Re: Re: What is CRON? - 18% more food?

[Guest guest]

>From: " citpeks " <citpeks@...>

>Reply-

>

>Subject: [ ] Re: What is CRON? - 18% more food?

>Date: Thu, 05 Aug 2004 16:15:39 -0000

>

> >>>>

>From: " Dowling " <dowlic@h...>

>Date: Thu Aug 5, 2004 3:15 am

>Subject: RE: What is CRON? - 18% more food?

>Or, rather, that's 'cause it's total calories that count, not

>calories/body

>weight. (Not quite awake, yet )

>====

>From: " Rodney " <perspect1111@y...>

>Date: Thu Aug 5, 2004 7:23 am

>Subject: Re: What is CRON? - 18% more food?

>In CR, an X percent decline in calories usually produces a percentage

>decline in weight greater than X. So, yes, mice (people,

>nematodes, .....) on CR are 'better' fed than those on ad lib,

>especially if they are paying attention to ON.

> >>>>

>

>: If it is only total calories that count, then only

>five-foot short people who require few calories will live long, and

>there is no hope for any 6-footers who have higher caloric

>requirements!

This appears to be the case. From CR Society discussion:

" I think this points out that being short, and therefore having a lower

absolute calorie requirement to start with, gives one a longevity advantage

right out of the gate - a win for the shorties among us. But I think it also

points out that short people may find it more difficult to gain extra years

on top of those they inherit via their practice of CR.

I think it also points out the longevity challenge tall people face. There

is no way in heck you or I are ever going to approach the absolute calorie

numbers of a small person like Walford - even a Walford eating ad

lib. Put another way, larger people like ourselves practicing what we might

consider pretty torturous CR are still unlikely to exceed (or even approach)

the lifespan of a well-nourished short person eating ad lib. Might be

somewhat discouraging for some, particularly since in general people aren't

envious of, or even aware of the modest lifespan advantage short people

have. "

>

>Rodney: You are right. Your statement has been verified experimentally

>many times. Trying to make sense of the situation, I came up with the

>following:

>

>===

>Mice put on a 40% calorie restricted (CR) diet after 9 weeks of age

>have an adult body weight that is 49% less than mice fed ad libitum

>(AL) (http://snipurl.com/4d7w). Considering that CR mice receive 60%

>of the food eaten by AL mice and that CR mice have an adult weight of

>51% of the weight of AL mice, CR mice eat 18% more than AL mice on a

>body weight basis.

>

>How can this information be reconciled with the fact that the degree

>of caloric restriction, within physiological limits, increases maximum

>life span proportionally? Obviously, even if the CR mice are eating

>relatively more food than AL mice, they are not eating as much as they

>need, otherwise there would be no CR longevity effect. How can we

>calculate the caloric deficit?

>

>Let us start by noting that the adult weight for CR mice is

>proportional to the degree of CR when CR is started at 9 weeks. This

>can be expressed as:

>

>CRW9 = ALW * (1 - CR) / (1 + CR/2)

>

>Where CRW9 is the weight of the adult CR mice, ALW is the weight of

>the AL mice, and CR is the caloric restriction (%CR /100). From this

>we would estimate the weight of mice on 40% CR to be half of the AL

>mice:

>

>CRW9 = ALW*(1-0.4)/(1+0.4/2) = ALW*0.6/1.2 = ALW*0.5

>

>The CR/2 term in the expression was chosen to fit the data from

>Mattson. The formula needs to be checked to see if it agrees with

>results obtained by using other degrees of caloric restriction.

>However, for the case when CR is zero, CRW = ALW, which is what we

>would expect.

>

>At this point we need to introduce the term " Metabolic Capacity " (MC)

>which would be the amount of food that can be eaten ad libitum by

>animals of a specific size. AL mice, by definition, eat exactly 100%

>of this amount. If we assume that MC decreases at a smaller rate than

>the body size of the adult animals on CR diets decreases, there will

>always be a caloric deficit for CR mice, in spite of the fact that CR

>mice eat more on a body weight basis. Let us define MC as follows:

>

>MC = (1 - CR) * (1 + CR/2)

>

>For mice on a 40% CR diet, MC = 0.6*1.2 = 0.7

>

>This can be interpreted as meaning that the adult 40% CR mice are

>getting 60% of the food of AL mice, but that ad libitum they might

>consume 70% of the food of AL mice. This would need to be verified by

>an experiment where mice on a 40% CR diet, once having reached

>maturity and their maximum 50% size, would be allowed to eat ad

>libitum, and their consumption monitored. Do these mature, small mice

>eat 70% of the food that AL mice eat? The results would allow

>modifying the CR/2 term, as necessary. Note that if CR is zero, MC =

>1, as it should be.

>

>If these arguments have any validity, the real rate of restriction of

>the 40% CR mice is 14% because of their smaller size (100 * (0.7 -

>0.6)/0.7 = 14%), although the CR mice are eating 18% more than AL mice

>on a body weight basis.

