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starvation and longer life

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starvation and longer life

Postby danihel » Sat Sep 25, 2010 2:32 pm

I heard that when one keeps himself in a state on the bring of starvation the body enters some state of austerity and the cells start to divide on a lower rate, this slows down aging and in consequence extends life.
My question is: what is the reason for the body ever not to be in this state of austerity, are there any drawbacks?
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Postby JackBean » Sat Sep 25, 2010 2:58 pm

Well, because your (and your cell's and all cell's and all life's) only point is to divide and take as much space for yourself and your progeny, that slowing down would mean be killed.
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Postby kolean » Sat Sep 25, 2010 3:59 pm

I am going to go along with the theory that free radicals are what causes mutations, and thus aging (breaking down of the organic machine). And free radicals are caused by all the metabolic reactions that go on in a cell (mitochondria mostly in my opinion). So if you slow down the metabolilc reactions, and a basal metabolism is established (in which there are no deficiencies), then I think that the consequence would be less mutations caused by the free radicals and less aging.
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Postby danihel » Sat Sep 25, 2010 4:15 pm

JackBean: Thanks for reply but to be honest i didn't exactly get your argument.I would say that cells in the body have the only dedication- to help the organism to survive and reproduce, if they wanted only to reproduce themselves we would be just humongous cancer blobs hugging the earth ;p.
Also i would have thought that longer life is an advantage and evolution would prefer longer living individuals.

kolean: Thanks a lot for explanation, still what is the reason that the metabolism is not slowed down constantly if it makes a healthier individual?
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Re:

Postby JackBean » Sat Sep 25, 2010 10:17 pm

danihel wrote:kolean: Thanks a lot for explanation, still what is the reason that the metabolism is not slowed down constantly if it makes a healthier individual?


Read my post, that was the explanation.

Why we're not cancer blobs and living forever? Well, probably because living in the form we are is probably much more effective (you can reproduce, defende yourself etc. what can cancer do? Nothing). And we do not live forever, because of the aging and need to repair all the stuff, so it's better to make whole new organism.
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Re: starvation and longer life

Postby danihel » Sun Sep 26, 2010 8:08 am

JackBean: Well i just can't believe that the ability to age more slowly and live maybe few decades longer would pose evolutionary disadvantage when all that it takes is for the metabolism to slow down which it already is able to do.
I think there must be some other reason like, that the metabolism is not able to deal with bigger quantities of food, create muscles and store energy for worse times or maybe the nerve cells die on a higher rate, i'm just shooting in the dark here :wink: but thats why i'm asking cause i'd like to know.
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Postby JackBean » Sun Sep 26, 2010 11:07 am

I'm not sure, whether are you worrying about the slow or fast metabolism...
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Re: starvation and longer life

Postby danihel » Sun Sep 26, 2010 2:10 pm

Forget about metabolism. One of the advantages when cells are reproducing more slowly is slower aging, now my question is: What are the disadvantages? Won't i be able to run away from a tiger or what's the catch?
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Postby canalon » Mon Sep 27, 2010 6:07 pm

Just to be short: maximizing the life span of individuals do not improve fitness at the species level. In short if an individual survive a long time after breeding age, without providing a support for the next generations it will not improve its chance to pass its genes to the next generation.
So slower metabolism, living on the edge of starvation (more likely to get sick, hurt and to heal) is probably not a winning strategy. whatever an individual might think about it.
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Postby JackBean » Tue Sep 28, 2010 9:26 am

However, it was shown that in humans the viable grandmas actually improve kid survival
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Postby canalon » Tue Sep 28, 2010 3:06 pm

Sure it can (hence the caveat in my answer). But is that always true? and would that have been true a few millions years ago? does it make a difference if you are living in group where the young are cared by the group rather than by a couple of parents? and much more
In fact my point is that it might be an advantage, but the costs are great and that probably explains why this is has not necessarily evolved very often (or did it? what was the ageing rate in humans 2000 generations ago?).
And it is worth repeating: if increasing the life span, however much one might enjoy it, does not increase the fitness of the individual, it will not be selected for.
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Postby JackBean » Tue Sep 28, 2010 5:41 pm

I think that although the average lifespan was probably shorter, still the people were in post-fertile age earlier so still had that effect
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