At 07:10 PM 4/5/97 +0200, you wrote:

>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"

And what is the result to the organism of this short  (total?)fast?
>
>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"

Yes, I see. Not a terrific idea, that one.

 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.

What does this do to physical endurance, cognitive ability, and other
biological function, then? (for short, long, or partial fasting)? This is
very interesting, and I should think vital for anyone choosing which ,if
any, fast to perform?

Pat