>

>I am hoping that the readers of this forum who have the inclination

>and the time to search the literature can provide data about:

>1) the mature weight of CR mice vs. AL mice for various percentages of

>CR to refine the calculation for CRW for mice started on CR at 9

>weeks, or other stages of life.

>2) provide any information about how much adult mice raised on CR

>diets eat ad libitum to refine the notion of Metabolic Capacity.

>

>CR experiments on mice show that a 40% restriction from adolescence

>results in a stunted body size which requires fewer calories in

>adulthood. From the assumptions about Metabolic Capacity, it seems

>that CR started in adulthood should probably not exceed 14%.

>

>Tony Zamora

>

[Guest guest]

>From: " citpeks " <citpeks@...>

>Reply-

>

>Subject: [ ] Re: What is CRON? - 18% more food?

>Date: Thu, 05 Aug 2004 16:15:39 -0000

>

> >>>>

>From: " Dowling " <dowlic@h...>

>Date: Thu Aug 5, 2004 3:15 am

>Subject: RE: What is CRON? - 18% more food?

>Or, rather, that's 'cause it's total calories that count, not

>calories/body

>weight. (Not quite awake, yet )

>====

>From: " Rodney " <perspect1111@y...>

>Date: Thu Aug 5, 2004 7:23 am

>Subject: Re: What is CRON? - 18% more food?

>In CR, an X percent decline in calories usually produces a percentage

>decline in weight greater than X. So, yes, mice (people,

>nematodes, .....) on CR are 'better' fed than those on ad lib,

>especially if they are paying attention to ON.

> >>>>

>

>: If it is only total calories that count, then only

>five-foot short people who require few calories will live long, and

>there is no hope for any 6-footers who have higher caloric

>requirements!

Right on! From CR Society discussions:

" ...But you are right - it is hard to argue with the data. And I agree the

data

appears to show that it is absolute calorie intake that counts for

determining CR benefits, at least up to a point (speculatively in the

neighborhood of 1000kcal/day for people) beyond which we can't extrapolate

rodent data w/ much confidence.

What I was trying to do is explore the implications of this data, which in a

nutshell appear to be:

a) Short people start out with a longevity advantage, and tall people will

be hard pressed to catch up.

Percent restriction from one's own ad lib intake doesn't matter. In other

words, dropping 500kcal/day is likely to result in a fixed lifespan

extension (on average), regardless of whether you're starting out at

3500kcal/day or 1500kcal/day.

c) Adult onset CR to the degree people practice it is unlikely to result in

more than somewhere in the neighborhood of 8 extra years of life, and

perhaps substantially less if you start out small, and therefore eating

relatively few calories to begin with. "

>

>Rodney: You are right. Your statement has been verified experimentally

>many times. Trying to make sense of the situation, I came up with the

>following:

>

>===

>Mice put on a 40% calorie restricted (CR) diet after 9 weeks of age

>have an adult body weight that is 49% less than mice fed ad libitum

>(AL) (http://snipurl.com/4d7w). Considering that CR mice receive 60%

>of the food eaten by AL mice and that CR mice have an adult weight of

>51% of the weight of AL mice, CR mice eat 18% more than AL mice on a

>body weight basis.

>

>How can this information be reconciled with the fact that the degree

>of caloric restriction, within physiological limits, increases maximum

>life span proportionally? Obviously, even if the CR mice are eating

>relatively more food than AL mice, they are not eating as much as they

>need, otherwise there would be no CR longevity effect. How can we

>calculate the caloric deficit?

>

>Let us start by noting that the adult weight for CR mice is

>proportional to the degree of CR when CR is started at 9 weeks. This

>can be expressed as:

>

>CRW9 = ALW * (1 - CR) / (1 + CR/2)

>

>Where CRW9 is the weight of the adult CR mice, ALW is the weight of

>the AL mice, and CR is the caloric restriction (%CR /100). From this

>we would estimate the weight of mice on 40% CR to be half of the AL

>mice:

>

>CRW9 = ALW*(1-0.4)/(1+0.4/2) = ALW*0.6/1.2 = ALW*0.5

>

>The CR/2 term in the expression was chosen to fit the data from

>Mattson. The formula needs to be checked to see if it agrees with

>results obtained by using other degrees of caloric restriction.

>However, for the case when CR is zero, CRW = ALW, which is what we

>would expect.

>

>At this point we need to introduce the term " Metabolic Capacity " (MC)

>which would be the amount of food that can be eaten ad libitum by

>animals of a specific size. AL mice, by definition, eat exactly 100%

>of this amount. If we assume that MC decreases at a smaller rate than

>the body size of the adult animals on CR diets decreases, there will

>always be a caloric deficit for CR mice, in spite of the fact that CR

>mice eat more on a body weight basis. Let us define MC as follows:

>

>MC = (1 - CR) * (1 + CR/2)

>

>For mice on a 40% CR diet, MC = 0.6*1.2 = 0.7

>

>This can be interpreted as meaning that the adult 40% CR mice are

>getting 60% of the food of AL mice, but that ad libitum they might

>consume 70% of the food of AL mice. This would need to be verified by

>an experiment where mice on a 40% CR diet, once having reached

>maturity and their maximum 50% size, would be allowed to eat ad

>libitum, and their consumption monitored. Do these mature, small mice

>eat 70% of the food that AL mice eat? The results would allow

>modifying the CR/2 term, as necessary. Note that if CR is zero, MC =

>1, as it should be.

