The CR Graph ................

[Guest guest]

Hi Guys:

For those either graphically or mathematically motivated, try the

following. In my opinion it is of critical importance to a

discussion of CR:

Get out a sheet of graph paper and label the X-axis 'BMI'. Put a

value of 10 (Yes, 10) on the left edge of the paper, and a value of

30 on the right side. Then label the Y-axis 'Years of life gained or

lost' with a value of minus 80 at the bottom of the page and plus 50

near the top.

Then add the observations for which we already have data. In the

October 2003 issue of the 'ls of Internal Medicine' a dutch study

found that at a BMI of 30, relative to their benchmark (I forget now

what the benchmark was) seven years of life were lost. So our first

data point on the graph is (30,-7). The same study also found that

at a BMI of 25 only three years of life were lost, so the second data

point on our graph is (25,-3). For our third data point I will

speculate that at a BMI of 10 starvation quickly results in death.

So the third observation is (10,-80).

Looking at this graph with the three known data points, there are two

principal issues that are highly relevant to CR. They are: A) At

what value of BMI does the curve peak? What is the number of

years of life gained at the peak in the curve, wherever that is?

Consider the values between a BMI of 18 and 30. If the dutch study

is correct then the slope of the curve is pretty shallow between

between BMI 25 and 30. Indeed, it can easily be calculated that if

the slope of the curve between 18 and 25 is the same as it is between

25 and 30, then the number of years of life to be gained at a BMI =

18, relative to the dutch benchmark, would be just 2.6 years. If, as

Dr. Walford suggests, maximum human lifespan can be extended as much

as 45 years through CR, then in order for the number of years of life

gained at a BMI of 18 to be approximately 45, the slope of this curve

must very suddenly become very steep somewhere below a BMI value of

25. (Perhaps lightly pencil in on the graph what the curve must look

like if it is to achieve a 45 year gain in lifespan at BMI=18. It

must become extremely steep at some point.)

Similarly take a look at the graph at BMI values below 18. In order

for the curve to register an eighty year loss of lifespan, relative

to the benchmark, at the BMI at which starvation rapidly results in

death, it must drop by more than 100 years (from +45 to -80) between

a BMI of 18 and whatever the 'starvation BMI' is. (Perhaps rather

than the BMI of 10 as I earlier speculated, the starvation BMI may be

13, or perhaps 15?). In any event, whatever the precise value of the

starvation BMI, clearly the curve must fall precipitously starting

not far below BMI = 18.

What this is saying is that, if a 45 year potential gain in lifespan

is realistic, then determining the optimal BMI (or what amounts to

the same thing, the optimal daily calorie intake) is critically

important. On EITHER SIDE of the peak value, the lifespan must drop

off precipitously, in order to exhibit the values we know to be true

at BMIs 10, 25 and 30.

From what I read it seems clear that we do not know what the optimal

values are. Indeed, to complicate things further, they probably vary

from individual to individual. As far as I know no studies have been

done in any species to determine the values of years of life gained

at, say, BMIs between 15 and 25 at single BMI unit increments. A

study in mice to determine the shape of this curve as precisely as

possible at the equivalent of human BMIs between 15 and 25 would be

very helpful.

Food for thought. (Yes. Pun intended!)

Rodney.

[Guest guest]

One thing is certain. Quality of life improves enormously. I now take for

granted my state of continual " wellness " (i.e. illness is now a rarity) and

have to force myself at times to remember my twice a year colds, occasional

flu and at least a once a year stomach bug. For those of us not necessarily

interested in living to be 140, but who are interested in living a high

quality life (whatever the length), CRON is proving itself daily with our

good health. That alone is remarkable.

Obviously, any illnesses to which we may be prone due to genetics such as

heart disease or cancer is being delayed til later life - that is adding

years to the lives of many of us.

on 11/15/2003 1:09 PM, Rodney at perspect1111@... wrote:

> From what I read it seems clear that we do not know what the optimal

> values are. Indeed, to complicate things further, they probably vary

> from individual to individual. As far as I know no studies have been

> done in any species to determine the values of years of life gained

> at, say, BMIs between 15 and 25 at single BMI unit increments. A

> study in mice to determine the shape of this curve as precisely as

> possible at the equivalent of human BMIs between 15 and 25 would be

> very helpful.