
The carbs-obesity hypothesis - js2
https://www.givewell.org/carbs-obesity-hypothesis
======
InTheArena
To be fair almost all of the research around this is still outstanding as
basically anybody researching this hypothesis before about 2012 was committing
academic suicide and open for vitriolic attack from the AHA and others. I
highly recommend good calorie bad calorie to get a sense for how incredibly
anti-science nutrition was at the time. No one defends the Keynes studies
anymore, and most agree that simple carbohydrates are ground zero for diabetes
and other “diseases of the modern world”. The only debate left is if it’s the
only cause. In my case after looking at the material and doing a n=1
experiment with a ketogenic diet - the first one I actually ever lost weight
with, I am sold that for my personal Metabolism that this is a effective tool.

~~~
old-gregg
I am fatigued from reading about nutrition, everyone claims to be "not an
expert, but spent a year reading studies" and then proceeds to cite studies
that support their claims.

    
    
        * It's all about calories! carbs/fats/protein ratio doesn't matter [1]
        * It's all about carbs! [2]
    

Why don't PhDs themselves write an easy to read book about this? We have to
rely on "translators" like Tim Ferris [3] and others like him [4] who cite
contradicting studies.

    
    
       [1] https://www.ncbi.nlm.nih.gov/pubmed/19246357
       [2] http://www.ajcn.org/cgi/reprint/23/7/948
       [3] https://tim.blog/2008/02/25/the-science-of-fat-loss-why-a-calorie-isnt-always-a-calorie/
       [4] http://physiqonomics.com/fat-loss/

~~~
js2
> Why don't PhDs themselves write an easy to read book about this?

FWIW, the only reason I submitted this link is that it was reviewed by PhD
Stephan Guyenet and incorporated his feedback. What I gather from having read
Guyenet's blog over the years is: it's complicated. I don't think there's a
single answer that applies to everyone. Within my own household, what works
for me doesn't seem to work for my spouse.

------
simonbarker87
Is there a chance that we are over thinking this in the hope for a complex
golden bullet when in reality the problem is simply eating more calories that
we burn.

I lead a very active lifestyle, I lift weights 4-5 times a week with a focus
on progressive overload, I cycle commute and I mountain bike many weekends a
year. When I want to gain weight (as is desirable when lifting) I eat more
calories (aim for about 3,750 a day) and when I want to loose weight (like in
the spring ready for the summer) I eat a lot less, around 2,500 a day. Doing
this fluctuates my weight from my heaviest of 190 lbs to my lightest of 170
lbs.

My wife does the same, our other friends who lift also do the same and when we
eat more we get heavier and when we eat less we get lighter.

What am I missing here? Because outside the body building world it seems
everyone is hunting for a complex answer that from our perspective seems sort
of solved.... unless you want to get silly lean, then it’s a different ball
game.

I’m not being flippant, I am genuinely curious. Eat less calories, mainly
plants, do more exercise and reduce alcohol consumption (it’s got lots of
calories in it).

~~~
westwooded
A friend explained this to me with an analogy.

"If you make more money than you spend, you will have a lot of money!"

That statement is tautological, and obvious. But it doesn't address how to
become rich.

Now let's compare.

"If you eat more calories than you expend, you will gain weight"

Again, this is likely true, but just very very incomplete. It doesn't attempt
to truly get at the why. There are a few hypotheses for why CICO often does
such a poor job at explaining the obesity epidemic. The two pieces I find most
convincing are (1) there is some metabolic advantage based on the types of
foods you eat, and (2) some of the calories out are excreted via waste and not
processed by the body, and therefore, the simple CICO equation isn't complex
enough.

~~~
bumholio
CICO perfectly explains human obesity and has not been scientifically
disproved yet - the body is surprisingly efficient at breaking down various
types of macronutrients and storing them as fat, regardless of them being
"bad" or "good" calories.

What CICO does not explain is why people are so different regarding their
appetites, nor how can we teach ourselves impulse control. This is where
various low-X diets become relevant, and it's how we get these diet holly wars
with people swearing by the one diet that helped them get CI under control,
without turning them into zombies incapable of CO.

(BTW, my weapon of choice is old school: low on fat except essential fats,
balanced on slow release carbs, high on protein)

------
6cd6beb
>for example, I did not try to evaluate arguments about “good carbs” vs. “bad
carbs.”

That turned me off real fast.