>

>If these arguments have any validity, the real rate of restriction of

>the 40% CR mice is 14% because of their smaller size (100 * (0.7 -

>0.6)/0.7 = 14%), although the CR mice are eating 18% more than AL mice

>on a body weight basis.

>

>I am hoping that the readers of this forum who have the inclination

>and the time to search the literature can provide data about:

>1) the mature weight of CR mice vs. AL mice for various percentages of

>CR to refine the calculation for CRW for mice started on CR at 9

>weeks, or other stages of life.

>2) provide any information about how much adult mice raised on CR

>diets eat ad libitum to refine the notion of Metabolic Capacity.

>

>CR experiments on mice show that a 40% restriction from adolescence

>results in a stunted body size which requires fewer calories in

>adulthood. From the assumptions about Metabolic Capacity, it seems

>that CR started in adulthood should probably not exceed 14%.

>

>Tony Zamora

>

[Guest guest]

Can you please provide better references than " CR Society discussion " ?

on 8/5/2004 12:31 PM, Dowling at dowlic@... wrote:

>

> This appears to be the case. From CR Society discussion:

>

> " I think this points out that being short, and therefore having a lower

> absolute calorie requirement to start with, gives one a longevity advantage

> right out of the gate - a win for the shorties among us. But I think it also

> points out that short people may find it more difficult to gain extra years

> on top of those they inherit via their practice of CR.

>

> I think it also points out the longevity challenge tall people face. There

> is no way in heck you or I are ever going to approach the absolute calorie

> numbers of a small person like Walford - even a Walford eating ad

> lib. Put another way, larger people like ourselves practicing what we might

> consider pretty torturous CR are still unlikely to exceed (or even approach)

> the lifespan of a well-nourished short person eating ad lib. Might be

> somewhat discouraging for some, particularly since in general people aren't

> envious of, or even aware of the modest lifespan advantage short people

> have. "

[Guest guest]

How's dis?

" Life Sci. 2003 Mar 7;72(16):1781-802. Related Articles, Links

Is height related to longevity?

Samaras TT, Elrick H, Storms LH.

Reventropy Associates, 11487 Madera Way, San Diego, CA 92124-2877, USA.

SamarasTT@...

Over the last 100 years, studies have provided mixed results on the

mortality and health of tall and short people. However, during the last 30

years, several researchers have found a negative correlation between greater

height and longevity based on relatively homogeneous deceased population

samples. Findings based on millions of deaths suggest that shorter, smaller

bodies have lower death rates and fewer diet-related chronic diseases,

especially past middle age. Shorter people also appear to have longer

average lifespans. The authors suggest that the differences in longevity

between the sexes is due to their height differences because men average

about 8.0% taller than women and have a 7.9% lower life expectancy at birth.

Animal experiments also show that smaller animals within the same species

generally live longer. The relation between height and health has become

more important in recent years because rapid developments in genetic

engineering will offer parents the opportunity to increase the heights of

their children in the near future. The authors contend that we should not be

swept along into a new world of increasingly taller generations without

careful consideration of the impact of a worldwide population of taller and

heavier people.

Publication Types:

Review

Review, Tutorial

PMID: 12586217 [PubMed - indexed for MEDLINE] "

>From: Francesca Skelton <fskelton@...>

>Reply-

>< >

>Subject: Re: [ ] Re: What is CRON? - 18% more food?

>Date: Thu, 05 Aug 2004 12:36:26 -0400

>

>Can you please provide better references than " CR Society discussion " ?

>

>

>on 8/5/2004 12:31 PM, Dowling at dowlic@... wrote:

> >

> > This appears to be the case. From CR Society discussion:

> >

> > " I think this points out that being short, and therefore having a lower

> > absolute calorie requirement to start with, gives one a longevity

>advantage

> > right out of the gate - a win for the shorties among us. But I think it

>also

> > points out that short people may find it more difficult to gain extra

>years

> > on top of those they inherit via their practice of CR.

> >

> > I think it also points out the longevity challenge tall people face.

>There

> > is no way in heck you or I are ever going to approach the absolute

>calorie

> > numbers of a small person like Walford - even a Walford eating

>ad

> > lib. Put another way, larger people like ourselves practicing what we

>might

> > consider pretty torturous CR are still unlikely to exceed (or even

>approach)

> > the lifespan of a well-nourished short person eating ad lib. Might be

> > somewhat discouraging for some, particularly since in general people

>aren't

> > envious of, or even aware of the modest lifespan advantage short people

> > have. "

>

[Guest guest]

Up to 5'5 " ? Sounds rather shortish to me!

