Why does calorie restriction reduce the rate of aging?

[Will Dye]

>>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
>doesn't.  

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.

--Will