
Study finds reducing carbs and replacing with fats leads to increased metabolism - jdminhbg
https://www.nytimes.com/2018/11/14/well/eat/how-a-low-carb-diet-might-help-you-maintain-a-healthy-weight.html
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willsun
In case anyone is interested, this thread includes a more specific set of
methodological critiques made by Dr. Kevin Hall at this week's ObesityWeek
conference (unfortunately does not include Dr. Ludwig's rebuttal):
[https://twitter.com/YoniFreedhoff/status/1062760576869371910](https://twitter.com/YoniFreedhoff/status/1062760576869371910)

Hall's research focus is on mathematical metabolism models, so his critique
comes from that angle: it is possible doubly-labeled water measurements of
energy expenditure may behave differently in a lower-carb environment, so the
observed EE difference may not be meaningful. Ludwig actually briefly
addresses this in their published paper, citing a few other studies suggesting
that DLW is accurate and carb intake does not mess with isotopic measurements.

Hard to tell if this is a meaningful advance for the low-carb crowd, or just
an artifact of insufficiently validated methodology.

~~~
koliber
I am interested in what the article did not say, as it may shed some light on
this critique. Specifically, the weight differences between the groups at the
end of the second phase of the study.

The second phase of the study involved breaking the participants into three
groups. They were fed the same number of calories. Each group had several
biomarkers tracked. This included daily calories burned and ghrelin (a
hormone) levels. I understand the critique targets the measurement of calories
burned, via the doubly labeled water measurement of the metabolic date.

What I wonder is what the average weight change was for each of the three
groups after 5 months. If the claim is that the high-fat diet group burned an
average of 250 calories more, then that should be reflected in an additional
weight loss of about 10 pounds (250 calories per day * 5 months * 30 days in a
month / 3700 calories in 1 pound of fat). This would be because all the people
across all groups were fed the same number of calories. If one group used 250
calories more per day, these extra calories had to come from somewhere. They
would have to come from fat stores and muscle tissue inside of the body,
resulting in a weight loss.

If the weight loss for that group correlates with the doubly labeled water
measurement then it gives more credence to the study's results. If it does not
correlate with weight loss, it is suspicious to claim that one group of people
burned 250 more calories than the other over 5 months while eating the same
number of calories but did not lose any weight.

~~~
willsun
Yup - this line of reasoning is also expressed by Dr. Hall, in the slide here
[1]. To answer your question, the study specifically states: "On average, body
weight changed by less than 1 kg during the test phase, with no significant
difference by diet group in either the intention-to-treat (P=0.43) or per
protocol (P=0.19) analysis."

It is interesting that the study authors highlight the higher energy
expenditure as an advantage for weight loss, but do not seem to directly
address that they did not observe this advantage during the 20 week study
period.

[1]
[https://twitter.com/YoniFreedhoff/status/1062762047677571079](https://twitter.com/YoniFreedhoff/status/1062762047677571079)

~~~
gamblor956
Already commented elsewhere, but the researchers noted that the fed the
participants different amounts of food each day as necessary to maintain
weight. They were testing metabolic differences associated with the ratio of
carbohydrates in the diet.

Studies have already shown that weight loss affects metabolic rates.

~~~
willsun
Thanks for clarifying - this is an important point and seems to explain why
there was no noticeable weight loss.

From the paper: "During the test phase, participants’ energy intake was
adjusted periodically to maintain weight loss within 2 kg of the level
achieved before randomization."

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dnhz
> It found that overweight adults who cut carbohydrates from their diets and
> replaced them with fat sharply increased their metabolisms. After five
> months on the diet, their bodies burned roughly 250 calories more per day
> than people who ate a high-carb, low-fat diet

Is it healthy in the long term to increase metabolism like this? Animal
studies strongly suggest that calorie restriction is beneficial to longevity,
and there is anecdotal evidence in humans (e.g. Okinawans). A higher resting
metabolism means more aerobic respiration, which generates reactive oxygen
species, which damages cells. Better to go the hard way and simply eat less.

~~~
chmike
I'm also worried about the increased fat diet that could clog the arteries.

~~~
stefs
simplified: this, again, is a misconception - fat doesn't per se clog the
arteries. LDL (bad) to HDL (good) cholesterol levels do that, which are
influenced by a lot of factors, like smoking, alcohol, certain kinds of fats
and simple carbs (sugar).

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YeGoblynQueenne
>> The trial cost $12 million and was supported largely by a grant from the
Nutrition Science Initiative, _a nonprofit research group co-founded by Gary
Taubes, a science and health journalist and proponent of low-carbohydrate
diets_.

So, a non-profit funded by a gentleman who advocates for low-carbohydrate
diets found that low-carbohydrate diets are good for you.