>From: " citpeks " <citpeks@...>

>Reply-

>

>Subject: [ ] Re: What is CRON? - 18% more food?

>Date: Thu, 05 Aug 2004 17:28:38 -0000

>

> >>>

>From: " Dowling " <dowlic@h...>

>Date: Thu Aug 5, 2004 12:56 pm

>Subject: Re: [ ] Re: What is CRON? - 18% more food?

>How's dis?

> " Life Sci. 2003 Mar 7;72(16):1781-802. Related Articles, Links

>Is height related to longevity?

> >>>

>

>Now for the optimist's point of view: taller lives longer up to 5'5 "

>(165 cm). I suppose it depends on whether you search for longevity or

>mortality!

>

>====

>

>http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=

>Retrieve & db=pubmed & dopt=Abstract & list_uids=12859029

>Epidemiology. 2003 May;14(3):293-9.

>Height and body mass index in relation to total mortality.

>Engeland A, Bjorge T, Selmer RM, Tverdal A.

>Division of Epidemiology, Norwegian Institute of Public Health,

>Nydalen, Oslo, Norway. anders.engeland@...

>

>BACKGROUND: The relation between body mass index (BMI) and mortality

>is not clear in the literature. An inverse relation between height and

>mortality has been suggested. We explore these relations in a very

>large cohort in Norway. METHODS: We studied two million men and women,

>age 20-74 years, who were measured during 1963-2000. These persons

>were followed for an average of 22.1 years. We used proportional

>hazard models in the analyses. Also, the optimal BMI (the BMI at the

>time of measurement that was subsequently related to the lowest

>mortality) was estimated. RESULTS: Over the study period, 723,000

>deaths were registered. The relative risk of death by BMI showed a J-

>or U-shaped curve, with the lowest rates of death at BMI between 22.5

>and 25.0. In men, the optimal BMI increased from 21.6 when measured at

>age 20-29 to 24.0 when measured at age 70-74. In women, the optimal

>BMI was consistently higher, increasing from 22.2 to 25.7. Mortality

>decreased with increased height in men; in women, mortality decreased

>with height only up to heights of about 160-164 cm and then increased

>among the tallest women. CONCLUSIONS: The relation between BMI and

>mortality was J- or U-shaped, with the " optimal " BMI varying by age

>and sex. Height was inversely related to mortality in men and in women

>up to a height of 165 cm.

>

> PMID: 12859029 [PubMed - indexed for MEDLINE]

>

[Guest guest]

>From: " citpeks " <citpeks@...>

>Reply-

>

>Subject: [ ] Re: What is CRON? - 18% more food?

>Date: Thu, 05 Aug 2004 20:25:28 -0000

>

>Unfortunately, this discussion got sidetracked trying to determine

>whether short or tall people live longer. That is not the point that

>I was trying to make. I am trying to figure out how CR mice can eat

>18% more food than AL mice on a weight basis and still be calorically

>restricted.

>

>I suggest that the answer is that as the CR mice become stunted by the

>restrictive diet their smaller bodies have a smaller requirement for

>food, but their metabolic capacity decreases at a smaller rate than

>their body size, thereby creating caloric restriction. I hope that by

>understanding what happens in mice we can make better decisions for

>our own diets.

>

>For example, the Institute of Medicine suggests the *minimum* number

>of calories for a male as: Height 5'0 " , 1879 Cal, Height 5'6 " , 2114

>Cal, Height 6'0 " , 2348 Cal. These numbers apparently come from the

>base metabolic rates required to just breathe and lie down with no

>activity. I think that our practice of caloric restriction should be

>based on numbers like these that correspond to our physical structure

>and not some arbitrary number of calories like 1500 pulled out of the

>air.

Not " out of the air " at all! The less calories, the more life extension, in

a linear fashion, till one gets down below 50%-60% of " ad lib. "

>

>By understanding the animal models and how much *real* caloric

>restriction they are under, considering their size, I also feel that

>we will get a better handle on what is practical or applicable for

>humans. The experiment that I suggested to measure what an adult

>50%-size CR mouse eats at libitum could let us know the nutritional

>requirements for the mice based on their size. This may turn out to

>be equivalent to what the Institute of Medicine suggests for humans.

>In any case, the information will allow us to be more quantitative in

>our approach to CR and our understanding of the elusive " set point " ,

>etc.

>

" Set point " is, most likely, a meaningless term.

>Tony

>

>

>=======Message 14018

>From: " citpeks " <citpeks@y...>

>Date: Thu Aug 5, 2004 12:15 pm

>Subject: Re: What is CRON? - 18% more food?

>

>Mice put on a 40% calorie restricted (CR) diet after 9 weeks of age

>have an adult body weight that is 49% less than mice fed ad libitum

>(AL) (http://snipurl.com/4d7w). Considering that CR mice receive 60%

>of the food eaten by AL mice and that CR mice have an adult weight of

>51% of the weight of AL mice, CR mice eat 18% more than AL mice on a

>body weight basis.

