On Wed, 19 Jul 2000, Anthony wrote:

> Now I'm confused......  Isn't it pyruvate which increases or speeds up the
> Krebs cycle, which causes an increase in the burning of calories and
> prohibits fat storage???   (assuming one hasn't overdone the calories.)
> It's back to the search engine......  sigh.....  Oliva

Pyruvate is a metabolite in the Krebs cycle, between glucose and
ATP.  I have been able to verify through Medline that pyruvate
and lactate levels are elevated in obese people, and also that
pyruvate interferes with fat utilization.  Whether it also
interferes with fat storage I don't know.

Pennington's theory is that obesity is the body's attempt to
compensate for its impaired ability to use carbohydrates *and*
fats by increasing the fat supply (It's ability to increase the
glucose supply is sharply limited).  So, it's like this:

(1) For unknown reasons, some people have difficulty with the
conversion of pyruvate to ATP, so their ability to burn glucose
is impaired.

(2) This causes pyruvate levels to become elevated.

(3) Although most cells can and do use fatty acids for energy,
elevated pyruvate interferes with this as well.

(4) This causes serum fatty acid levels to rise as well (also
seen in obese people).

(5) This causes the body to compensate (to avoid starvation) by
increasing its fat stores.

In Pennington's own words, "Obesity might be considered as a
compensatory hypertrophy of the adipose tissues, providing for an
increased use of fat by an organism that suffers an impairment
in its ability to oxidize carbohydrates."

Keep in mind that this article is almost 50 years old.  I can't
judge the soundness of his case, but it's interesting in that,
unlike most current low-carb theory, it locates the pathology of
obesity in the utilization,, not the storage, of fat.  It is not
the usual insulin story (Though I don't know what effect insulin
might have on pyruvate use; maybe there is a connection there.).

Todd Moody
[log in to unmask]