Re: %CR and body size (was Accuracy of Formulas...)

[Guest guest]

citpeks wrote:

>

> I don't think

> that any adult should adopt CR diets in excess of 16 or 17 percent.

>

Isn't this pretty much what the good doctor Walford recommended? i.e.

take your high school weight minus 15% as a goal weight?

Positive Dennis

> That is my opinion. I have some of this information with references

> on my CR page.

> http://www.scientificpsychic.com/health/crondiet.html

>

>

> Tony

>

>

>

>

>

>

[Guest guest]

Hi Tony:

Well I do not agree. I think drawing conclusions from animal studies

in which CR was started before full growth was attained (especially

if implemented very early in life) has little if any relevance to

people over the age of 25 who are doing, or thinking of doing, CR.

As far as I know, no one here is thinking of trying to grow a bonsai

human.

[but I do not in any way doubt that if CR were to be started in

humans soon after weaning they would have small stature. A limited

food supply in the poorer countries in South America results in many

of that population being very noticeably perhaps a foot shorter than

us better fed in North America.]

Nor do I believe there is reason to suppose it is advisable to limit

CR to an intake of at most only 16% or 17% less than ad lib.

We know - posted here about a year ago, Dr. Barbara Hansen - that

monkeys put on 30% CR at the human-equivalent age of 50, appear to be

living 30% longer than those permitted to feed ad lib.

We also know that in Spindler's study (PMID: 15044709) where mice

were put on CR at the human-equivalent age of ~60 years (see post

#11210 and subsequent) their mortality rate was halved, and average

and maximum lifespans were both appreciably extended.

In that Spindler study, the control mice were fed 10% less than mice

are normally considered to need. And the CR mice were fed a very

substantial ***49.5% less*** than what is regarded as a normal feed

allocation. Yet these '60-year old' CR mice positively thrived at

that degree of restriction.

In addition, there are people many of us are familiar with, who are

on 40% or higher restriction, and none of them weigh anywhere

remotely close to 50 or 75 pounds, which were the numbers I

calculated using H-B and M-S for males. The numbers would be lower

still for females, so strongly suggesting, imo, that they are not

realistic.

So empirical reality, at least the cases I have specifed above, do

not seem to me to be consistent with your view. But if there are

other papers with empirical data for subjects where CRON was started

after full growth had been achieved that disagree with the papers I

have posted above then I will be happy to take a look at them.

Rodney.

> > You often make this claim - that mice on 40% CR grow to being

half

> > the size of mice fed ad lib. But am I right in believing that

that

> > is only true if the mice are put on CR at a very early age, like

> > shortly after weaning?

> >

> > And if I am correct about that, then why do you believe this has

> > relevance to humans? I have never seen or heard of anyone say

they

> > were put on CR shortly after weaning; nor have I seen anyone say

> > they

> > are thinking of doing it with their child; and certainly no one I

am

> > aware of who knows anything about CR recommends such a practice.

So

> > what is it about this mouse example that you feel has relevance

for

> > people at ?

> >

> > I very much doubt anyone here would recommend even considering

> > starting CR at least until they have become fully grown on a

regular

> > diet.

> >

>

> Rodney,

>

> It is a fact that mice on 40% CR grow to being half the size of mice

> fed ad lib. Just look at the Figure 1 of Mattson's paper:

> http://www.pnas.org/cgi/content/full/100/10/6216

>

> A high degree of Caloric Restriction stunts growth when applied from

> an early age. Why is this relevant for the people at

?

> Here is my opinion:

>

> In nature everything seeks its balance. If you plant a maple

seedling

> in a 1 gallon pot, you will have a small bonsai at the end of 15

> years. If you plant an identical seedling in a field, you will

have a

> 30-foot full grown tree in 15 years. The resources available to the

> tree determine its development. CR works in the same way. The

amount

> of nutrients available (the environmental factors) supersede the

> genetic factors that control growth.

