Quote:
Originally Posted by teaser
Another thing to look at is what is meant by longevity in these studies. If maximal longevity--we might be looking at winning a sort of longevity lottery, the intervention that increases the maximum lifespan may not increase the average or the median lifespan.
Not every species of mouse experiences an increase in longevity on calorie restriction. Or rather--not every species of mouse experienced an increase in longevity when the particular chow used in the study they were involved in was restricted.
We had an earlier discussion on the topic of protein restriction here.
http://forum.lowcarber.org/showthread.php?t=467837
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I read the discussion, but the impression here is that Rosedale read all the literature about lab animals longevity and inferred that most papers gave evidence to the low proteins=longer lifespan hypothesis.a
Pls note that Rosedale does advocate eating fats instead of carbs. Actually, he describes how an abundance of carbs is also detrimental to longevity.
Apparently though, dietary aminoacids control lifespan more than carbs.
Of course, restricting both proteins and carbs would be the best solution.
Even at this point, I have not a clear idea on how much protein is needed to activate the mTOR pathway (there is also some difference in liver mTOR and muscle mTOR and in mTORC1 and mTORC2).
By pure logic, if an abundance of aminoacids is sensed by mTOR as a condition which leads to growth & reproduction mode, we should define the value for abundance. Also, is there an intermediate range (enough proteins, maybe a little more than needed, but not many more) where mTOR is not activated? Probably so.
Also, if the WHO, 2002 nitrogen balance studies are correct, protein requirement in humans is a random variable with a significant variability. This means that we cannot by a single number determine if the mTOR pathway has been upregulated. Rosedale's value seem to mirror the WHO, 2002 Reccomended values, but 0.8 gr/kg si a 97.5 percentile in the WHO study, so in a significant part of the population that would be a value higher than the basic requirement. Is mTOR going to construe that as '
abundance'?
Again, and I should read more in detail the WHO study, were the requirements calculated on an actual or ideal bodyweight? That would change things increasing the requirements if ideal bodyweight was not considered and a non negligible number of individuals was overweight.
I have this terrible hunch that we should individually determine our protein optimum, and that's not so easy. Should we eat less and less until we loose muscle mass and then estimate our zero-balance value? That would be the threshold for mTOR activation. But how do we measure muscle mass? Should we measure nitrogen in stools and urine until we take the balance to negative just to determine the mTOR optimum? A zero or slighlty positive nitrogen balance would not be probably a signal of abundance.