Low carb and endurance running -- results of my experiment

On Thu, 23 Sep 2004 16:29:22 -0000, Robert Grumbine wrote:

It's a matter first of intensity level of the exercise. If you're
running at a level you could (with due training) maintain for 20+ hours,
you're burning mostly fat -- even if you stop at 20 minutes.

The second point, and it's a minor variation on that fundamental principle,
is that your body uses more glycogen when you first start than later
on, even at constant intensity level. iirc, though, it's a matter
of a few percent or tens of percent difference, rather than the factor of
2+ that the intensity level makes.

There you go. Until the body makes this transition, the primary fuel
sources are muscular then systemic glycogen.

Saying is "Fat burns in a fire of glycogen". Some glycogen is
necessary in order to drive the reaction that takes energy (mostly)
from the fats. After you run out of glycogen, the result is
the US bonk, which is not nearly as fun as the UK bonk. What
your body does then is drag protein in to keep the fat-burning
reaction going. This is highly inefficient (= little energy
production) and just downright unpleasant.

For illustration purposes, we sometimes talk as if only one thing
('carb burning' 'fat burning' 'training VO2max' ...) were going on.
The truth is more like all possible reactions are always going on in
the body.

Yes but there is usually a recordable threshold where the energy pendulum
moves form oxygen independency to oxygen dependency.

You're always burning some of each possible substrate,
it's just that the proportions shift. You're always using each
possible energy-supplying reaction; even for ultramarathoners, some
of the lactic-acid producing reaction is done. But the proportions
shift.

Shift they do.

On Thu, 23 Sep 2004 16:29:22 -0000, Robert Grumbine wrote:

It's a matter first of intensity level of the exercise. If you're
running at a level you could (with due training) maintain for 20+ hours,
you're burning mostly fat -- even if you stop at 20 minutes.

The second point, and it's a minor variation on that fundamental principle,
is that your body uses more glycogen when you first start than later
on, even at constant intensity level. iirc, though, it's a matter
of a few percent or tens of percent difference, rather than the factor of
2+ that the intensity level makes.

There you go. Until the body makes this transition, the primary fuel
sources are muscular then systemic glycogen.

Saying is "Fat burns in a fire of glycogen". Some glycogen is
necessary in order to drive the reaction that takes energy (mostly)
from the fats. After you run out of glycogen, the result is
the US bonk, which is not nearly as fun as the UK bonk. What
your body does then is drag protein in to keep the fat-burning
reaction going. This is highly inefficient (= little energy
production) and just downright unpleasant.

For illustration purposes, we sometimes talk as if only one thing
('carb burning' 'fat burning' 'training VO2max' ...) were going on.
The truth is more like all possible reactions are always going on in
the body.

Yes but there is usually a recordable threshold where the energy pendulum
moves form oxygen independency to oxygen dependency.

You're always burning some of each possible substrate,
it's just that the proportions shift. You're always using each
possible energy-supplying reaction; even for ultramarathoners, some
of the lactic-acid producing reaction is done. But the proportions
shift.

Shift they do.

On Fri, 24 Sep 2004 20:10:17 +0000 (UTC), Donovan Rebbechi wrote:

Save your time unless you can qualify yourself as capable, able and
professionally credentialed to analyze a scientific study and its resultant
publication.

I think he can. You'd look less foolish if you googled up on people
before challenging their credentials.

Tell me what you perceive as his credentials.

On Fri, 24 Sep 2004 20:10:17 +0000 (UTC), Donovan Rebbechi wrote:

Save your time unless you can qualify yourself as capable, able and
professionally credentialed to analyze a scientific study and its resultant
publication.

I think he can. You'd look less foolish if you googled up on people
before challenging their credentials.

Tell me what you perceive as his credentials.

Let's see some references then.
"MU" wrote in message
...
On Thu, 23 Sep 2004 16:21:31 GMT, Tony wrote:

Excuse me, maybe you read some texts that I didn't read,

Dozens probably but texts are not necessarily my best sources for info.

but that doesn't
mean you understood them,

When I don't, I have taken great lengths to have them explained or
summarized.

and you don't explain your points very clearly.

Sorry about that.

Question: if the body always uses muslce glycogen up first, no matter
what
the effort level (I think this is what you said),

The body looks to utilize muscular glycogen and similar chemistries as a
preferential source for human movement especially if that movement, in
time, leads into an oxygen dependent state.....

then why does it even
bother to store muscle glycogen?

Because if it doesn't store it, then how can it call on systemic glycogen
for reserves?

Wouldn't nature tend to select those
individuals whose bodies saved their more explosive fuel (glycogen) for
times when it could help save one's life? As in Fight or Flight!

It's been a while since the days when humans required fight/flight
scenarios as regular occurrences. How much has this human physiology
evolved since the saber tooth tiger days? Beats me. I can't find any
citations from then.

Is a master's degree in exercise science and 7 years of application enough?

Throw in a couple of peer reviewed papers for good measure.


"MU" wrote in message
...


Fat is burned in the absence of other energy dependent chemistries
being
available.

On Thu, 23 Sep 2004 04:29:14 GMT, Sam wrote:

You need to read some studies then. When I get back to work, I will
give
you the citations to several.

Save your time unless you can qualify yourself as capable, able and
professionally credentialed to analyze a scientific study and its
resultant
publication.