>

> If we plant the bonsai in a field after 15 years, the tree will grow

> further. A person who starts eating ad lib after being on CR will

> start to gain weight.

>

> However, if you try to restrict the resources of the full-size tree

to

> those of a smaller tree, the big tree can readily wither or die.

Call

> it " transplant shock " or whatever. I think that something similar

can

> happen with humans if the degree of caloric restriction is too

great.

> There will be a loss of weight as the muscles shrink, the bone mass

> diminishes, and maybe even as the brain fat is depleted.

>

> If you take a look at the Mifflin-St Jeor energy equations for a

> 5-foot, 8-inch 35-year-old human male with a BMI of 22.0, the BMR is

> 1565 Calories. A person of half the weight (72.2 pounds) and a

height

> of 4 feet, 0 inches, also corresponding to a BMI of 22.0, would

have a

> BMR of 919 Calories. Calculating the percentage: 100(919/1565), we

> get 59 percent. Surprise! A half-size human requires ~60% of the

> calories of the full-size human, i.e., a 40%CR diet. Is it only

> coincidence that this is the same as the mouse data? I don't think

so.

>

> So what happens if a full size mature human starts eating the diet

for

> a half-size human? Keys' Minnesota starvation studies provide the

> answer. The body adapts by consuming its own tissues and reducing

the

> BMR of metabolically active tissue by up to 16%. If the caloric

> restriction exceeds the amount by which the body can adjust its

> metabolism, the body starts wasting away, and you eventually starve

to

> death if a balance is not reached. I think that CR beyond the

ability

> of the body to adapt will cause more harm than good. I don't think

> that any adult should adopt CR diets in excess of 16 or 17 percent.

>

> That is my opinion. I have some of this information with references

> on my CR page.

> http://www.scientificpsychic.com/health/crondiet.html

>

>

> Tony

>

[Guest guest]

>

> In addition, there are people many of us are familiar with, who are

> on 40% or higher restriction, and none of them weigh anywhere

> remotely close to 50 or 75 pounds, which were the numbers I

> calculated using H-B and M-S for males. The numbers would be lower

> still for females, so strongly suggesting, imo, that they are not

> realistic.

>

Rodney,

You cannot use the energy equations on CRed individuals. The

equations overestimate substantially because CR decreases BMR. My %CR

calculator only uses the equation for the control, which is supposed

to be normal.

I really don't think that there are many people who are practicing 40%

or more CR. A lot of people don't know how to count the calories in

food or the calories spent through exercise accurately, and others

don't know how to calculate %CR.

There are a few extreme CRONies, but in all cases they have very

little muscle. Liza May practices about 43%CR (on the right in the

following picture). I know that she knows how to count calories

because she is a nutritionist.

http://health.ph./group/ /photos/view/e053?b=6

Maybe Walford also practices extreme CR. Her picture during a

promotional interview in 2005 showed a face musculature like what you

find in biology books, but the picture on the CRS web site shows her

with a little bit more fat:

http://www.scientificpsychic.com/ads/lisa.html

Our good friend, Al Pater, may also practice a high degree of CR, but

as you know, he has had severe health problems. Ralph Cornell, who

recently died, was estimated by Mcglothin to eat only 600 to 800

Calories per day.

Unfortunately, we don't have much data about the Percent CR for humans

because some people are reluctant to publish their figures and others

refuse to calculate it.

Tony

[Guest guest]

Yes, he did, but he did not take into account that some people may have been too light already. Like a skinny 6 ft, 135#. I have 2 gsons exactly that weight at 18/20, and they look I did - skinny as anyone can want to be.

I can't imagine anyone dieting to lose weight at that point.

BTW, I don't intend to force my weight back to that.

Regards.

Re: [ ] %CR and body size (was Accuracy of Formulas...)

citpeks wrote:>> I don't think> that any adult should adopt CR diets in excess of 16 or 17 percent.> Isn't this pretty much what the good doctor Walford recommended? i.e. take your high school weight minus 15% as a goal weight?Positive Dennis

..