>

>How can this information be reconciled with the fact that the degree

>of caloric restriction, within physiological limits, increases maximum

>life span proportionally? Obviously, even if the CR mice are eating

>relatively more food than AL mice, they are not eating as much as they

>need, otherwise there would be no CR longevity effect. How can we

>calculate the caloric deficit?

>

>Let us start by noting that the adult weight for CR mice is

>proportional to the degree of CR when CR is started at 9 weeks. This

>can be expressed as:

>

>CRW9 = ALW * (1 - CR) / (1 + CR/2)

>

>Where CRW9 is the weight of the adult CR mice, ALW is the weight of

>the AL mice, and CR is the caloric restriction (%CR /100). From this

>we would estimate the weight of mice on 40% CR to be half of the AL

>mice:

>

>CRW9 = ALW*(1-0.4)/(1+0.4/2) = ALW*0.6/1.2 = ALW*0.5

>

>The CR/2 term in the expression was chosen to fit the data from

>Mattson. The formula needs to be checked to see if it agrees with

>results obtained by using other degrees of caloric restriction.

>However, for the case when CR is zero, CRW = ALW, which is what we

>would expect.

>

>At this point we need to introduce the term " Metabolic Capacity " (MC)

>which would be the amount of food that can be eaten ad libitum by

>animals of a specific size. AL mice, by definition, eat exactly 100%

>of this amount. If we assume that MC decreases at a smaller rate than

>the body size of the adult animals on CR diets decreases, there will

>always be a caloric deficit for CR mice, in spite of the fact that CR

>mice eat more on a body weight basis. Let us define MC as follows:

>

>MC = (1 - CR) * (1 + CR/2)

>

>For mice on a 40% CR diet, MC = 0.6*1.2 = 0.7

>

>This can be interpreted as meaning that the adult 40% CR mice are

>getting 60% of the food of AL mice, but that ad libitum they might

>consume 70% of the food of AL mice. This would need to be verified by

>an experiment where mice on a 40% CR diet, once having reached

>maturity and their maximum 50% size, would be allowed to eat ad

>libitum, and their consumption monitored. Do these mature, small mice

>eat 70% of the food that AL mice eat? The results would allow

>modifying the CR/2 term, as necessary. Note that if CR is zero, MC =

>1, as it should be.

>

>If these arguments have any validity, the real rate of restriction of

>the 40% CR mice is 14% because of their smaller size (100 * (0.7 -

>0.6)/0.7 = 14%), although the CR mice are eating 18% more than AL mice

>on a body weight basis.

>

>I am hoping that the readers of this forum who have the inclination

>and the time to search the literature can provide data about:

>1) the mature weight of CR mice vs. AL mice for various percentages of

>CR to refine the calculation for CRW for mice started on CR at 9

>weeks, or other stages of life.

>2) provide any information about how much adult mice raised on CR

>diets eat ad libitum to refine the notion of Metabolic Capacity.

>

>CR experiments on mice show that a 40% restriction from adolescence

>results in a stunted body size which requires fewer calories in

>adulthood. From the assumptions about Metabolic Capacity, it seems

>that CR started in adulthood should probably not exceed 14%.

>

>Tony Zamora

>

[Guest guest]

Maybe I'm not following you, but it seems to me like you already answered

your own question.

It seems to me like this is all indicating that it really is an X number of

calories for everyone and not adjustable for bodyweight. If you need to eat

more because you are big, then sorry, you won't live as long as a smaller

person. It comes down to a balance of QOL and longevity. If being scrawny

doesn't impact your QOL, then more power to you (and longer life). If it

does, then you have to decide how unscrawny you need to be and eat

accordingly, understanding that lifespan is being limited by this need.

Maybe I'm misinterpreting something, but this is how it adds up in my mind.

(|-|ri5

> -----Original Message-----

> From: citpeks [mailto:citpeks@...]

> Sent: Thursday, August 05, 2004 11:25 PM

>

> Subject: [ ] Re: What is CRON? - 18% more food?

>

>

> Unfortunately, this discussion got sidetracked trying to determine

> whether short or tall people live longer. That is not the point that

> I was trying to make. I am trying to figure out how CR mice can eat

> 18% more food than AL mice on a weight basis and still be calorically

> restricted.

>

> I suggest that the answer is that as the CR mice become stunted by the

> restrictive diet their smaller bodies have a smaller requirement for

> food, but their metabolic capacity decreases at a smaller rate than

> their body size, thereby creating caloric restriction. I hope that by

> understanding what happens in mice we can make better decisions for

> our own diets.

>

> For example, the Institute of Medicine suggests the *minimum* number

> of calories for a male as: Height 5'0 " , 1879 Cal, Height 5'6 " , 2114

> Cal, Height 6'0 " , 2348 Cal. These numbers apparently come from the

> base metabolic rates required to just breathe and lie down with no

> activity. I think that our practice of caloric restriction should be

> based on numbers like these that correspond to our physical structure

> and not some arbitrary number of calories like 1500 pulled out of the

> air.

