
Self-Control Relies on Glucose as a Limited Energy Source (2007) - Goosee
http://fermatslibrary.com/s/self-control-relies-on-glucose-as-a-limited-energy-source-willpower-is-more-than-a-metaphor
======
wastra
I'm a physician. There are a lot of problems with the original article.

The body is excellent at maintaining glucose concentration in the blood with
food or with days of fasting. Glucose is the primary short-term energy source
for most cells. The brain's energy requirements vary very little with
"thinking" despite the assertions to the contrary in the introduction of this
article. PET works by noting the slight transient increases in some brain
regions with active thought, but moments later (as that 20% of blood flow goes
swishing through the brain) more glucose is available. Meanwhile you are
digesting sugars and carbohydrates, and your liver is supplying most of your
fresh glucose if you are a fasting adult.

Already, before reading the article, I have a low pre-test probability of
their hypothesis being true, so they need extraordinarily strong evidence to
make their point. Instead, there is a very weak chain of experiments, poorly
reported, with borderline statistical significance. Poor charts, no tabulated
results, just terrible.

The primary problem is that they assert that glucose fluctuations occur due to
the exercise of willpower. They try and fail to show this with their first
experiment. However, their "results and discussion" combined section shows
that their control group before and after glucose were very close to their
post-intervention group glucose. p327 para 1.

This shows how weak their statistics and data are, and from this point, you
can throw the whole study in the trash.

~~~
kobeya
Why is it that glucose levels correlate significantly with self reported
“energy” and mood levels?

~~~
wastra
This is one of the earliest tricks of the paper. In the initial discussion
they cite numerous authors on why low glucose, i.e. hypoglycemia, affects
cognition. I have seen many hypoglycemic diabetics in bad trouble from this.
However, the author then silently moves on to asserting that lower levels
within the normal glucose range also have this effect, but without any
supporting evidence.

In addition, the commonly stated myth that people "feel hypoglycemic" could be
easily disproved in 99% of people if it was worth the time and effort to do
so. The awareness of hunger, awareness of time since last meal, and the nocebo
suggestion that such a thing as hypoglycemia in (most) normal people exists.
It is a real thing with some medical problems, and a very few otherwise
healthy people, but far overstated.

If we're into anecdotal levels of evidence, I eat once a day, and _feel_ the
least energetic after eating, for 30-60 minutes.

~~~
kobeya
We’ll sure, food coma is a thing. But at least my own anecdote is that sipping
a sugary drink helps my focus and attention last longer. I haven’t done a
formal double blind study but it is something I noticed after the fact—coffee
doesn’t really work for me, but a sugary, milky coffe does. I found this by
doing regression on a spreadsheet of my intake for a few months and self
reported energy and focus levels.

It was after he fact that I found out this a commonly reported correlation. I
wouldn’t be so quick to discount it as placebo.

------
hyperpape
Important to note that there's a lot of literature surrounding ego depletion,
but it's been called into question for whether it can be replicated:

[http://www.slate.com/articles/health_and_science/cover_story...](http://www.slate.com/articles/health_and_science/cover_story/2016/03/ego_depletion_an_influential_theory_in_psychology_may_have_just_been_debunked.html)

[https://en.wikipedia.org/wiki/Ego_depletion#Reproducibility_...](https://en.wikipedia.org/wiki/Ego_depletion#Reproducibility_controversy_and_conflicting_meta_analyses)

~~~
lkesteloot
Right. Also more notes and links here:
[http://slatestarcodex.com/2015/03/12/book-review-
willpower/](http://slatestarcodex.com/2015/03/12/book-review-willpower/)

------
Goosee
One of the reasons I posted this is because I wanted more discussion on the
topic of this paper. On the website, I didn't see much of a discussion
happening. As in the comments here, it seems that the term coined for this is
"ego depletion".

Recently I've noticed many articles on HN how sugar, carbohydrates, dieting,
etc. affects the brain, gut, and overall human body. Ego depletion is now on
my list of topics to research further because I want to know more about the
human body. I always thought of my Kinesiology class in university to be
important because it taught about the relationship between the health of the
human body and its environment. I hope there will be more findings in the
future so we can, in a sense, optimize ourselves. For example, based on this
paper it seems that eating a snack when studying can lead to better processing
information and staying focused.

~~~
JumpCrisscross
The title threw a flag in my mind because ego depletion is a recently-debunked
hypothesis [1].

[1]
[http://www.slate.com/articles/health_and_science/cover_story...](http://www.slate.com/articles/health_and_science/cover_story/2016/03/ego_depletion_an_influential_theory_in_psychology_may_have_just_been_debunked.html)

------
goodroot
An HN recommended book The Ancient Art of Stoic Joy by William B. Irvine comes
to mind when reading this. Here's a neat quote:

 _We should use our reasoning ability to overcome negative emotions. We should
also use our reasoning ability to master our desires, to the extent that it is
possible to do so. In particular, we should use reason to convince ourselves
that things such as fame and fortune aren’t worth having—not, at any rate, if
what we seek is tranquility—and therefore aren’t worth pursuing. Likewise, we
should use our reasoning ability to convince ourselves that even though
certain activities are pleasurable, engaging in those activities will disrupt
our tranquility, and the tranquility lost will outweigh the pleasure gained._

The idea of practicing will-power, learning to decline known-pleasurable
outcomes as a form of practice, is a well tested idea in stoic philosophy. The
practice seems to suggest that there is an energetic ebb and flow of
indulgence that can be countered by refining one's ability to reason.

------
kazinator
Can someone point out where in the paper they address the objection that a
declining level of glucose doesn't necessarily indicate glucose was "used up"?
Maybe some endocrinological mechanism (like insulin) simply triggered the
uptake of glucose into various cells somewhere in the body.

People cannot be in an excited state, like suppressed arousal of various
kinds, without the _body_ being involved.