[Guest guest]

Tony: How old was “Ralph Cornell”? What did he die of? I assume he “claimed” to be practising CR? ON? (I do not know of him).

--------------------------

Our good friend, Al Pater, may also practice a high degree of CR, but

as you know, he has had severe health problems. Ralph Cornell, who

recently died, was estimated by Mcglothin to eat only 600 to 800

Calories per day.

Unfortunately, we don't have much data about the Percent CR for humans

because some people are reluctant to publish their figures and others

refuse to calculate it.

Tony

[Guest guest]

Ralph Cornell was the oldest member of the Calorie Restriction Society

and died earlier this month at age 104. Mcglothin, who reported

his death to the CRS, indicated that Ralph's nutrition was probably

inadequate and that both his heart and kidneys had begun to fail

during the last few weeks. Although he had been feeble, in recent

months he met with some CRS representatives who congratulated him on

his 104th birthday.

May we all live so long!

Tony

>

> > Tony: How old was ³Ralph Cornell²? What did he die of? I assume

he ³claimed²

> > to be practising CR? ON? (I do not know of him).

> >

> > --------------------------

> >

> > Our good friend, Al Pater, may also practice a high degree of CR, but

> > as you know, he has had severe health problems. Ralph Cornell, who

> > recently died, was estimated by Mcglothin to eat only 600 to 800

> > Calories per day.

> >

> > Unfortunately, we don't have much data about the Percent CR for humans

> > because some people are reluctant to publish their figures and others

> > refuse to calculate it.

> >

> > Tony

>

[Guest guest]

I agree with Jim here. If I tried to go 15% below my high school

weight, my BMI would be 15.1. Even reaching my high school weight

would put me at BMI=17.7. Neither seems very healthy to me, and I'm

sure my osteoporosis would get a lot worse.

Diane

> >

> > I don't think

> > that any adult should adopt CR diets in excess of 16 or 17 percent.

> >

> Isn't this pretty much what the good doctor Walford recommended? i.e.

> take your high school weight minus 15% as a goal weight?

>

> Positive Dennis

>

> .

>

[Guest guest]

Hi Tony:

If, as you claim, energy equations cannot be used on CR'd individuals

because they have a lowered BMR, then they cannot be used on ANYONE

because, as we have discussed here at length many times, lean body

mass rises and falls substantially with changes in total body

weight. So the equations would not apply to overweight or obese

people either, since their BMRs are increased by their higher LBM.

If what you say were true then there would be only one BMI at which

these equations are valid, which clearly would make complete nonsense

of them, and which, I think, would surprise their authors and the

many serious people who use them and find them useful much of the

time (for higher weight people).

Of course in fact they **do** apply to over weight and obese people

because they **measured** the caloric expenditures of such people.

That is how they derived the equations in the first place. But it is

doubtful they had many slim people in the groups they measured, and

the equation may effectively, and inappropriately, straight-line the

data at lower BMIs. That is my best guess as to why the equations

very clearly give very wrong answers at lower caloric intakes as I

demonstrated. (Email conversations with Dr.s Mifflin and St. Jeor

did not help resolve this question).

You mention the two s and other cases of more extreme CR. We can

all agree that the 600-800 calories in one case you mention is

ridiculous and likely to result in death. Similarly we know of

health problems short of death from inadequate nutrition, of either

macro or micronutrients. The s have chosen to go further in the

direction of an extreme than most of us have chosen. They have gone

further than I am prepared to go, or that I would advise others to

go. As I have suggested before, they will either live to be 140 or

die early, and I do not know which. But that is not, imo, a valid

reason to warn against more than what you call '17% restriction'.

[i also have a problem with your definition of 'degree of

restriction'. All the papers I have read look at what ad lib intakes

are and then judge percent restriction in relation to that. You seem

to base yours on something entirely different. You do not seem to

use the concept of ad lib. My ad lib intake is ~3300 calories a day,

for example. I recently measured it. So for me, 40% restriction is

somewhat less than 2000 calories.]

