Hi tcomeau

Did you find my explanation below helpful?
I haven't heard from you about this, so I wonder if my explanation was
satisafactory to you, or whether you still have further questions.



On Fri, 22 Oct 2004 15:57:39 +0800, Dunne E. Dawe
posted:

On 21 Oct 2004 07:36:56 -0700, (tcomeau) posted:

Dunne E. Dawe wrote in message . ..
On 19 Oct 2004 09:59:56 -0700, (tcomeau) posted:

This calorie thing. By what mechanism does the body recognize an
excess of calories and by what mechanism does the body then trigger
fat storage.

Through evolution, energy containing foods are conserved by the body
for later use, and stored as the most energy concentrated molecule,
fat. Excess energy-containing molecules are detected by their presence
when all energy requirements are satisfied.

How are excess energy-containing molecules detected, exactly?

By molecular concentration, and enzymes ready to convert them to
storage molecules. The law of mass action. Elementary chemistry.

What
exactly happens when all energy requirements are satisfied?

The high energy molecules build up in concentration and are then
converted to molecules suitable for storage. These go into lipocytes
when in high enough concentration.

I want to
know the metabolic pathways, the hormonal signals, or whatever precise
biological mechanism that detects the bodies energy status and
responds by triggering fat storage or use.

Concentrations of the molecules concerned. Try a simple biochem text.
The body doesn't "measure" the energy content. It has just evolved to
convert excess high energy molecules into fats and then store them in
lipocytes. The actual energy balance always balances when we calculate
the energies concerned.

You aren't answering the question. You are generalising. I want the
specifics. You don't need to write it all out, just point me to a url
or another reference source that specifically lays it all out in
detail.

I've told you. Any first year biochem text.

Fats are made by various chemical pathways (glucose to fat in the
liver, for instance) and this excess fatty acid is stored in
specialised tissues in various parts of the body.


No ****. What is it about calories that triggers the fat storage?

It's fatty acid concentration that "triggers" fat storage. What do
calories have to do with it? Calories are merely a measure of the
energy contained in the chemical bonds of these molecules. This energy
can be utilised for many of the body's energy reqiuiring activities --
muscular activity and the like.

Conversely, by what specific mechanism does the body
detect a dietary calorie deficit and by what mechanism does it then
trigger fat burning.

Fat is burned every minute of every day by the body. Stored energy is
mobilised whenever there is s need for energy by the body that is not
met by the liver's store, or circulating energetic molecules.


You keep explaining it in very general terms. I want to know the
specifics. How specifically does the body recognize that its energy
requirements are not being met by the liver's store, or circulating
energetic molecules?

Concentrfations. You seem to be having some basic conceptual
difficulties.

By osmosis?

This aids some molecules to pass certain barriers to free diffusion.

By fluke?

No, when the concentration on one side of a chemical reaction is high,
the reaction moves to the other side. You have studied a little basic
chemistry, I hope.

By chaos theory? By ESP?

Yet more lack of understanding? And you have had it explained before?
I'm beginning to wonder about your motives.

By hormonal response?

Hormones will be involved in facilitating some reaction pathways.

By sensory cells?

Yes, these can sometimes permit some chemical transactions to go ahead
(feedback loops). Can't think of any particular examples at the
present time.

By receptor molecules?

Not sure what you mean here.

By broadband antennae? Huh?

Are you trying to be dense? You seem to be succeeding.

What are the specific bio-chemical steps in both processes?

I suggest you consult an elementary biochemical textbook to learn all
about lipogenesis and lipolysis and other energy storing and
mobilising pathways. They are quite straightforward and very well
understood.


Can you point me to one that explains how calories and specific
quantitative caloric intake relate directly to lipogenesis and/or
lipolysis.

I've said several times, any elementary biochem text.
As I've tried to explain, molecular concentrations drive reactions.
The molecular species determines exactly how much energy is contained
within the bonds of that molecule.

And more importantly how exactly is the body bio-chemically
aware of its caloric deficit or excess and how exactly does it
bio-chemically trigger lipogenesis and/or lipolysis.

You seem to have a misconception of just what energy is. Energy is
needed by the body to carry out many of its functions. It all
originally comes from the Sun. Every molecule has a certain energy
associated with its chemical bonds. When you break a bond, an exact
amount of energy is transacted. Similarly when you create a bond. The
body does not "measure" energy, it "measures" molecular
concentrations.

I've read quite a number of elementary biochemical textbooks and quite
a few not so elementary and I've yet to see any clear, concise
explanation of the direct and specific connection between caloric
intake and the triggering of lipogenesis and/or lipolysis.

Perhaps you have missed it because of this confusionn of what energy
is. Get that straight, and I think you might be OK.

By the way, I was looking in the archives, and see that all this has
been fully explained to you at least several times previously.
Why do you keep bringing it up? What are your motives here?


You guys keep giving me the kind of general non-answers that you just
BS'ed your way thru just now.

Or you keep having problems understanding plain English. I've seen
some folks have actually pointed you to specific references for all of
this. I've yet to see a biochem text that does not deal with this
topic. It is basic.

It is obvious that if we accept the caloric theory of weight gain and
loss, then the body has to have a way to recognize a state of either
excess energy or a state of energy deficit.

See above. You have quite a problem there. Get your enegy concept
right and you should be well on the way.

And then the body must
take the excess energy and store it or conversely, when the body is in
an energy deficit state, it must start using up fat.

Stop thinking of energy and think of particular molecules. Then you
can look them up to see how many calories they have available when
converted to something else.

You just repeated
the above using a little bit of scientific terminology.

Yes, you had better get used to some scientific terminology. It makes
understandig so much easier. Try writing down some simple definitions
and refer to them as you go.

That is all
that you have done. That is the only response, to this question, that
I've seen in this ng. I keep asking the question and keep getting the
same non-answers.

As I said. Leave the energy out for now, and just think of molecules.
You can introduce the energy later when you are not so confused.

What I asked for was not just a rote repetition of what must be
obvious vis-a-vis the calorie theory. What I asked for was a detailed
scientific explanation of the bio-chemical processes that does all of
this.

I've told you. basically it is detection of molecular concentration
via simple chemical principles.

The metabolic pathways, the hormonal cascades, cells, molecules,
etc. Not just what the body "must" do vis-a-vis calories, but the
actual facts about what it does, and much more importantly,
*specifically how* it does it.

Far too complex to go into here, but all texts I've seen deal with it
well.

What is the specific bio-chemical mechanism that detects the bodies
energy status at any given time?

Molecular concentration. The body can't actually measure the energy
content of a molecule, it can only do what it is programmed to do with
various molecules. When it "needs" energy, it does things with
particular molecules that just happen to contain a lot of energy.

How does it detect the status,
specifically?

Molecular concentration. Gee, you ask this question a lot. I sense
your frustration.

Once the energy status is determined, how exactly does this specific
bio-chemical energy detection bio-mechanism then specifically trigger
lipogenesis and/or lipolysis.

See above.

The questions are so simple and fundamental, yet they have yet to be
answered.

No, the answers given have yet to be understtood by you, I'm afraid