>Perhaps particular types of carbs, fats, or proteins — e.g. refined
carbohydrates, or sugars, or something else — are reliably linked to obesity.
But I haven’t investigated any of those hypotheses yet.

That's much better, but implies the rest of the article doesn't address it.
"Carbs" can mean broccoli or pure sugar. The difference between broccoli and
sugar is "Complex Carbs" vs "Simple Carbs". Simple carbs come from things like
sugar, they break down really fast and the foods that contain them tend to be
very "Calorically Dense", or have a shitload of calories by volume.

EG a small blizzard from diary queen has 660 calories(1). That's the same as
4.3lbs of broccoli (2)

You can polish off a small blizzard after a meal. You cannot eat four pounds
of broccoli in one sitting. 660 Calories is also a respectable size for a
meal, given the generic daily recommendation of 2000 calories. Though again
the blizzard's calories are being added onto a meal.

Carbs are not bad. Any kind of diet with a "silver bullet" to eat or avoid is
overly simplistic and probably just preying on the hopeful.

Understanding what macronutrients are and where they come from and what they
do, and eating a fairly restrictive diet is a solid and sustained way to lose
weight.

For what it's worth, I don't think carbohydrates cause obesity. I think widely
available overly sugary garbage food does. I don't know where you live but
you'd be hard pressed to find a plate of steamed vegetables and grilled
chicken downtown. You can get fast food though.

(1) [https://www.dairyqueen.com/us-
en/Company/Nutrition/Treats/](https://www.dairyqueen.com/us-
en/Company/Nutrition/Treats/)

(2) [https://www.myfitnesspal.com/food/calories/broccoli-
raw-4255...](https://www.myfitnesspal.com/food/calories/broccoli-
raw-425578799#)

~~~
kjeetgill
> I think widely available overly sugary garbage food does.

This "overly sugary garbage food" is what most people are referring to when
they say "carbohydrates cause obesity". Even worse, it's not just "garbage
food" but even well prepared food can often contain a surprising amount of
added sugar. Perhaps "cause" is an imprecise term and a better phrasing might
be: The significant increase of sugar and starches in a typical diet seem to
account for the significant increase in obesity in practice.

Also, the Complex/Simple Carbs are somewhat antiquated in diet terminology and
instead use digestible vs undigestible (fiber). Anyone who's done Keto (a "0"
carb diet) counts carbs using "Total Carbs" minus "Fiber".

This means you're avoiding sugars and starches but advocating for more fiber.
Sugars are simple, starches are complex, but fiber is also complex.

As a fatty who has lost lot's of weight, stress ate my way back years later,
and dropping them again: I found cutting carbs to be helpful, BUT(!) my diet
philosophy is this:

THE BEST DIET is about psychology 80% and nutrition 20%. Most of the value
you're going to get by keeping your weekly calories low. You can try
variations of macronutrients, meal timing and frequency, voodoo, etc. but the
best one is the one you stick with, and can stick with long enough to reach
your goals.

 _Maybe_ you'll need to think about essential minerals and nutrients if you're
trying something really really extreme. But with even minimal variety you
should be good.

------
metabagel
I think that exercise has a strong effect on mood, appetite, digestion, and
metabolism. Grazing continuously probably interferes with the migrating motor
complex, so we will tend to do better if we refrain from eating outside of
mealtimes. Refined carbohydrates tend to be addictive due to the quick
increase in blood sugar levels, and tend to make consuming unrefined
carbohydrates seem less appealing. Eating some fat promotes satiety, which may
help reduce over-eating. So, there are a lot of factors in play.

~~~
theothermkn
> So, there are a lot of factors in play.

I forget where I read this, or even the exact figure, but bowel movements for
some subset of indigenous tribes was something like 4 pounds. I remember
thinking they must be getting ridiculous amounts of fiber. I’m not one to
advocate for “paleo” or any other diet based on “what’s natural,” but it does
seem it’s at least possible that our metabolisms and blood chemistry may have
“grown up” with a lot more fiber than we moderns typically get.

Other factors, indeed.

~~~
SketchySeaBeast
I think we need to be careful assuming that having a 4 lbs poop is a good
thing just because we used to do it. The Inuit's diet was nearly entirely from
animal protein and fats, totally bereft of fiber. People can adapt to a lot of
misery, and I wonder if the need to eat that much fiber was due to other
concerns (for instance, not having access to higher energy concentrated food
stuffs). Either way we can't say that just because someone once did it it's
healthy, or a well adapted behaviour.