In my case, consuming a mere 700 calories would be 79% restriction.

I sincerely hope we all know that is absurd. It has no relevance to

people eating, or considering eating, 30% or 49% less than ad lib as

in the monkey and mouse experiments. But we do not have good data to

tell us where the danger threshold lies. Which is absolutely an

excellent reason to be cautious. But clearly, based on the best

information we have to date, 30% or 40%, (or possbly even 50%

apparently) is not excessive, in relation to ad lib, as seen from the

excellent health status of the mice and monkeys which were past

middle age, like many of us, at initiation of those degrees of CR.

> Unfortunately, we don't have much data about the Percent CR for

> humans because some people are reluctant to publish their figures

> and others refuse to calculate it.

There are quite a few people elsewhere on the net, as well as here,

who know a great deal about how to count calories, and some have

published their data. My bet is that not many of them know

accurately what their **ad lib** intake is.

But calculating percent CR is dead easy if you know your ad lib

intake:

Percent CR = calories consumed ÷ ad lib x 100

In my case that is: 1900 ÷ 3300 x 100

But we do not need to rely on any single indicator to judge the

desirability of a given level of caloric intake. There are plenty of

others including the resulting: lipids values; blood pressure

(including pulse pressure) ; WBC; fasting glucose; fasting insulin;

CRP; ratios of waist to height and waist to 'hip'; BF%; ..........

yes, even BMI ! And unequivocal evidence of nutritional adequacy is

also very important and is less easy to achieve at lower levels of

intake. This of course has been repeatedly emphasized here,

especially by Francesca.

At some stage our CRON effort may progress to the point where the

numbers look good enough that we can ask: " Do I really need to get

these numbers any better? Or might I be running some risk in trying

to improve them further? " And the willingness or desire to accept

risk varies from one individual to another. As an example, we all

here know well that a large percentage of the population seem willing

to accept, without much concern, the obviously substantial risks of

maintaining a BMI of 30. We are here because we consider that to be

a risk we cannot accept.

On risk thresholds, as much else, we have to make our own decisions

in a world of incomplete information.

Rodney.

>

> >

> > In addition, there are people many of us are familiar with, who

are

> > on 40% or higher restriction, and none of them weigh anywhere

> > remotely close to 50 or 75 pounds, which were the numbers I

> > calculated using H-B and M-S for males. The numbers would be

lower

> > still for females, so strongly suggesting, imo, that they are not

> > realistic.

> >

>

> Rodney,

>

> You cannot use the energy equations on CRed individuals. The

> equations overestimate substantially because CR decreases BMR. My %

CR

> calculator only uses the equation for the control, which is supposed

> to be normal.

>

> I really don't think that there are many people who are practicing

40%

> or more CR. A lot of people don't know how to count the calories in

> food or the calories spent through exercise accurately, and others

> don't know how to calculate %CR.

>

> There are a few extreme CRONies, but in all cases they have very

> little muscle. Liza May practices about 43%CR (on the right in the

> following picture). I know that she knows how to count calories

> because she is a nutritionist.

>

http://health.ph./group/ /photos/view/e05

3?b=6

>

> Maybe Walford also practices extreme CR. Her picture during a

> promotional interview in 2005 showed a face musculature like what

you

> find in biology books, but the picture on the CRS web site shows her

> with a little bit more fat:

> http://www.scientificpsychic.com/ads/lisa.html

>

> Our good friend, Al Pater, may also practice a high degree of CR,

but

> as you know, he has had severe health problems. Ralph Cornell, who

> recently died, was estimated by Mcglothin to eat only 600 to

800

> Calories per day.

>

> Unfortunately, we don't have much data about the Percent CR for

humans

> because some people are reluctant to publish their figures and

others

> refuse to calculate it.

>

> Tony

>

[Guest guest]

Hi folks:

LOL. Correction. The section in the middle should have read:

" But calculating percent CR is dead easy if you know your ad lib

intake:

Percent CR = 100 - (calories consumed ÷ ad lib x 100)

In my case that is: 100 - (1900 ÷ 3300 x 100) "

Sorry about that!