That just don't sound like an unbiased study.

~~~
matwood
> That just don't sound like an unbiased study.

The study looks well run. Because someone paid for a study does not
automatically make it biased.

Everyone has biases. In the classic sense, attack the argument and not the
debater.

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nonbel
Wow, another study that fails to actually include a low carb diet:

> _" During the test phase, high, moderate, and low carbohydrate diets varied
> in carbohydrate (60%, 40%, and 20% of total energy, respectively)"_

A low carb diet is going to be 100g (~ 400 cal or 20% caloric intake) per day
at the absolute maximum. Really it should be half to a quarter of that and you
will not feel the need to restrict your eating at all. The way it works for
getting to a normal weight is that you feel less hungry if you limit your carb
intake to those levels.

It's amazing how awful this academic nutrition research is, they just make up
their own false definitions about things then draw conclusions about what
people care about.

~~~
goldfeld
"Low-carb" as practiced freely is also dangerous long term, luckily the
scientists know better than to go to unreasoned extremes.

~~~
_up
How is it dangerous if you supplement Minerals?

~~~
barry-cotter
Eat fatty meat including organ meats and you can eat nothing but meat for
years with no ill effects health wise.

[http://www.mendosa.com/stefansson1.htm](http://www.mendosa.com/stefansson1.htm)

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rawoke083600
OMAD + "Keto'like" (dont judge me ! we got terms like REST'like) is magic

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bencollier49
Haaaaang on.

Given an average human consumption of 2250 calories per day, they're telling
us that we could feed ~10% fewer people if we moved to a fat-based diet
globally?

~~~
koliber
Depends where the fats come from. It takes a lot more resources to grow 100
calories of animal than 100 calories of plant. I imagine there is still a
significant difference of resources needed to produce 100 calories of plant-
based fat and 100 calories of animal-based fat.

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scotty79
Doesn't faster metabolism cause you to agd faster?

~~~
goldfeld
Yes, an engine burning through more fuel will deteriorate faster. Carbs are
easy fuel that won't wear out the system as much as having to process fats and
protein for that same energy benefit.

~~~
qnsi
[citation needed]

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ckdarby
Can someone shine some light on why in 2018 this hasn't been studied majorly
up to this point? Is it funding?

~~~
JPKab
Yep. Funding.

The nutritional science community is generally weak on data, because humans
are expensive to study. This has led to prominent scientists cherry picking
bad data and using correlation to back up shitty hypotheses. The Dr. Hall
quoted in the article is a classic example of this. Attacking the study
wherever he can, because it demonstrates how crappy his lifetime of low fat
diet studies actually are.

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dr_
It’s not clear to me how any of this is new. What id like to hear is how
researchers reconcile this concept with what is seen certain other countries,
mostly Asian, where rice is a staple of their diet, and where you don’t see
the levels of obesity we have in the US.

~~~
draven
In my country (France) bread used to be a staple of the diet and there was no
obesity epidemic at the time.

Perhaps it has to do with total food intake. I live in Bangkok at the moment,
rice is a staple food and Thais eat all the time (they remind me of Hobbits).
Portions are small though, so perhaps that's why I don't see a lot of
overweight people.

~~~
mikekchar
This is correct from my perspective as well (I live in Japan). Not just
portion sizes, but total calories in a meal are dramatically smaller. I went
back to the UK a week ago for a visit and I was stunned to see menus with
calories listed that had individual meals (without drinks or desert!) listed
as considerably over 1000 kcal.

Japanese people often have a good breakfast, but then eat maybe 5-700 kcal for
lunch (in the form of a bentou) and maybe the same for dinner. Sometimes you
get a set bentou at work and it often works out to about 1000 kcal -- but
nobody I know who eats those _ever_ eats dinner. They'll have a drink or two
after work with whatever otoshi (side dish imposed on you as a cover charge in
the drinking establishment) and maybe some snacks.

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sridca
Diets are superficial solutions to the problem of gluttony.

~~~
nikolay
Exactly! People overeat and then they try to speed up their metabolism to
counter the effect of gluttony, which is making them sicker and age faster.

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anonu
What this article says is true and has been known for quite some time. (Not
exactly sure why it's so revalatory in the article)

I've also tried it for years as well to lose and keep weight down. But it's
actually not healthy for you. You're better off eating a balanced diet, not
too much of it, and exercising.

~~~
zackbloom
How are you defining 'healthy'?

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boringusername
Not surprising at all. Related article I posted this a couple days ago
[https://news.ycombinator.com/item?id=18437218](https://news.ycombinator.com/item?id=18437218)

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captainbland
Well, that's one argument for the double down burger.