~~~
theothermkn
I’m not sure how much more circumspect I could have been.

------
yosito
A lot of people tend to focus on the macronutrient factors of weight gain/loss
(carbs, protein, fat). To some degree, I think those have an effect. As do the
total number of calories consumed/burned. But it seems evident, at least
anecdotally, that there are many other environmental factors that signal to
our bodies how much fat to store vs burn, and much food to crave. I spend a
lot of time with long term travelers and an interesting thing I've noticed is
that many men lose weight when they travel long term, while many women gain
weight when they travel. I don't really think that can be explained by how
many carbs they eat. At least, if that's part of it, it's a very small part.

~~~
CPLX
I noticed that I definitely lose weight when I am traveling and on vacation
and I almost certainly eat and drink more. I'm pretty convinced it's because
the regular office working lifestyle is really so sedentary in comparison.
We're just used to it so we don't notice the stark difference.

~~~
pfranz
Most people I know hate traveling for work because the food options presented
are less healthy and opportunities for exercise are more limited so they tend
to gain weight.

I prefer more active vacations opposed to sitting on a beach, but I also love
food when traveling so much so that I find more places to eat than reasonable
meals. So even when being more active I tend to plateau or gain weight. The
worst is traveling to a place where the food isn't good. The one cruise I took
eating felt like a chore. There were too many options to eat, but none of the
food was very impressive.

------
hourislate
>Perhaps particular types of carbs, fats, or proteins — e.g. refined
carbohydrates, or sugars, or something else — are reliably linked to obesity.
But I haven’t investigated any of those hypotheses yet.

It has always been my impression that Gary Taubes et al have always pointed to
sugar and processed foods as the carbs we should avoid.

How could anyone get fat eating broccoli, lettuce and healthy vegetables?

------
stefan_
People want to desperately believe there is some magic bullet food that makes
them thinner, no one wants to change their behavior. The "commute by car"
correlation with obesity, to name just one, is a lot better than the "food X"
one.

~~~
fbonetti
This isn’t a magic bullet. When you eat carbs, your body produces the hormone
insulin in order to convert blood glucose into usable energy. Excessive
insulin production triggers the body to store energy as fat. If you
drastically reduce your carb intake, your body will enter a state of ketosis
where fat will be burned as energy. Barring some rare medical or genetic
issue, this WILL cause you to lose weight. It’s a scientific fact. Just take a
look at type 1 diabetics prior to diagnosis. They’re skinny and frail due to
being unable to produce insulin.

~~~
allover
> Excessive insulin production triggers the body to store energy as fat.

The 'insulin hypothesis'? Completely unproven.

> If you drastically reduce your carb intake, your body will enter a state of
> ketosis where fat will be burned as energy. Barring some rare medical or
> genetic issue, this WILL cause you to lose weight. It’s a scientific fact.

If you reduce your overall calories you'll lose weight, you can do that on any
diet. That's the only thing that is a scientific fact.

~~~
undeadsushi
[https://www.medicalnewstoday.com/articles/253713.php](https://www.medicalnewstoday.com/articles/253713.php)

"The research indicates that people can maintain a healthy weight by
constantly bringing the levels of insulin back to a healthy minimum. This can
be done by increasing the time between meals and eliminating snacks, without
making amends at mealtime."

I believe this is the actual study: [https://www.cell.com/cell-
metabolism/fulltext/S1550-4131(12)...](https://www.cell.com/cell-
metabolism/fulltext/S1550-4131\(12\)00095-2)

~~~
allover
Well your quote certainly does not suggest a proof of the insulin hypothesis.

Does the study control for calorie intake and show that preventing insulin
spikes with the same calorie intakes reduced overall weight gain? Surely if
that was the case they'd just say that?

------
21
Speculating wildly here, would it be possible after a meal to drink a liquid,
which contains chemicals which bound to the carbs and makes them un-
absorbable? Some sort of carb neutralizer?