Rodney.

> >

> > >

> > > In addition, there are people many of us are familiar with, who

> are

> > > on 40% or higher restriction, and none of them weigh anywhere

> > > remotely close to 50 or 75 pounds, which were the numbers I

> > > calculated using H-B and M-S for males. The numbers would be

> lower

> > > still for females, so strongly suggesting, imo, that they are

not

> > > realistic.

> > >

> >

> > Rodney,

> >

> > You cannot use the energy equations on CRed individuals. The

> > equations overestimate substantially because CR decreases BMR.

My %

> CR

> > calculator only uses the equation for the control, which is

supposed

> > to be normal.

> >

> > I really don't think that there are many people who are

practicing

> 40%

> > or more CR. A lot of people don't know how to count the calories

in

> > food or the calories spent through exercise accurately, and others

> > don't know how to calculate %CR.

> >

> > There are a few extreme CRONies, but in all cases they have very

> > little muscle. Liza May practices about 43%CR (on the right in

the

> > following picture). I know that she knows how to count calories

> > because she is a nutritionist.

> >

>

http://health.ph./group/ /photos/view/e05

> 3?b=6

> >

> > Maybe Walford also practices extreme CR. Her picture during

a

> > promotional interview in 2005 showed a face musculature like what

> you

> > find in biology books, but the picture on the CRS web site shows

her

> > with a little bit more fat:

> > http://www.scientificpsychic.com/ads/lisa.html

> >

> > Our good friend, Al Pater, may also practice a high degree of CR,

> but

> > as you know, he has had severe health problems. Ralph Cornell,

who

> > recently died, was estimated by Mcglothin to eat only 600 to

> 800

> > Calories per day.

> >

> > Unfortunately, we don't have much data about the Percent CR for

> humans

> > because some people are reluctant to publish their figures and

> others

> > refuse to calculate it.

> >

> > Tony

> >

>

[Guest guest]

> Rodney wrote:

> I also have a problem with your definition of 'degree of

> restriction'. All the papers I have read look at what ad lib intakes

> are and then judge percent restriction in relation to that. You seem

> to base yours on something entirely different. You do not seem to

> use the concept of ad lib. My ad lib intake is ~3300 calories a day,

> for example. I recently measured it. So for me, 40% restriction is

> somewhat less than 2000 calories.

> ...

> But calculating percent CR is dead easy if you know your ad lib

> intake:

>

> Percent CR = 100 - (calories consumed ÷ ad lib x 100)

> In my case that is: 100 - (1900 ÷ 3300 x 100)

This is exactly the type of misconception about %CR for humans that I

was talking about. You claim to practice 42.4%CR because you can eat

3300 calories ad lib.

The correct formula for Percent CR should use control calories and not

ad lib calories:

Percent CR = 100 - (calories_consumed ÷ control_calories x 100)

As you yourself have mentioned before in several postings, in clinical

experiments researchers try not to overfeed the mice to prevent them

from having obesity-related diseases that confound the results of the

experiment. You can see in Mattson's chart how the " ad lib " mice were

fed approximately 3.7 grams of food per day consistently for the

duration of the experiment:

http://www.pnas.org/cgi/content/full/100/10/6216/F1

The controls should not be obese, i.e., they should have a normal

weight. If you use as a control a person who overeats, your percent

CR is going to look stellar, but it is going to be wrong.

Let us assume that you are a 64-year old male, weighing 137 pounds,

who is moderately active and eats 1900 calories per day. Should you

be comparing yourself with someone who can eat 3300 calories? I don't

think so. You should compare yourself with someone just like you

whose weight is in the middle of the normal BMI range. Such a person

requires 2200 calories and not 3300. So your percent CR is

100 - (1900 ÷ 2200 x 100) = ~13.5% CR

If you compare yourself with someone just like you but whose weight is

164 pounds (BMI 25, just above the normal range) the control calories

would be 2340. So comparing yourself with the heaviest normal gives a

percent CR of ~18.8%.

