
Bacteria in the Intestines May Help Tip the Bathroom Scale, Studies Show - tokenadult
http://www.nytimes.com/2013/03/28/health/studies-focus-on-gut-bacteria-in-weight-loss.html
======
SoftwareMaven
I think this is a great example (well, counter-example) of how screwed up
nutritional research has been. We spent the last 30 years trying to shoe-horn
the low-fat-low-cholesterol-is-everything, when we had _no_ idea how the body
works.

It is great to see research like this happening. I've followed nutrition for a
long time as I've dealt with chronic weight problems, and things have gotten
much more interesting (read: less parroting of the "party line" and more new
research) in the last 5-8 years.

It's unfortunate that so much time was lost, because it takes 10-15 years to
go from mice to people. Now if we could only get some experiments with decent
controls, so we can actually learn something.

~~~
yummyfajitas
It isn't screwed up. In broad strokes, we understand very well. Calories in -
calories out = weight gain. This has been demonstrated in thousands of lab
studies.

That's about 85%. Now we are just figuring out details and special cases.

~~~
raverbashing
Exactly, that's 85%

Someone with a (big enough) caloric deficit _will_ lose weight, sooner or
later

Someone with a (big enough) caloric surplus _will_ gain weight.

Big enough is because the body will adapt its metabolism to small (and one
shot) caloric surpluses/deficits.

But what happens beyond that is very interesting. And so beyond the 'food
pyramid' and "conventional knowledge" it's not funny.

Oh and by the way, protein diets (usually) work. Why? Caloric deficit (of
course) promoted by modified hunger sensation (that's another piece of the
puzzle).

~~~
SoftwareMaven
Losing weight is immaterial. Keeping weight off is what matters, and pretty
much every study for the last 100 years has shown reducing calories does not
keep weight off. Just the opposite: reducing calories invariably leads to a
gain of 5-7%.

~~~
raverbashing
"and pretty much every study for the last 100 years has shown reducing
calories does not keep weight off."

That is possible if it's a small reduction of calories and you're not very far
off your ideal weight.

Otherwise is a thermodynamical impossibility.

And yes, losing weight is one problem, keeping it off is a different matter.

~~~
SoftwareMaven
It is not thermodynamicly impossible because your body is not a fixed system.
It can (and does) regulate energy usage based on how much energy it is
receiving, what kind of energy it is receiving, what the environment is
(primarily reflected through cortisol and stress), etc. all of these
intertwine, making it nearly impossible to look at calories alone to measure,
well, much of anything.

Reducing calories causes the body to reduce its calorie usage and starts
pumping hormones that cause fat to be retained and your desire to eat to
increase, until the hormonal system forces an "override" where you _have_ to
eat more. Sure, there are some people who manage to overcome the hormonal
override, but they are by far the exception and not the rule, and any weight
loss program that tries to override the body's built-in protections against
starvation (which go back who knows how long and exist in pretty much any
animal) is a recipe for failure.

The keys to the whole hormone cycle are insulin and leptin. Any successful
weight loss regimine will have to address those hormones, which calorie
reduction "inflames" rather than "pacifies".

~~~
raverbashing
Yes, you are right (and explained it quite nicely)

But there's an absolute minimum of calories the body need to operate, even at
'low gear' (I'm not sure, but this is around 1000kcal per day), so if you're
really limiting the calories below a certain point you will lose weight.