>

> By understanding the animal models and how much *real* caloric

> restriction they are under, considering their size, I also feel that

> we will get a better handle on what is practical or applicable for

> humans. The experiment that I suggested to measure what an adult

> 50%-size CR mouse eats at libitum could let us know the nutritional

> requirements for the mice based on their size. This may turn out to

> be equivalent to what the Institute of Medicine suggests for humans.

> In any case, the information will allow us to be more quantitative in

> our approach to CR and our understanding of the elusive " set point " ,

> etc.

>

> Tony

>

> >

[Guest guest]

It may not be that simple. Older individuals don't fit that formula.

on 8/5/2004 5:50 PM, Dowling at dowlic@... wrote:

>

> Not " out of the air " at all! The less calories, the more life extension, in

> a linear fashion, till one gets down below 50%-60% of " ad lib. "

>

[Guest guest]

In a message dated 8/5/04 4:30:48 PM, beccous@... writes:

n Europe, the tallest people are the Dutch who eat more dairy ( I assume the factor here is calcium for bones) than anyone in Europe and have some of the best health care.

I cannot argue with this! I was born in Holland and have eaten much dairy all my life - especially cheese. I'm five feet, five inches, and have weighed under 110 lbs. all my life (I'm presently about 106) and my bone scans are great (which surprises me, always.)

Sky

[Guest guest]

Good point! Ad lib is fairly meaningless. Any " danger " from CRON should

probably be based upon evaluation of health and function parameters (can one

perform well mentally, physically, and is one's immune system functioning

well with assessment of serology and cell counts, as well).

>From: " citpeks " <citpeks@...>

>Reply-

>

>Subject: [ ] Re: What is CRON? - 18% more food?

>Date: Fri, 06 Aug 2004 14:05:33 -0000

>

> >>>>>

>From: " Dowling " <dowlic@h...>

>Date: Thu Aug 5, 2004 5:50 pm

>Subject: Re: What is CRON? - 18% more food?

> >From: " citpeks " <citpeks@y...>

> >Date: Thu, 05 Aug 2004 20:25:28 -0000

> >I think that our practice of caloric restriction should be

> >based on numbers like these that correspond to our physical structure

> >and not some arbitrary number of calories like 1500 pulled out of the

> >air.

>Not " out of the air " at all! The less calories, the more life

>extension, in a linear fashion, till one gets down below 50%-60% of

> " ad lib. "

> >>>>

>

>,

>

>I think that the term " ad lib. " is as meaningless as " set point " . How

>many calories can you eat in a day? It depends on your appetite,

>physical activity, and choice of foods. An average size male can

>easily consume 3500 Calories per day. On that basis, 2000 calories

>per day would be a 42% CR diet. The problem is that we don't know how

>much we can eat.

>

>You say CR provides " more life ... till one gets below 50%... " . OK,

>If the average male can eat 3500 calories per day, 1500 Calories is

>57% CR. This is already *dangerous* territory if you are interested

>in life extension. Basing a diet on what you can eat ad lib., or what

>you think that you would eat ad lib. IS pulling numbers out of the

>air.

>

>I advocate basing human CR diets on individual basal metabolism once

>the BMI is in a normal range. (It does not make sense to base it on

>the basal metabolism for underweight or overweight persons.) Basal

>metabolism can be computed based on height, weight, respiration

>studies, etc. depending on the accuracy that you desire. AND it is an

>objective measure that does not depend on how hungry you are, or how

>much you think that you can eat, or other subjective factors.

>

>At the same time we have to understand the effect of CR diets started

>after maturity.

>

> >>>>

>From: " Rodney " <perspect1111@y...>

>Date: Thu Aug 5, 2004 9:17 pm

>...

>My IMPRESSION is that the percentage weight loss also exceeds percent

>restriction even when restriction is started after maturity. If this

>is correct, then 'stunting' is not the explanation. If I am wrong

>about this please feel free to straighten me out.

> >>>>

>

>From the pictures that I have seen of holocaust victims, I cannot say

>that their bones shrank during their starvation. So, there is no

>significant 'stunting' in height. However, when you consume fewer

>calories than your basal metabolism requires, there is going to be

>some emaciation as the muscles and other tissues are reduced to the

>level that can be supported by the available nutrition. The loss of

>weight may indeed be more than the percent restriction.

>

>If you are a 5'8 " male whose minimum calorie requirement is 2,200

>calories per day based on basal metabolism and sedentary life style.

>By eating only 2000 calories per day ( 10% CR) you will lose weight

>until your body adjusts to the new diet. Any additional restrictions

>to the diet should be based on your ORIGINAL basal metabolism based on

>your height, rather than your new smaller weight.

>

>I feel that a lot of the advice given on this and other boards about

>*how much* to eat does not have any scientific basis as long as " ad

>libitum " and " set point " are being used as the criteria for the diets.

> Basing the diets on OBJECTIVE physical measurements, like basal

>metabolism, height, or BMI would be more acceptable.

>

>This is why I am scrutinizing the mice experiments by using

>mathematical equations. I hope that there are generalizations that

>have applications to human diets.