~~~
wastra
This and many other points are left unaddressed by the authors. They fall at
the first hurdle, so I hope this discussion can move on to some of the other
interesting things people have mentioned.

------
bayesian_horse
This would mean meditation should lower glucose levels, which it doesn't.
Meditation (or other self-control disciplines) doesn't help with hyperglycemia
in diabetes, either.

It would also mean that during a week-long fast self control should be almost
impossible. Which it isn't, or it wouldn't last for a week or two.

I'm sceptical.

~~~
gcoda
Liver can manufacture glucose to negate some of points you make. But i am
skeptical too, this might be withdrawal symptoms.

Since i started no sugar, no carbs diet my self control improved a lot, but
that maybe self-deception

~~~
bayesian_horse
It may be practice.

------
lotyrin
Glucose depending on performance of a task seems pretty obvious as does
performance of a task being dependent on glucose levels; is there any reason
to believe that the tasks being rooted in self-control has any bearing on the
results here? I would expect to see similar results with any mental tasks, and
these self-control related tasks are seemingly chosen only to make for an
attractive headline (taking advantage of controversy around ego depletion and
the layperson's interest in matters of ego in general).

------
mtw
This is simplistic. When I am on a low carb diet but for whatever reason
decide to eat a doughnut or anything loaded with simple sugars, then I begin
to be irritable, have cravings and generally less focused on work. The
findings applies only for people who are stuck on high-carb diet

~~~
zzalpha
Your reading is simplistic.

This is talking about blood glucose levels, which is influenced by many
factors, including glucose production in the liver.

~~~
leovonl
His reading is simplistic, but so is the article: there is no mention about
different metabolic states, for instance.

The brain depends on a very small quantity of glucose to function - it
arguably is more efficient with ketone bodies, for instance [1] - so covering
not only glycolysis seems like an incomplete research.

[1] [https://blogs.scientificamerican.com/mind-guest-blog/the-
fat...](https://blogs.scientificamerican.com/mind-guest-blog/the-fat-fueled-
brain-unnatural-or-advantageous/)

~~~
wastra
Yes, this is another flaw, but there are much bigger flaws in their work!

Also, they only fasted people for 3h. I've sucked a lot of junk out of
peoples' stomachs who have had longer fasts, so this is not even a
glycogenolisis phase: they could easily have been digesting food still. The
participants were students, so maybe some had drunk alcohol, which, like a
ketone is a two-carbon molecule...

------
digitalmaster
I kinda wish that there was a simple way to quickly see if a paper has been
peer reviewed. Findings like these are interesting observations at best until
they've been replicated and controlled by independent parties... Still an
interesting study. :)

~~~
ASpring
I think you're just talking about replication. Peer review is the process
where authors submit a manuscript and receive feedback from reviewers about
the merits of their paper and how to strengthen it.

This was published in the Journal of Personality and Social Psychology, an APA
Journal. You can find their peer review process here (under "The Peer Review
Process"): [http://www.apa.org/pubs/authors/new-author-
guide.aspx](http://www.apa.org/pubs/authors/new-author-guide.aspx)

------
kbutler
This is why, when I eat a piece of chocolate, I then have so much more
willpower to avoid eating the next piece of chocolate.

Oh, wait. That isn't how it works at all...

------
munificent
Have there been follow-up studies on this? An interesting experiment to
conduct would be to give participants a shot of either glucose or saline and
then test their self-control to see if increasing blood glucose increases
performance.

~~~
maneesh
Sure, some studies have been run, though as an earlier commenter noted,
replicability has been called into question.

[http://www.indiana.edu/~abcwest/pmwiki/CAFE/Wang%20-%20Sweet...](http://www.indiana.edu/~abcwest/pmwiki/CAFE/Wang%20-%20Sweet%20future.pdf)

(summary here:
[https://books.google.com/books?id=evc6jaibNd8C&pg=PT52&lpg=P...](https://books.google.com/books?id=evc6jaibNd8C&pg=PT52&lpg=PT52&dq=soda+willpower&source=bl&ots=a8p0KdAysE&sig=WumdW5Zai-
ttcnwxDw37TzcpgHM&hl=en&sa=X&ved=0ahUKEwiR3cSd_onXAhVE04MKHdOHBu0Q6AEIRzAJ#v=onepage&q=soda%20willpower&f=false))

------
efitz
The article should have been titled “low blood sugar puts one in a bad mood”.