Apart from that, if you're trying to lose weight, but not actually consuming
less calories, of course you may have a weight gain.

~~~
SoftwareMaven
Fair enough, but I would say that's only useful if you are wanting to lose a
little weight before a cruise or want to get into a lower weight class for a
wrestling match. Weight loss that doesn't "stick" is probably more dangerous
than not losing, because it tends to focus as visceral fat instead of
subcutaneous fat; and, unfortunately, study after study[1] show that dieting
does not result in long-term weight loss[2].

1\. This is a review of 31 studies that comes to the same conclusion:
<http://mann.bol.ucla.edu/files/Diets_don%27t_work.pdf>

2\. My anecdotal story, I tried restricting calories for 15 years with the
result of hitting 350+ pounds. Seven years after a gastric bypass, I've found
low-carb to be the _only_ way I can maintain my weight. Even with the gastric
bypass, I can't limit myself to the 1200 calories or less a day I would need
to maintain (and I feel like crap). Low carb, I never have to even think about
the number of calories (I trade one number for another :) and my energy goes
up.

I was experimenting with this and, when the results were positive, it really
drove me to understand _why_ the results are positive. I'm (slowly) starting
to get an understanding of the biochemistry involved (that is a lay
understanding, for sure!).

------
ChuckMcM
The mouse studies, the C.fid studies, fascinating stuff. Would be a hell of a
project to do flora studies. Perhaps we could blend it with Gate's new toilet
initiative, press this button if you're you willing to enter a survey of gut
flora and a chance to win an Amazon Gift card! Now please don't move while the
swab extends ...

------
draven
I read something similar recently (though the blog post itself is from 2008):
[http://phenomena.nationalgeographic.com/2008/10/06/human-
gut...](http://phenomena.nationalgeographic.com/2008/10/06/human-gut-bacteria-
linked-to-obesity/)

The whole gut bacteria thing is quite fascinating. It evolves depending on our
diet. The intestinal flora of a fetus is boootstrapped with bacteria from his
mother. Gut bacterias can get genes from ingested bacterias:
[http://phenomena.nationalgeographic.com/2010/04/07/gut-
bacte...](http://phenomena.nationalgeographic.com/2010/04/07/gut-bacteria-in-
japanese-people-borrowed-sushi-digesting-genes-from-ocean-bacteria/)

And this kind of symbiosis with bacterias is not limited to humans (the rumen
of cows is filled with bacterias that break down normally undigestible
components of grass such as cellulose.)

I bet research on this symbiosis will produce lots of interesting results!

------
__--__
For as logical a group as I perceive HN to be, any nutrition related article
reminds me of the simple fact that most people can't assimilate new
information when it conflicts with previously held mental models. For whatever
reason, diet is something we get drilled into our head from the time we're
very young. Even though most of it has been thoroughly debunked by scientific
studies (cholesterol, the food pyramid, excessive cardio, saturated fat,
wheat) people refuse to believe it. Every time, I see people trot out the same
arguments (calories in/calories out seems an especially stubborn one).

So, my question is this - How do we communicate new science in a way that will
change people's minds? Or should I just be content that the next generation
might stumble on this stuff through a web search before what they are taught
in school firmly takes hold?

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david_ar
I really don't understand arguments like this - the problem is that some
people have digestive systems that are "too" efficient, and so the "solution"
is to cripple their ability to properly absorb nutrients. It seems rather
wasteful.

~~~
OGinparadise
_It seems rather wasteful._

Honestly who cares? It's not like the food saved will go to feed a starving
kid in Africa or something. Food is rotting in warehouses already, so it' more
of a logistics /distribution thing. That takes time to solve and is a totally
separate issue from the medical one..of people dying and suffering from fat
/obesity. Different groups can work on separate issues.

~~~
king_jester
> That takes time to solve and is a totally separate issue from the medical
> one..of people dying and suffering from fat /obesity.

AFAIK, studies about deaths correlated or caused by being fat have been
totally debunked and had nothing to do with body weight in the first place. To
that end, one does not die from being fat and being fat doesn't mean you are
suffering (except for how people and society treats you as a fat person).

~~~
jwoah12
Sources?

------
jcampbell1
Mouse studies always turn out to be a tease when it comes to weightloss. I say
we skip all the probiotic piddling and go straight for human fecal
transplants.

Unfortunately, it is hard to get researchers and patients to agree to get an
enema of someone else's poo.

~~~
gojomo
It's not that hard when patients are suffering and the treatment works. Fecal
transplants are already being done for other disorders, and patients are
demanding it:

[http://www.nytimes.com/2013/01/17/health/disgusting-maybe-
bu...](http://www.nytimes.com/2013/01/17/health/disgusting-maybe-but-
treatment-works-study-finds.html)

------
jacques_chester
Before people get too excited, remember, correlation isn't causality (aside: I
never thought I'd get to be _that guy_ on HN who says that).

It's just as possible that different microbial populations follow from
obesity.

Actually, it seems more likely that this is the case, given that the
populations change after band surgery.

And, as always, there is no biological mechanism so far discovered that
transcends the conservation of energy and matter.

Given how hilariously silly any thread on diet becomes on HN (because for some
reason saying "net caloric balance is the sole predictor of long term average
body mass" drives people _nuts_ ), I believe I will sit this out to avoid
getting a severe case of XKCD386.

~~~
cromulent
I'll bite.

Net caloric balance is an important predictor, but not the sole predictor.
That's why it "drives people nuts" - because it is not true.

For example:

[http://www.newscientist.com/article/dn23127-abnormal-gut-
bac...](http://www.newscientist.com/article/dn23127-abnormal-gut-bacteria-
linked-to-severe-malnutrition.html)

------
sambeau
Does this suggest that maybe we should be sharing each other's poo to prevent
our gut being dominated by a single bacteria?

