It seems that the natural, instinctive behavior is not always more
efficient than science, since we are by definition "artificial". What was
relevant for survival in the jungle is not anymore in the 20th century.
Some practices that are recommended are not part of our instinctive
behavior: fasting, skipping breakfast, testing cassia every morning,
calorie restriction (CR).

One argument is that no animal has been intoxicated by 20, 30 or 40
years of cooked nutrition, so humans need more detoxing. But that kind of
argument doesn't satisfy me: if some long-term instinctos still feel so
intoxicated that they still need cassia, what do they eat instinctively
for? Maybe a certain degree of toxemia is natural; after all, we are
not immortals.

On the other hand, maybe the selection process sacrified a bit of the
"toxemia" aspect to other ones: muscularity, energy reserves, stocks
of glucose to escape predators (or to hunt), thermoregulation (even to
chimps' standards, some nights are not so warm in Gombe).

Thus, it may be important to determine if some practices like CR, fasting...
are really effective and safe.


Concerning fasting: see for instance Samson Wright's Applied Physiology",
13th ed., Oxford Univ. Press, 1984.

p 460: "The normal non-fasting blood ketone level is small (0.5-2 mg per
100 ml); even a short-term fast (of 2 or 3 days) increases the level as much
as fiftyfold (...). If ketogenesis proceeds at an unduly high rate,
exceeding the rate at which dissimilation cas be carried on by the tissues,
then ketones accumulate in the blood. This condition is called ketosis, and
may lead to the excretion of ketone bodies in the urine"

p 480: [Long fast] "There is (...) a ketosis and ketone bodies appear in the
urine. The usual steps are taken to compensate for the tendency to
adidaemia, i.e., buffering by means of bicarbonate, increased pulmonary
ventilation, and fall of alveolar CO2 tension; increased acidity of the urine;
increased NH4+ excretion (...).
Tissue protein is treated in starvation like food protein and is hydrolyzed
to amina-acids but on a larger scale than normally (...) The released
amino-acids enter the 'common pool' (...) [The pool] preserves the normal
blood sugar without which brain function fails"

> JL:
>
>>BTW, here are further details I read in a book:
>> -urine excretion of H+ considerably decreases the risk of acidosis
>>caused by ketones;
>> -the glucose level is "almost normal".
>>
>>Not very precise and satisfying, eh?
>
> Pat:
>
>No, certainly not, particularly standing alone. Do you find, from the rest
>of the book (whose, and what book please, do you have it handy?), that this
>means that H2O ingestion creates a biochemistry equation in which the H+
>binds with the ketones so that they may detox them by excretion? . I know
>tha ketones are produced in fat catabolism and are found in the urine during
>starvation of an animal. I have forgotten too much, perhaps more than I ever
>knew! What does glucose do in this?Does the open-ended glucose chain combine
>with the ketone and water so that it is rendered a salt, and thus excreted?
>I am certain that this can all be measured quite accurately, which would be
>highly informative; I wonder why the vagueness of the quote? Glucose is also
>present in the urine as a warning of pathology, but I don't understand the
>significance of this to ketosis and fasting: one would think glucose the
>very last thing the body would "want" to get rid of in a fast...

Sorry, I guess I wasn't clear enough. I was referring to the two major
problems in fasting:
 -acidosis due to the ketones,
 -low blood glucose level.
For the first point, I meant that the excretion of H+ (in other words, urine
acidity) reduces the tendency to acidosis. For the second point, the blood
glucose level is about 0.6-0.7 g/l during the first three days (I haven't
got the figures for a long fast), which is lower than the normal 1 g/l but
not extremely low.


Remarks: one should distinguish between a short fast, a long fast and a
low-calorie diet, during which the body's functioing are very different.


Best wishes,

Jean-Louis