Why does calorie restriction reduce the rate of aging?

Will Dye willdye at helios.unl.edu
Wed Aug 26 23:42:54 EST 1992

>>it just seems too convenient to grab any of umpteen different 'advantages' 
>>to explain whatever it is we just saw.  If caloric EXCESS led to longer 
>>lifespans, would we not say this is because of evolutionary advantage? 

>When one discusses aging one has to start with some facts (animals fed less
>live longer than those fed more), propose a theory...
>...and then look for biochemical explanations which connect the two.  I
>would do the same thing *if* caloric excess led to longer lifespan but it

Yes, of course.  This is part of the scientific method that has served us 
so well.  My point here is that the economists do the same thing.  They 
observe inflation, propose a theory, then look for economic explanations
which connect the two.  This is great, but I wind up reading very some 
extremely convincing arguments from economists that still can't tell me 
how inflation will go in the future.  Maybe this is less of a problem in 
biology, but in my world, explanations abound but even the best explanatory
theory is a poor predictor.  Since we can't predict well, what good is the 
theory?  I can't tell you which monetary policy will produce the desired 
result if I can't even tell you what the present policy will do.  Without 
a strong predictive model, we're useless.  That's why my mental alarm 
went off when I read the explantion.  

>...  In fact natural selection works against this because
>species which over-reproduce exhaust their food resources leading to
>population crashes and possible extinction.

Here's the sort of thing I'm looking for!  Note that we're introducing 
some data oustide of the original observation that CR reduces aging. 
There is a large web of data, and theories must fit the entire web.
No doubt biologist have observed overopoulation leading to a crash, 
and that can be used to support the CR theory.  Please don't think 
I'm saying you don't look for this evidence.  I'm sure you're doing 
excellent research.  I just wanted to throw out my "where's the 
prediction?" meme for others to see.  Explanations are great, but 
for the model to be useful, it must ultimately face The Crucible:
"What if..?"  Note that economists and psychologists shy from this.

Since I've made my point, I thik we can drop this thread about 
prediction.  I want to re-emphasize that I wasn't accusing anybody 
of poor methodology, I just wanted to share my idea.  The following, 
however, is of more interest...

>If my hypothesis regarding B-oxidation/protein recycling is correct
>then you lose the benefits of CR as soon as you have built up sufficient
>fat reserves to resume the normal metabolism of fatty acids.  There may be
>a routine, e.g. 2 months of CR to lose 10% of your body weight (fat)
>followed by 2 days of pseudo-fasting every 3 weeks which will give
>you the same results as 30-40% restriction of caloric intake but
>we don't know that yet.

I'm willing to test your hypothesis, since I'm setting up a diet 
anyway.  How hard would it be to get useful measurements to test 
your idea?  Other netters out there may also be interested. 

(discussion of vitamins & minerals)
>Of course determining the proper intake is very hard...

How hard?  I have friends on campus that train athletes.  They do 
some pretty precise measurements of body composition.  Again, since 
I'm setting up a diet anyway, I'm willing to play guinea pig.


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