_degradation](http://en.wikipedia.org/wiki/Fatty_acid_degradation)

~~~
nmjohn
Sometimes - but they ARE metabolized through the same pathway.

Essentially:

    
    
        Glucose ->[0] pyruvate ->[1] acetyl-coa -> TCA cycle
    

vs

    
    
        Fatty acids ->[2] acetyl-coa -> TCA cycle
    

The TCA is cycle is the actual main energy generating step.

Other times fat absolutely is converted to sugar. It all depends on the
metabolic needs of the body and one building blocks are available, and what
protein "workers" are able to use the ones that are available.

For example, fatty acid synthase converts acetyl coa back to a fatty acid [3].

[0] Glycolysis:
[http://en.wikipedia.org/wiki/Glycolysis](http://en.wikipedia.org/wiki/Glycolysis)

[1] pyruvate dehydrogenase:
[http://en.wikipedia.org/wiki/Pyruvate_dehydrogenase](http://en.wikipedia.org/wiki/Pyruvate_dehydrogenase)

[2] beta oxidation:
[http://en.wikipedia.org/wiki/Beta_oxidation](http://en.wikipedia.org/wiki/Beta_oxidation)

[3]:
[http://en.wikipedia.org/wiki/Fatty_acid_synthase](http://en.wikipedia.org/wiki/Fatty_acid_synthase)

~~~
wavegeek
None of your refs justify your claim that "fat absolutely is converted to
sugar".

~~~
nmjohn
That wasn't my claim, please don't misquote me. What I actually said was
"Other times fat absolutely is converted to sugar." There is a very
significant difference.

~~~
wavegeek
So what are those "other times" and where is the evidence?

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bcheung
It's a little known fact that the brain can also be fueled by ketones by those
following a ketogenic diet. Energy is more constant as the body is burning fat
continuously instead of depending on constant feeding and the associated ups
and downs in blood sugar. Those following a ketogenic diet report improved
concentration and alertness.

Also, anything that overstimulates the reward system (sugar) will result in
weakened willpower.

~~~
IndianAstronaut
How often before that kicks in? I tried keto for a few days and I could not
bear the post lunch slump.

~~~
bcheung
Are you referring to the fatigue from eating too much or not having any
glucose in your blood stream? People who eat keto meals generally don't feel
any food comas. You might be experiencing low blood sugar because the body is
not burning fat as it should though. The only real way to get into ketosis is
to remove carbs. Personally, I find it easier to just bite the bullet and fast
for several days. Trying to ease out of carbs didn't work for me. This is
probably a good resource to get started: [http://www.ketotic.org/2012/05/keto-
adaptation-what-it-is-an...](http://www.ketotic.org/2012/05/keto-adaptation-
what-it-is-and-how-to.html)

~~~
wavegeek
I toughed it out for six weeks and I was definitely in ketosis per ketostix
testing. I felt as bad as I ever have. So it doesn't work for everyone.

------
Adaptive
One of the researchers mentioned in the article, Roy Baumeister, wrote a book
that I enjoyed (entitled "Willpower"). He gave a talk about willpower and
glucose levels which you can see some of here:
[https://www.youtube.com/watch?v=vefDeoXCBbk](https://www.youtube.com/watch?v=vefDeoXCBbk)

It's not a completely pop-science book, more a translation of his research
into an approachable lay-person format. I recommend it.

(edit - link to book: [http://www.amazon.com/Willpower-Rediscovering-Greatest-
Human...](http://www.amazon.com/Willpower-Rediscovering-Greatest-Human-
Strength-ebook/dp/B0052REQCY) )

------
facepalm
"Each evening participants rated the level of any anger they were feeling
toward their spouse."

Depressing that this is a useful measurement, that is, the level of anger is >
0 on most evenings.

~~~
drcomputer
Emotions can do a math kind of thing (additive, subtractive, multiplicative
and such) from our personal histories and day to day, unrelated tasks. Lots of
people project or distort their emotions in various ways, or they rationalize
away emotions using psychological analysis terms like projection / and an
observation of state changes based on input/output. Having it perfectly under
control feels like being a computer sometimes.