~~~
wastra
They could have gone with: "Sloppy scientists delude themselves about unlikely
hypothesis"

People repeating the fiction that "low blood sugar puts one in a bad mood"
puts people in a bad mood when they haven't had sugar in the last twenty
minutes. We evolved in a low sugar world and did just fine: or was everyone
moody from 200,000 years ago until about a century or two ago?

------
surfmike
“initial acts of self-control impaired performance on subsequent self-control
tasks, butconsuming a glucose drink eliminated these impairments.”

So, having a soda will replenish your ability for self control?

------
leovonl
The study doesn't mention this anywhere, but one can assume it considers only
a state of glycolysis. This makes the the title/conclusion a bit misleading.

In case of ketosis [1], the brain mainly relies on ketone bodies for fuel..
I'm curious about how one's brain would perform in such state - judging by
personal experience, the results would be very different.

[1]
[https://en.wikipedia.org/wiki/Ketosis](https://en.wikipedia.org/wiki/Ketosis)

~~~
opportune
What differences in your thinking did you personally notice while in ketosis?

~~~
bonniemuffin
For me, my mental energy and alertness levels are more stable, because I'm
avoiding the blood sugar roller coaster that I get from eating sugar/carbs.

When I eat carbs, most of my day is either "I'm so hungry I can't think", or
"I just ate, food coma", and I'm only alert and maximally productive for the
brief time after the food coma wears off and before I get hungry again. With
keto, hunger and fullness are less distracting feelings that don't impact my
attention as much.

~~~
lhuser123
Where can I read more about that type of diet ?

~~~
jinglebells
Dunno if it helps, there's a lot of discussion over at
[https://www.reddit.com/r/keto/](https://www.reddit.com/r/keto/)

------
jonnycomputer
I'm pretty skeptical of the ego-depletion model; it doesn't seem to explain
anything that a "self-control is aversive" model wouldn't.

~~~
bonniemuffin
I think I'm on board with your "self-control is aversive" model. Practicing
self control just, well, sucks, and makes me not want to do it anymore!

------
titzer
I don't care what your p values are; put some error bars on your graphs. I
wanna see the distribution.

------
throwawaylalala
What if you are in nutritional ketosis?

~~~
zzalpha
I don't understand the question. It's not like a ketogenic diet results in a
lack of blood glucose... which is good, because if it did, it would kill you.

[https://en.wikipedia.org/wiki/Gluconeogenesis](https://en.wikipedia.org/wiki/Gluconeogenesis)

------
capisce
How does this interact with intermittent fasting or low-carb diets?

~~~
zinssmeister
I do both of these things and especially when I am on a low-carb diet I have a
very short fuse. Politeness goes out the window and compromising as well.

~~~
MattRix
How low do you mean when you say low carb? And for how long? Whenever I first
start doing keto I can be irritable, but after getting into ketosis I have
much more self control (way more than when not dieting at all)

~~~
zinssmeister
I do it a month at a time and yeah I eventually get over it but never fully
into the same calm state as with carbs

------
analogmind
"Moreover, despite our manipulations, we do not intend to advocate consuming
large quantities of sugar as an ideal strategy for improving self-control"

------
purplezooey
I wish some people at my workplace would get a healthy dose of ego depletion.
;)

------
mrfusion
Wouldn’t this mean dieting would be impossible?

~~~
otakucode
Dieting is possible... but you should expect to have significantly decreased
self control in all other areas of life at least for as long as active self
control is necessary to refrain from eating poorly.

~~~
vixen99
Is this an attested phenomenon? How does it work?

~~~
otakucode
I was just reasoning from the studies that exerting self control depletes your
ability to exert more self control. In the study most often cited there is
actually an interesting link to this exact phenomenon, though. The
participants were asked to refrain from eating chocolate (although there is no
indication that these people were trying to diet for any reason). Afterward
they were tested on standard decision-making tasks, at which those who had to
resist eating chocolate performed significantly worse than those who didn't.
Then, they were given a glucose drink and their performance returned to
normal. A person dieting would be both exerting self control to resist eating
things and also resisting things that would provide more glucose for the brain
to be using.

However, I seriously doubt this is specific to self control. I would imagine
performing any action that depletes glucose in the brain would have the same
effects. Prioritizing tasks and deciding tasks to delegate are a couple I've
read which are supposed to be very energy-hungry (I've been reading 'Your
Brain At Work' recently and its mentioned in there).

------
pishpash
This is some joke paper right? Look at Figure 1.

~~~
asynchronous13
What do you consider a joke about figure 1? The methodology and results are
described in the text on the same page. How could it be improved?