Basically vomiting your meal out like the romans did, but in a more elegant
way.

~~~
civilian
You'd probably want to drink it beforehand, but maybe! You'd have to make the
chemicals also resistant to being dissolved and absorbed by stomach acids &
the gut.

------
_bxg1
Any "hypothesis" that tries to reduce something as complex as nutrition to a
single factor is going to be easy to shoot holes in. This article sets up
carbs as a straw-man.

Simple carbs are calorie-dense and tend to increase hunger. There are many
more factors at play, but that doesn't invalidate the fact that reducing your
simple-carbs intake will probably help and not hurt your efforts to lose
weight.

------
natural219
As a keto practitioner, the obvious recommendation I'd add for further
research is to distinguish between "low-carb" and "<20 grams of carb per day".
For achieving ketosis, "low carb" is a completely orthogonal diet.

I'm a little sad that he didn't discover this distinction early on in his
findings, since the rest of this is very interesting and well-researched (just
irrelevant to the keto question in particular).

I'd also add that exercise is another important high-level distinction to make
that confounds the rest of the discussion, particularly the analysis of paleo
/ ancestral diets, which presumably had very high levels of exercise compared
to modern sedentarians.

------
DanielBMarkham
After 12 weeks on keto, I have learned something important about diets.

Lonely? Need a friend? Would you like advice? If so, then post on social media
about dieting. Everybody has an opinion and everybody is quite passionate
about them.

Having said that, my gut feeling is that we're going to see a sea change in
nutrition over the next 5-10 years as the older generation dies out and new
ideas take root. I'm seeing some exciting things in the keto community,
including what looks to me like a lot of science and math that has a
tremendous positive impact on folks. And it's not calories in, calories out.
I'm able to do heavy cardio for 90 minutes without soreness. That's never been
true for me.

Exciting times.

ADD: I clicked on the links, but I was unable to determine exactly _what_
hypothesis the author was studying. Looked like just a meta review of a bunch
of macro information, but maybe I missed it.

~~~
SketchySeaBeast
> And it's not calories in, calories out.

Based upon your last statement, I assume you're on keto for weight loss, if so
how has weight loss been, how many calories are you eating now vs before, and
how stringent was your measurement?

~~~
DanielBMarkham
I'm in it for fitness, but I'm out-of-shape because I'm overweight. I have
made it a point not to weigh and instead judge my progress on changing clothes
sizes and aerobic capacity.

I'm down an incredible amount, maybe 6 inches or more on my waist.
Inflammation and joint pain are gone as well. In addition, I don't get tired
as much.

Basically my entire system has changed.

What I'm religious about is logging everything I eat. So I log calories. And
of course, I eat less of them. (I think this is one of the confounding
variables when people look across studies simply at macros). So in a way,
there is some thermodynamics at work, but the thing is: _that 's not the
controlling factor_. Limiting carbs changes my relationship to food. Once
that's done, it doesn't matter so much how much I eat. I could go a day or two
eating nothing. I still have hunger, but it's not an overwhelming feelig that
drives eating too much like it used to be. Nowhere close.

I'll probably weigh in another 12 weeks. I need to weigh sometime.

I'm usually between 1200-1400 calories. I burn about 1300 daily on cardio. I
have been pigging out the last few days, however, with my intake up around
1550 calories or so.

In all honesty, I just don't feel like eating in the same way I used to. My
relationship with food has changed in a profound way that is difficult to
relate to people who haven't been here.

~~~
naasking
Too steep a caloric deficit can be dangerous. For instance, you lose muscle as
well, and part of the muscle loss happens in your heart. Not good to say the
least.

High protein intake can offset this somewhat, but not entirely, so aim for a
500 calorie deficit at most. In fact, you should cycle calorie deficits week
to week, ie. one week in deficit, one week at maintenance. This actually
accelerates fat loss because it prevents metabolic adaptations to lower
caloric intake. See the MATADOR diet:

[https://www.nature.com/articles/ijo2017206](https://www.nature.com/articles/ijo2017206)

~~~
DanielBMarkham
Thank you.

The protein/muscle-mass rule is one of many things the community continues to
argue about, sadly.

I'm eating between 1-1.5g per ideal kg of body weight daily. I also regularly
measure my muscle and fat mass, keeping an eye on things. (Although not with a
high-end machine). It's something I am quite concerned about.

I am also on-guard for hair loss and some of the other signs of my system
switching over to starvation mode. So far none of that has happened.

------
MisterTea
tl;dr - cut out added sugar, and lower complex carb intake from your diet and
be amazed.

Last May (2017) I weighed about 215 lbs/~98 kg (my peak was 235 around 2012).
I really wanted to lose weight and started at the most obvious place: what am
I eating? Well after some basic research and thinking I decided that sugar was
my target so I started reducing added sugar intake. Eliminated juices, soda,
coffee with sugar, sweet and savory foods like bbq sauces, and all the sweet
treats I loved to eat. At this point Ill admit that I had a sweet tooth and
ate a lot of sugary foods and drinks. You'd always catch me with some
chocolates or a box of cookies in the cupboard. No more.

It wasn't exactly easy and it took some time to adjust my eating and whittle
down my added sugar intake to almost nothing. The only sugar came from the
occasional piece of fruit and yes, the rare cheat desert, maybe once every two
weeks. It worked. By November I started to see results and people were
commenting on my weight loss. I continued and this past January I started to
realize my carb cravings were mostly gone. I can eat a breakfast of two eggs
and some oatmeal and not be hungry until well after lunch. Your hunger goes
down because all the carbs arent messing with your brain. BUT! I have to be
careful, my hunger dropped to the point where I realized I was under eating
and losing weight too fast. By march I was starting to look real skinny and a
few people commented that I looked like a: crackhead, heroin addict, cancer
patient, or anorexic. One guy took me aside at a party and asked if I was
undergoing chemo.

Now I weigh 158 lbs or ~73 kg. All that time I did not exercise. Just heavily
adjusted my diet. I also bumped into a personal trainer last month who runs a
free weekly crossfit bootcamp in a local park so I started that. I also used
his advice for performing simple home exercises (screw gyms) and I'm already
seeing results as in muscle definition. I am looking to put some muscle mass
on to push myself back up to 165-170. Don't wanna get swole, just good hearty
core strength. Maybe get back into boxing and judo/jujitsu.

Far as carbs go, they really mess you up. The past three days I ate like shit,
the worst in the past year. Pizza lunch at work, leftover pasta from a
coworker with garlic knots, empanadas, I had a redbull, and some more pizza. I
feel this heavy bloated feeling in my stomach. Ugh. So yea, carbs are bad,
mkay.

My diet? Nothing special but I avoid exceedingly fatty foods like cheese (I
know, I know, the horror) and red meat as well as anything with added sugar,
and excess bread. So mainly chicken, some fish, turkey for protein and I love
green vegetables so lots of broccoli, spinach, brussel sprouts, kale, swiss
chard, asparagus, and bok choy. I usually saute the vegetables in a pan with a
little olive oil and lots of garlic (cant get enough of it) and cook the meat
in the oven. Just keep a cabinet full of spices and you'll never get bored of
eating. And one last thing, remember how said I had a sweet tooth? Well that
went away somewhat and very sweet things that I used to like are now too sweet
and somewhat repulsive and soda gives me a stomach ache. Amazing what a sugar
"cleanse" will do to the body.

~~~
shakestheclown
You ate pizza, pasta, garlic knots, empanadas, redbull and more pizza and
blame carbs for your bloating?

~~~
GW150914
Starch and fat, starch and fat, starch and fat, sugar and carbonation, starch
and fat... Jesus. Cut out a lot of the fat, add some lean protein and a _lot_
of soluble and insoluble fiber and he might feel better. I’m not shocked
though, when I’ve spoken to friends who jumped on the “bad gluten” train I
hear similar stories.

My conclusion though, is whatever gets people to eat a bit less and a bit more
varied diet is worth it. If they have to believe in spurious causality and it
gets them to binge less on garbage, that’s still a win.

~~~
shakestheclown
Yep, exactly. The best diet is the one you will stick to. Everything else is
secondary. If it's low carb or vegan or paleo or mediterranean great. If it's
the Twinkie diet, not as great but whatever. Penn lost a ton of weight on the
potato diet starter phase of his diet.

Personally, I lost 50 lbs through a combination of exercise plus homemade
vegetable/fruit juice replacement of two meals --which would be high carb.
Some people would not be able to deal with that so it wouldn't work for them.

------
hulton
For most people: If Calories In > Calories Out, you're going to gain weight if
you're consistently eating that way for long periods of time. It doesn't
matter where your surplus of calories is coming from necessarily. However, a
surplus of calories coming from carbohydrates is more likely than fat and/or
protein for most people. Having said that, high fat intake + high carb intake
is also common for many people, especially if you eat out.

[http://www.bodyforwife.com/keto-and-low-carb-diets-kill-
perf...](http://www.bodyforwife.com/keto-and-low-carb-diets-kill-performance/)

~~~
InTheArena
Weight is only one factor though. Congestive heart disease and diabetes and
cancer are the real risk, and there is a ton of evidence that simple sugars a
drive the growth of these diseases.