I don't like feeling angry. It's weird.

~~~
kaybe
I can count the amount of times I've actually gotten angry on one hand. I
either get sad or irritated instead. Hm. Maybe I'm misinterpreting feelings?

~~~
drcomputer
People learn and create different ways to handle emotions. People experience
differences and similarities in life experience. People resolve and analyze
their histories, present and future evaluations differently, similarly, if at
all. People have different temperaments, or similar. People can track their
data independently to attempt to control their reactions internally to the
external world, but life does things that make handling response not always
controllable.

I can't say anything about your state anymore than I both simultaneously
understand and do not understand my own.

------
gwern
There are pretty serious problems with the glucose theory right now:
[http://lesswrong.com/lw/jan/kurzban_et_al_on_opportunity_cos...](http://lesswrong.com/lw/jan/kurzban_et_al_on_opportunity_cost_models_of/)

------
stared
It is interesting. Though, as far as I know [1] glucose consumption varies
only a little with brain usage. So either this thing is wrong, or nervousness
because of lack of glucose has different mechanism that some lobes being
hungry.

[1] [http://biology.stackexchange.com/questions/839/how-does-
the-...](http://biology.stackexchange.com/questions/839/how-does-the-brains-
energy-consumption-depend-on-mental-activity)

------
slg
Isn't this common knowledge? Snickers has a whole advertising campaign based
on this idea.

~~~
mattieuga
Maybe never actually studied? I mean vitamin water has a whole advertising
campaign about being healthy, but that's clearly nonsense.

------
myth_buster
I've personally noticed that I get more irritated/angry 4-5hrs after my meal.
This is quite evident for me in the morning when I delay my breakfast. Hence I
try to time my meals religiously. Though getting irritated/angry doesn't
affect my "willpower" as I can still keep my emotions in check and prevent
them from ebbing out.

Coming back to the experiment, shouldn't the will power be benchmarked before
testing for effects of glucose? Hypothetically, couldn't I get a study group
of weak-willed people and enforce the WSJ article's premise as well as get a
bunch of monks and refute it?

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laichzeit0
How do get your muscles to look "full" on a keto diet? I'm talking
bodybuilding here. I see almost everyone "carbing up" before a show
specifically because of this. It also means if you want to follow this sort of
diet you'll end up looking flat most of the time unless you leave the keto
state.

Don't really see the point going low carb if you're lifting weights and
calorie counting since you're replacing muscle glycogen all the time, there's
not a lot of excess energy to be stored as fat unless you're eating way above
maintenance.

------
septerr
"Moreover, during a tough self-control task, circulating glucose levels
plummet, consumed by hardworking frontal neurons. And, remarkably, self-
control improves if subjects sip sugary drinks during the task (with control
subjects consuming sugar-free drinks)."

Then is controlling urge to sip sugary drinks a doomed enterprise?

------
rodly
> The largest lesson is that who we are and what we do must always be
> considered in the context of the biology occurring inside us.

This is such a pointless ending sentiment. I realize the irony here too, my
comment is pointless transitively but I don't care.

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dlwj
If the results are saying "Self control when hungry is lowered." then I agree
completely.

------
swamp40
From the Comments: _" Clearly explains why glucose turns into fat for certain
people."_

------
oooccc
it is good to eat honey or fruit fro your sugar, not table sugar, as table
sugar(white death) gets in your blood very quick causing insulin spike, which
is bad and bad only, unless you completely deprived of energy like in long
distance race.

this stupid sensationalist articles designed to glorify consumption of junk
food are just pathetic and should not be on top of hacker news...

~~~
mattieuga
Honey has a very high glycemic index as well. Almost the same as table sugar.

~~~
oooccc
no, honey is fructose and glucose separate.

sugar is sucrose - glucose and fructose in a very high energy bond.

apart that honey has a lot of other stuff(bee saliva, pollen) which make the
SPEED of absorbtion wayyyyyyyyyyyy different

