Very-low-carbohydrate diets and preservation of muscle mass



R

Roger Zoul

Guest
Hot off the press! This is good stuff....

http://www.nutritionandmetabolism.com/content/pdf/1743-7075-3-9.pdf

Background
I would like to compliment Noakes et al. on their well-controlled study
comparing effects
of different diets on body composition and cardiovascular risk [1]. The
authors suggested
that a very-low-carbohydrate diet (VLCARB) may not be associated with
protein-sparing,
because their dual-energy X-ray absorptiometry (DEXA) data indicated that
both VLCARB
and very-low-fat diet resulted in significantly more loss of lean mass than
the highunsaturated
fat diet. It should be noted, however, that DEXA provides a measure of lean
soft tissue (LST), and the original notion that LST hydration is constant is
not correct.
Rather, LST hydration varies as a function of extra- and intracellular water
distribution
[16]. I feel it is very unlikely that the VLCARB group catabolized more
muscle protein than
the high-unsatured fat diet group. This commentary provides some basic
information on
metabolic adaptations that lead to sparing of muscle protein during a
VLCARB, and
reviews studies examining the effects of VLCARB interventions on body
composition.
 
x-no-archive: yes

Thanks, Roger, excellent reference.

Susan

Roger Zoul wrote:
> Hot off the press! This is good stuff....
>
> http://www.nutritionandmetabolism.com/content/pdf/1743-7075-3-9.pdf
>
> Background
> I would like to compliment Noakes et al. on their well-controlled study
> comparing effects
> of different diets on body composition and cardiovascular risk [1]. The
> authors suggested
> that a very-low-carbohydrate diet (VLCARB) may not be associated with
> protein-sparing,
> because their dual-energy X-ray absorptiometry (DEXA) data indicated that
> both VLCARB
> and very-low-fat diet resulted in significantly more loss of lean mass than
> the highunsaturated
> fat diet. It should be noted, however, that DEXA provides a measure of lean
> soft tissue (LST), and the original notion that LST hydration is constant is
> not correct.
> Rather, LST hydration varies as a function of extra- and intracellular water
> distribution
> [16]. I feel it is very unlikely that the VLCARB group catabolized more
> muscle protein than
> the high-unsatured fat diet group. This commentary provides some basic
> information on
> metabolic adaptations that lead to sparing of muscle protein during a
> VLCARB, and
> reviews studies examining the effects of VLCARB interventions on body
> composition.
>
>
 
[email protected] wrote:
>
> so what does this mean in english??

Some stuff that I got out of it:

1) Since they used the the acronym VLC they didn't test normal
carb intakes for people following most LC plans. They appear
to have used 20 or less so they are only testing Atkins Induction
extension. The advantage is doing so is easy. The disadvantage
is it says little about what is done by very many LCers and what
is recommended by every single popular LC book.

2) The fat loss on very low carb was about the same as the
weight loss on very low fat when given the exact same total
calories. Not encouraging to folks who want LC to work faster
then LF, but the question becomes how low in fat did they have
to go?

3) No mention whatsoever of relative hunger reported by the
subjects. Sometimes what's left out is interesting.

4) They discuss differing water loss levels. Ah, so that's how
LC beats LF. Better early water loss on low carb, no surprise
there.

5) They discuss methods for estimating lost lean using chemistry.
So at least they are noticing that water loss differences occur,
that fat loss happens on either low fat or low carb, and that
both make it harder to measure lean loss.

So it looks to me like their initial goal was to prove that LC
causes more lean loss than LF, but the hard data failed to
justify their iniial goal. As a result they used strange wording
to hedge their bets.

When studies fail to give the desired outcome that's what they
read like. "Weasel words"
 
[email protected] wrote:
:: so what does this mean in english??

From the paper:

"Conclusion
Although more long-term studies are needed before a firm conclusion can be
drawn, it
appears, from most literature studied, that a VLCARB is, if anything,
protective against
muscle protein catabolism during energy restriction, provided that it
contains adequate
amounts of protein."