>

>Tony Zamora

>

[Guest guest]

Right.

I couldn't figure out those things, so I first resolved to keep accurate track of how much I WAS eating (234# at that time). About 3200 kcals. That wasn't all I COULD eat, it was all that I WANTED to eat. Then I made the conscious decision to lower it a whole 200 calories - nothing happened. Then dropped to 2500 kcals - nothing happened, except I had to be more clever in food choices to not get hungry. Then I dropped to 2000 kcals - still not a lot happening. Then at 1800 kcals (3 yrs ago) I started losing weight. From my POV, I'd call that "calorie set point" and the 3200 ad lib.

NOW, if I drop weight, which I did, I reached a spot where I don't drop so fast. I balance at 1800 kcals at about 180#. That has no relationship to my 20 yo weight (135#). But it points out that there's a relationship between weight and calories consumed (of course), but only at that set point, since I was able to maintain the weight until I trimmed to 1800 kcals. Obvious to me, I was "wasting" calories above that point.

For the people who like numbers, that's 44% CR below "ad lib" intake. And a 25% CR in weight, below "ad lib". Now if I was to assume an intake of 1516 kcals, using the -Benedict Eq, it would support a weight of 135# plus 200 routine motion calories. 1316 + 200. Additional calories would require additional calories or weight loss.

But when I was 20yo, I required 1647 +200 kcals. So I would eat now 18% fewer calories than at 20 yo for 135#. Maybe that's what Walford meant by CR.

I just have a "gut feeling" that somewhere near 1800 calories is the wright place for me.

And each year I need to drop that 7 kcals (per H-B Eq).

Regardless what a person selects, it has to provide the level of QOL he demands.

Regards.

----- Original Message -----

From: citpeks

Sent: Friday, August 06, 2004 9:05 AM

Subject: [ ] Re: What is CRON? - 18% more food?

,I think that the term "ad lib." is as meaningless as "set point". Howmany calories can you eat in a day? It depends on your appetite,physical activity, and choice of foods. An average size male caneasily consume 3500 Calories per day. On that basis, 2000 caloriesper day would be a 42% CR diet. The problem is that we don't know howmuch we can eat.

[Guest guest]

25 BMI may not be " normal, " but in the US, it's pretty near the mean!

http://www.halls.md/bmi/nhanes.htm

>From: " old542000 " <apater@...>

>Reply-

>

>Subject: [ ] Re: What is CRON? - 18% more food?

>Date: Fri, 06 Aug 2004 23:36:07 -0000

>

>Hi All,

>

>1. I believe that the 25 BMI classification as normal is a high

>estimate.

>

>I lost weight from 152 pounds at age 20 to less than 100 pounds, and

>I eat over 1800 calories/day.

>

>Cheers, Al Pater.

>

>--- In , " Rodney " <perspect1111@y...>

>wrote:

> > Hi Tony:

> >

> > These are interesting issues you raise. Certainly it would be much

> > better if we had an objecive way to determine what constitutes 40%

> > restriction for each of us (or 20% restriction, or whatever). A

> > major problem, I think, is that everyone is different.

> >

> > A few thoughts: In my case, perhaps I am unusual, there is nothing

> > vague about the term 'Set point'. I believe my set point is my

> > weight at age 22 when I was doing ~20 hours a week of fairly

>intense

> > training for endurance sports. That happened to be 173 pounds. It

> > is the weight I believed all my life until a couple of years ago to

> > be my ideal weight. That number was confirmed, incidentally, by

> > formulae relating 'ideal' weight to height and wrist

>circumference.

> > In the past whenever I have found I am five or ten pounds over that

> > weight, I have taken steps to return it to 173 pounds.

> >

> > On the other hand, for me the term 'Ad lib' is definitely vague. I

> > could easily eat 3500 calories a day, and more if I put my mind to

> > it - and I would put on (quite literally) hundreds of pounds of

> > weight per year if I did so. So let me suggest to you an

>alternative

> > measure which I think makes more sense as a substitute for 'ad

>lib'.

> > I will call it 'con ad stab'. That is short for 'conventional ad

> > stable'.

> >

> > Walford and everyone else who uses the term 'ad lib' is looking for

>a

> > benchmark measure of food consumed for a person who is neither over

> > weight according to the conventional wisdom, nor excessively slim.

> > So perhaps the benchmark number of calories from which to calculate

> > degrees of restriction should be that number which MAINTAINS WEIGHT

> > at what the conventional wisdom considers to be ideal weight.

> >

> > More specifically, I would define 'con ad stab' as the number of

> > calories needed to maintain weight in the general vicinity of BMI =

> > 25; WC/H = 0.500; BF% = 21%. (These are my perception of what the

> > conventional wisdom thinks are about right for people who are

>neither

> > over weight nor excessively slim). Perhaps not coincidentally,

>those

> > numbers (the BMI = 25; WC/H = 0.500; and BF% = 21%) coincide very

> > closely in my case with what I believe to be my set point - 173

> > pounds.

