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contradictory information about nutrition

post #1 of 3
Thread Starter 
I'm trying to learn a lot about nutrition from the ground up. I don't
know if this will help with weight loss/maintenance and general
health; one school of thought is that if we knew more, we'd be
healthier, but of course another school of thought is that we know
what things are bad for us but we eat them anyway, and what we need is
more willpower, not more knowledge

Anyway, it seems like if you go searching for information
beyond the basics of what types of fats there are and what a
calorie measures, there is (to make a point which must be
crashingly obvious to anyone who has studied up on
nutrition) a lot of contradictory information and advice.
Sometimes this comes from different advice sources giving
priority to different goals (one page may explain
convincinly why the Atkins diet tricks your body into
burning up its fat stores; another page might acknowledge
that this is true, but that saturated fats in meat can also
cause an increase in cholesterol levels, which won't be
reflected in weight gain but can have other harmful
effects). And sometimes two sources of information just say
the exact opposite about what happens in a given situation.

This page: http://www.countcarbs.com/advice/LCG_Myth_Realit-
y_Ketosis.htm says 'If your protein intake is adequate, the
body will not cannibalize its own protein - muscle - but
will utilize the protein eaten for what is called, in
metabolic terms, "gluconeogenesis".'
i.e. when your carbs are severely limited, your body uses
dietary protein for glucose *first*, and then *only* if
dietary protein is insufficient, does your body begin
burning its own muscles for glucose.

On the other hand, this page:
http://www.dietitian.com/locarb.html says "The problem is
when you've depleted your stores of glycogen (stored glucose
in muscle and lean tissue) your body turns to burning
muscles or organs (lean muscle tissue) and dietary protein
or fat to provide blood glucose to supply energy needs. When
this happens, your basal metabolic rate drops because you
have less lean muscle tissue burning calories and your body
thinks its starving and cuts back on energy requirements."
In other words, if you don't eat enough carbs to make
glucose, your body starts making glucose from dietary
protein and the body's own muscles *at the same time*.

Unless I read it wrong, it sounds like these can't both be
correct at the same time -- and there are lots of other
examples. Is the contradictory information due to lack of
scientific knowledge about what actually happens, or is it
just because columnists are not reliable?

And sometimes, even if it's clear what an article says, the
underlying logic just begs more questions. For example, the
http://www.countcarbs.com/advice/LCG...ity_Ketosis.h-
tm article says that your body gets energy either from from
glucose or from fat stores, and the idea behind limiting
carbs is to limit the amount of glucose that gets made, so
that your body starts burning fat for energy. But it goes on
to say that since you need glucose for brain function, you
should make sure you eat enough protein to get that glucose.
This begs the question: if you need X amount of glucose per
day (but no more -- so that your body will turn to fat
stores for energy), then what difference does it make
whether you get that from carbohydrates or from protein?

By analogy, if I didn't know anything about computer viruses
and Internet security threats, and you tried to learn how to
protect yourself by reading the information that columnists
have put out there, it would be a huge mess sorting out all
the conflicting advice. Now that I have about an expert-
level understanding of those topics, when I read some
columnists' advice about the subject, I can usually tell how
they might have reached those conclusions, and how with a
sentence change or two the article would be pretty accurate
-- but I can't imagine actually trying to learn from reading
all that contradictory advice. It took learning about how
computers and email worked, from the ground up, before I
could tell which advice out there was valid. Is it the same
for nutrition experts in this group, reading all the columns
out there about diet and nutrition? Would it be better just
to learn about nutrition from the ground up, to get to the
point where you could be proofreading other people's
columns, than to try and learn from the columns themselves?

Oh, and if anyone happens to know the answer to the above
question (when your body runs out of glucose from
carbohydrates, does it make more glucose from dietary
protein first and only burn up your muscles when the dietary
protein runs out, or does it burn up both at the same time),
that would also be useful...

-Bennett
post #2 of 3

Re: contradictory information about nutrition

"Bennett Haselton" <bennett@peacefire.org> píse v diskusním príspevku
news:e614455c.0404112148.7c6343bf@posting.google.com...
> I'm trying to learn a lot about nutrition from the ground
> up. I don't

So do I, just perhaps for several months longer

> Anyway, it seems like if you go searching for information
> beyond the basics of what types of fats there are and what
> a calorie measures, there is (to make a point which must
> be crashingly obvious to anyone who has studied up on
> nutrition) a lot of contradictory information and advice.

Welcome to the world in nutrition "science"

> priority to different goals (one page may explain
> convincinly why the Atkins diet tricks your body into
> burning up its fat stores; another page might acknowledge
> that this is true, but that saturated fats in

BTW, I would finally like if somebody would show me a
biochemic pathway that causes this satfat problem....

That said, there probably are problems associated with
saturated fats, or better to say, with SOME saturated fats,
but if they change cholesterol levels, then it could be only
indirectly.

> the same time -- and there are lots of other examples. Is
> the contradictory information due to lack of scientific
> knowledge about what actually happens, or is it just
> because columnists are not reliable?

I think both.

> for energy. But it goes on to say that since you need
> glucose for brain function, you should make sure you eat
> enough protein to get

Actually, if you eat low-carb for some time, brain
requirements change, it starts to burn ketones instead
of glucose.

Normally you need about 100g of glucose per day for brain,
but after adaptation your requirements will drop to about
30g / day and rest of energy will be obtained from ketone
bodies. BTW, most people (including
me) report improved brain performance when running on
ketones.

> that glucose. This begs the question: if you need X amount
> of glucose per day (but no more -- so that your body will
> turn to fat stores for energy), then what difference does
> it make whether you get that from carbohydrates or from
> protein?

Carbs inhibit glucogenesis. Of course, switching between glucose-
>fat and fat->glucose happens all the time, anyway while glucose-
>fat is started quite fast (it must be, unless BG would go
too high), fat->glucose gets much longer to kick-in and the
problem is that body reacts to low BG with hunger.

> reading all the columns out there about diet and
> nutrition? Would it be better just to learn about
> nutrition from the ground up, to get to the point where
> you could be proofreading other people's columns, than to
> try and learn from the columns themselves?

I think you should start with biochemistry first:

http://www.indstate.edu/thcme/mwking/home.html

Mirek
post #3 of 3

Re: contradictory information about nutrition

"Mirek Fidler" <cxl@volny.cz> wrote in message
news:c5g9un$197dd$1@ID-198693.news.uni-berlin.de...
>
> "Bennett Haselton" <bennett@peacefire.org> píse v
> diskusním príspevku
> news:e614455c.0404112148.7c6343bf@posting.google.com...
> > I'm trying to learn a lot about nutrition from the
> > ground up. I don't
>
SNIP
>
> I think you should start with biochemistry first:
>
> http://www.indstate.edu/thcme/mwking/home.html
>
> Mirek
>
>
****

And so should we all! Mirek, a great site, perhaps more than
a little dangerous for mooshian dogmatists. Hope we do not
hear of sudden heart attacks. Perhaps it should carry a
warning label! Mike V
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