And does that suggest, maybe, that obesity is in some way partly caused by
modern hygiene and hand-washing preventing this from happening 'naturally'?

It seems ironic that, after decades of bleach and bacterial hand-wash, I might
be 'cured' of my obesity by eating a capsule someone else's fecal matter.

~~~
adaml_623
The one situation where a suppository is the preferred alternative?

------
brianbreslin
Could we see a legit probiotic capsule that is sold over the counter that has
fat burning capabilities? so we identify the bacteria common in thin people
and let fat people spend $$$ to acquire it?

~~~
gojomo
I'd guess that the balance of bacteria depends more on whole-system factors,
especially diet and personal chemistry/digestive-tract-structure. Unless a
strain is completely missing, adding a few more of one kind might be unlikely
alone to change the equilibrium.

Now, if you knocked out the old strains with antiobiotics, the repopulation
might be more sensitive to the small amounts first reintroduced. These studies
of a wasting disease in Africe offer more hints of the interplay of gut
microbiome, diet, and antibiotics:

[http://www.nytimes.com/2013/01/31/health/antibiotics-can-
sav...](http://www.nytimes.com/2013/01/31/health/antibiotics-can-save-lives-
of-severely-malnourished-children-studies-find.html)

------
shin_lao
What happened to eating _less_?

~~~
epo
Sshh, don't be insensitive, some people have a rare metabolic disorder.

~~~
shin_lao
Sure. That's why one third of the USA is overweight. Probably a rare metabolic
disorder. ;)

------
crusso
Freakanomics had a good podcast on the subject of the healthful role of
bacteria in the intestines. They covered the transplant of fecal matter.

[http://www.freakonomics.com/2011/03/04/freakonomics-radio-
th...](http://www.freakonomics.com/2011/03/04/freakonomics-radio-the-power-of-
poop/)

Memorably, they called a fecal transplant a "transpoosion".

------
ry0ohki
They say this explains why gastric bypass works, but from what I've seen,
people who get gastric bypass can only physically eat a few calories per day
in the beginning without terrible consequences. Eventually you can eat more,
and I've seen the weight go back, so I'm confused why it would be bacteria.

~~~
pygy_
They say it probably accounts for 20% of the weight loss.

Outline of the experiment:

Take a mouse model of human obesity. Divide your sample in three groups:

    
    
        * Gastric bypass
        * Sham surgery (fake bypass, the surgical equivalent of a placebo)
        * Sham surgery + caloric restriction.
    

Observe gut flora change in the first group only.

"Graft" some of the gut bacteria of the three groups in obese mice who didn't
undergo surgery.

Observe a moderate weight loss, only in the mice who received a stool sample
of the first group.

Here's the abstract:

    
    
        Roux-en-Y gastric bypass (RYGB) results in rapid weight loss, 
        reduced adiposity, and improved glucose metabolism. These effects 
        are not simply attributable to decreased caloric intake or absorption, 
        but the mechanisms linking rearrangement of the gastrointestinal tract
        to these metabolic outcomes are largely unknown. Studies in humans and
        rats have shown that RYGB restructures the gut microbiota, prompting the 
        hypothesis that some of the effects of RYGB are caused by altered host-microbial
        interactions. To test this hypothesis, we used a mouse model of RYGB that
        recapitulates many of the metabolic outcomes in humans. 16S ribosomal RNA
        gene sequencing of murine fecal samples collected after RYGB surgery, sham
        surgery, or sham surgery coupled to caloric restriction revealed that
        alterations to the gut microbiota after RYGB are conserved among humans, rats,
        and mice, resulting in a rapid and sustained increase in the relative abundance
        of Gammaproteobacteria (Escherichia) and Verrucomicrobia (Akkermansia). These
        changes were independent of weight change and caloric restriction, were
        detectable throughout the length of the gastrointestinal tract, and were most
        evident in the distal gut, downstream of the surgical manipulation site.
        Transfer of the gut microbiota from RYGB-treated mice to nonoperated, germ-free
        mice resulted in weight loss and decreased fat mass in the recipient animals
        relative to recipients of microbiota induced by sham surgery, potentially due
        to altered microbial production of short-chain fatty acids. These findings
        provide the first empirical support for the claim that changes in the gut
        microbiota contribute to reduced host weight and adiposity after RYGB surgery. 
    

<http://stm.sciencemag.org/content/5/178/178ra41>