> >

> > It would be interesting to know whether or not that is also true

>for

> > others. If this happy coincidence does not only apply to me, then

> > perhaps we 'have something'. If everyone's numbers are all over

>the

> > lot, then obviously we don't.

> >

> > Whatever that number of calories turns out to be (perhaps it was

>2000

> > per day for me a year ago, required to maintain my weight at those

> > three parameters) degrees of restriction can be calculated from

> > there. In my case 40% restriction would be 1200 calories. (More

> > extreme than I am prepared to try in the absence of much more

> > information).

> >

> > Does this help?

>

[Guest guest]

>>25 BMI may not be " normal, " but in the US, it's pretty near the mean!

It seems like somewhere between 18-22 may be the healthiest.....

First....

" Impact of Overweight on the Risk of Developing Common Chronic Diseases

During a 10-Year Period Arch Intern Med. 2001;161:1581-1586

Alison E. Field, ScD; et al

Conclusions: During 10 years of follow-up, the incidence of diabetes,

gallstones, hypertension, heart disease, colon cancer, and stroke (men

only) increased with degree of overweight in both men and women. Adults who were

overweight but not obese (ie, 25.0BMI29.9) were at

significantly increased risk of developing numerous health conditions. Moreover,

the dose-response relationship between BMI and the risk of

developing chronic diseases was evident even among adults in the upper half of

the healthy weight range (ie, BMI of 22.0-24.9), suggesting

that adults should try to maintain a BMI between 18.5 and 21.9 to minimize their

risk of disease.

Second.....

Relation between body mass index and mortality in an unusually slim cohort

M Thorogood, P N Appleby, T J Key, J Mann

J Epidemiol Community Health 2003;57:130-133

Conclusions: Lean men and women (BMI <18 kg/m2) experience increased all cause

mortality compared

with those with a BMI between 20 and 22 kg/m2. This pattern is not seen for

cancer mortality,

but is found for cardiovascular and respiratory diseases.

I emailed one of the authors, Appleby, when this came out and this is what

he sent in response to my question..

" " The death rate ratios were adjusted for age at recruitment, sex, smoking, and

pre-existing cardiovascular disease or diabetes.

Further, the same pronounced upturn in mortality among the very slim (BMI<18

kg/m2) was found among men, women, vegetarians,

non-vegetarians, never smokers, and subjects aged less than 60 at recruitment,

and after excluding the first 5 years of follow-up.

Deaths from accidents & violence were included in the " all other causes of

death " category. Mortality from this *cause* was also

significantly higher in the slimmest category (BMI<18) compared with the

reference category (BMI 20-22). " "

[Guest guest]

----- Original Message -----

From: old542000

Sent: Saturday, August 07, 2004 3:59 PM

Subject: [ ] Re: What is CRON? - 18% more food?

Hi All,I prefer long term prospective studies such as:In a 12-year prospective study, the authors examined the relation between body mass index (BMI) and mortality among the 20,346 middle-aged (25-54 years) and older (55-84 years) non-Hispanic white cohort members of the Adventist Health Study (California, 1976-1988) who had never smoked cigarettes and had no history of coronary heart disease, cancer, or stroke. In analyses that accounted for putative indicators (weight change relative to 17 years before baseline, death during early follow-up) of pre-existing illness, the authors found a direct positive relation between BMI and all-cause mortality among middle-aged men (minimum risk at BMI (kg/m2) 15-22.3, older men (minimum risk at BMI 13.5-22.3), middle-aged women (minimum risk at BMI 13.9-20.6), and older women who had undergone postmenopausal hormone replacement (minimum risk at BMI 13.4-20.6). Among older women who had not undergone postmenopausal hormone replacement, the authors found a J-shaped relation (minimum risk at BMI 20.7-27.4) in which BMI <20.7 was associated with a twofold increase in mortality risk (hazard ratio (HR) = 2.2, 95% confidence interval (CI) 1.3, 3.5) that was primarily due to cardiovascular and respiratory disease. These findings not only identify adiposity as a risk factor among adults, but also raise the possibility that very lean older women can experience an increased mortality risk that may be due to their lower levels of adipose tissue-derived estrogen.> >>25 BMI may not be "normal," but in the US, it's pretty near the mean!> > It seems like somewhere between 18-22 may be the healthiest.....> > First....>

[Guest guest]

The BMI categories used in this study are rather broad. I'd like to see

stratification of the lower ranges (BMI 15-17, 18-20, 21-23).

>From: " old542000 " <apater@...>

>Reply-

>

>Subject: [ ] Re: What is CRON? - 18% more food?

>Date: Sat, 07 Aug 2004 23:59:40 -0000

>

>Hi All,

>

>Studies have corrected for early deaths due to underlying diseases by

>eliminating the first 17 years, and found a linear relationship.

>This, is long-term.

>

>heers, Al Pater.

>

>

> > > >>25 BMI may not be " normal, " but in the US, it's pretty near

>the

> > mean!

> > >

> > > It seems like somewhere between 18-22 may be the healthiest.....

> > >

> > > First....

> > >

>