One of the effects of endurance training is
to increase the contribution of fatty acid oxidation at a given
intensity.

I have no problem with that.

"MU" wrote in message
...
On Tue, 21 Sep 2004 13:07:12 GMT, Tony wrote:

The body can also be trained to burn fats better by doing extremely long
distance at low intensity.

Tony, you need to get off this idea that this exercise or that exercise
accelerates fat burning.

Fat is burned in the absence of other energy dependent chemistries being
available.

What? Explain. I am a bit unclear on this "energy dependent chemistries"
term. Are you talking substrates? Pardon me, I might just be a bit "old
school".

I am sitting here pretty well glycogen loaded (rest day and about 8 g of CHO
per kg body weight today) and yet I am willing to bet that my RER is about
0.75 or so which means I am using fatty acid oxidation as a primary energy
source all the while there is plenty of glycogen present.

Endurance training does improve one's fatty acid oxidation during exercise.
Training shifts the use toward more fat being used when compared to
pre-training. See a thread I started on low carb/metabolism for two
references.

"MU" wrote in message
...
What exactly do you find so distasteful and invalid about low carb
dieting?
Be specific.

On Sat, 18 Sep 2004 17:56:09 GMT, Doug Freese wrote:

Frankly it's a fad built on half truths to make money. Yes you lose
weight but you can lose weight with any eating regimen that restricts
calories. LC makes much about GI and GL as it's base which is smoke
mirrors. Exercise, eat balanced, avoid simple carbs like candy etc. use
some caloric control and you will lose weight.

I do believe, firmly, that there are some people, not nearly as many as
report, that have an swing in appetite upwards when certain carbs are
introduced. That swing is higher than an equal amount of protein, for
instance.

As to LC as a generally useful diet regimen, if one is actually
experiencing carb driven appetite swings, then, OK, have at it.

Perhaps a person just needs to eat a meal with a little fat, a little
protein and moderate carbs. Add some fiber and many people will not have
this "swing" any longer.



My real annoyance comes from ignoramus(his name, not mine) trying to do
endurance running on a LC diet. It's like trying to add water to your
gas tank of your car to get more miles per tank of gas. Any eating
regimin that the exercising body rejects for insufficient fuel tells me
it is not healthy.

Problem is that there are quite a few marathoners who do very well
training
and running and LCarbing. Unhealthy? Probably not.

Who? Define "do very well".


If your body rejects a lowered carb approach, by all means, carb up. If it
accepts it, why change?

The physiology, the biochemistry, of the human body is extremely complex
and very personal.

"MU" wrote in message
...
What exactly do you find so distasteful and invalid about low carb
dieting?
Be specific.

On Sat, 18 Sep 2004 17:56:09 GMT, Doug Freese wrote:

Frankly it's a fad built on half truths to make money. Yes you lose
weight but you can lose weight with any eating regimen that restricts
calories. LC makes much about GI and GL as it's base which is smoke
mirrors. Exercise, eat balanced, avoid simple carbs like candy etc. use
some caloric control and you will lose weight.

I do believe, firmly, that there are some people, not nearly as many as
report, that have an swing in appetite upwards when certain carbs are
introduced. That swing is higher than an equal amount of protein, for
instance.

As to LC as a generally useful diet regimen, if one is actually
experiencing carb driven appetite swings, then, OK, have at it.

Perhaps a person just needs to eat a meal with a little fat, a little
protein and moderate carbs. Add some fiber and many people will not have
this "swing" any longer.



My real annoyance comes from ignoramus(his name, not mine) trying to do
endurance running on a LC diet. It's like trying to add water to your
gas tank of your car to get more miles per tank of gas. Any eating
regimin that the exercising body rejects for insufficient fuel tells me
it is not healthy.

Problem is that there are quite a few marathoners who do very well
training
and running and LCarbing. Unhealthy? Probably not.

Who? Define "do very well".


If your body rejects a lowered carb approach, by all means, carb up. If it
accepts it, why change?

The physiology, the biochemistry, of the human body is extremely complex
and very personal.

"Tony" wrote in message
news:rU04d.3092$Ec4.2824@trndny04...
MU wrote in message ...
On Tue, 21 Sep 2004 13:07:12 GMT, Tony wrote:

The body can also be trained to burn fats better by doing extremely
long
distance at low intensity.

Tony, you need to get off this idea that this exercise or that exercise
accelerates fat burning.

Fat is burned in the absence of other energy dependent chemistries being
available.

What are "energy dependent chemistries" that's a mouthful. Muscle
glycogen
is preserved by the body when possible, burning fats first. Doing long
periods of training at low intensity will improve the fat burning system
over time. Or is Lance Armstrong wasting his time riding 5-7 hours/day at
HR 110-120 in the off season? There are reasons he has more glycogen left
than other racers at the end of the racing day when its needed.

- Tony


I am confused. The body does not have an order in which substrates are
"burned". A mix of fuels is utilized. Even at low intensities, some
glycogen is being used in addition to the fat. The intensity determines the
mix of fuel. Yes, the long "easy" rides that Lance does plays a role
through increased mitochondria, increased capillary bed density, oxidative
enzyme production increases, etc.

As for his having more glycogen left, that is speculation and probably not
good. Now, how I would love to get muscle biopsies at the end of a stage or
time trial!