Hence, if you get sufficient protein, you won't lose lots of muscle while
losing weight on LC. Weight lifting will tend to help minimize muscle loss,
too.
 
x-no-archive: yes

Roger Zoul wrote:
> [email protected] wrote:
> :: so what does this mean in english??
>
> From the paper:
>
> "Conclusion
> Although more long-term studies are needed before a firm conclusion can be
> drawn, it
> appears, from most literature studied, that a VLCARB is, if anything,
> protective against
> muscle protein catabolism during energy restriction, provided that it
> contains adequate
> amounts of protein."
>
> Hence, if you get sufficient protein, you won't lose lots of muscle while
> losing weight on LC. Weight lifting will tend to help minimize muscle loss,
> too.
>
>
>

8 weeks is too short to really point out the differences in LBM, because
the water whoosh of the LC dieters is counted as LBM loss, if I'm not
mistaken.

Susan
 
Doug Freyburger wrote:
:: [email protected] wrote:
:::
::: so what does this mean in english??
::
:: Some stuff that I got out of it:
::
:: 1) Since they used the the acronym VLC they didn't test normal
:: carb intakes for people following most LC plans. They appear
:: to have used 20 or less so they are only testing Atkins Induction
:: extension. The advantage is doing so is easy. The disadvantage
:: is it says little about what is done by very many LCers and what
:: is recommended by every single popular LC book.

Which "they" are you referring to? Reference [1] in the paper concerning
this post? It's kinda hard to put your comments in context without knowing.
I think you're referring to the paper on "Comparison of isocaloric very low
carb...." which is the topic of another post...

According to my reader, catskills is asking about VLC and muscle loss. I
think you'd agree with the comments made by that author (who disagrees with
a statement made by the authors of the other paper which your comments here
seem to be directed at).

::
:: 2) The fat loss on very low carb was about the same as the
:: weight loss on very low fat when given the exact same total
:: calories. Not encouraging to folks who want LC to work faster
:: then LF, but the question becomes how low in fat did they have
:: to go?
::
:: 3) No mention whatsoever of relative hunger reported by the
:: subjects. Sometimes what's left out is interesting.
::
:: 4) They discuss differing water loss levels. Ah, so that's how
:: LC beats LF. Better early water loss on low carb, no surprise
:: there.
::
:: 5) They discuss methods for estimating lost lean using chemistry.
:: So at least they are noticing that water loss differences occur,
:: that fat loss happens on either low fat or low carb, and that
:: both make it harder to measure lean loss.
::
:: So it looks to me like their initial goal was to prove that LC
:: causes more lean loss than LF, but the hard data failed to
:: justify their iniial goal. As a result they used strange wording
:: to hedge their bets.
::
:: When studies fail to give the desired outcome that's what they
:: read like. "Weasel words"
 
Susan wrote:
:: x-no-archive: yes
::
:: Roger Zoul wrote:
::: [email protected] wrote:
::::: so what does this mean in english??
:::
::: From the paper:
:::
::: "Conclusion
::: Although more long-term studies are needed before a firm conclusion
::: can be drawn, it
::: appears, from most literature studied, that a VLCARB is, if
::: anything, protective against
::: muscle protein catabolism during energy restriction, provided that
::: it contains adequate
::: amounts of protein."
:::
::: Hence, if you get sufficient protein, you won't lose lots of muscle
::: while losing weight on LC. Weight lifting will tend to help
::: minimize muscle loss, too.
:::
:::
:::
::
:: 8 weeks is too short to really point out the differences in LBM,
:: because the water whoosh of the LC dieters is counted as LBM loss,
:: if I'm not mistaken.
::

I agree. However, the author of the reply was basically doing a lit review
and just providing info that weighs against a statement made by authors of
another paper who seemed to think that LC is not protein sparing (hydration
seemed to be an issue with a test they did). So I'm not really sure if the
8 weeks is relevant.
 
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