These lower numbers do not diminish your accomplishment, it only puts

in perspective how severe a 40%CR diet is. To practice a 40%CR diet

compared to a control in the middle of the normal BMI range you would

have to eat 1320 calories per day while remaining moderately active.

Overstating the amount of activity is another way to inflate the %CR

numbers. If you say that you are moderately active, but in reality

you are only lightly active, your percent CR is actually 2.7%.

This is why I said before that I don't know many people who practice a

very high degree of restriction. Many may claim that they do, but

they generally don't pass the test of objective measurements.

Tony

Calorie Restriction Calculator:

http://www.scientificpsychic.com/health/cron1.html

[Guest guest]

I think Walford's " set point " weight is much more similar to Tony's

control calorie model than to Rodney's ad lib model. Walford

calculated %CR as

%CR = 100 x (calories to maintain set point - calories

eaten)/(calories to maintain set point).

The calories to maintain the set point weight cannot be an amount that

causes one to gain weight. Rodney, you stated in an earlier post that

if you ate your " ad lib " amount of calories, you'd eventually weight

350 pounds. That is not a set point. The set point number of

calories should be whatever number of calories you were eating to

maintain your weight before you began CR.

My set point weight is lower than Tony's control model (BMI-22.5)

though, because my BMI has never been as high as 22.5. But I can see

how you would choose that number as a control model, since the concept

of set point is vague and confusing.

Diane

> > I also have a problem with your definition of 'degree of

> > restriction'. All the papers I have read look at what ad lib intakes

> > are and then judge percent restriction in relation to that. You seem

> > to base yours on something entirely different. You do not seem to

> > use the concept of ad lib. My ad lib intake is ~3300 calories a day,

> > for example. I recently measured it. So for me, 40% restriction is

> > somewhat less than 2000 calories.

> > ...

> > But calculating percent CR is dead easy if you know your ad lib

> > intake:

> >

> > Percent CR = 100 - (calories consumed ÷ ad lib x 100)

> > In my case that is: 100 - (1900 ÷ 3300 x 100)

>

>

> This is exactly the type of misconception about %CR for humans that I

> was talking about. You claim to practice 42.4%CR because you can eat

> 3300 calories ad lib.

>

> The correct formula for Percent CR should use control calories and not

> ad lib calories:

>

> Percent CR = 100 - (calories_consumed ÷ control_calories x 100)

>

> As you yourself have mentioned before in several postings, in clinical

> experiments researchers try not to overfeed the mice to prevent them

> from having obesity-related diseases that confound the results of the

> experiment. You can see in Mattson's chart how the " ad lib " mice were

> fed approximately 3.7 grams of food per day consistently for the

> duration of the experiment:

> http://www.pnas.org/cgi/content/full/100/10/6216/F1

>

> The controls should not be obese, i.e., they should have a normal

> weight. If you use as a control a person who overeats, your percent

> CR is going to look stellar, but it is going to be wrong.

>

> Let us assume that you are a 64-year old male, weighing 137 pounds,

> who is moderately active and eats 1900 calories per day. Should you

> be comparing yourself with someone who can eat 3300 calories? I don't

> think so. You should compare yourself with someone just like you

> whose weight is in the middle of the normal BMI range. Such a person

> requires 2200 calories and not 3300. So your percent CR is

> 100 - (1900 ÷ 2200 x 100) = ~13.5% CR

>

> If you compare yourself with someone just like you but whose weight is

> 164 pounds (BMI 25, just above the normal range) the control calories

> would be 2340. So comparing yourself with the heaviest normal gives a

> percent CR of ~18.8%.

>

> These lower numbers do not diminish your accomplishment, it only puts

> in perspective how severe a 40%CR diet is. To practice a 40%CR diet

> compared to a control in the middle of the normal BMI range you would

> have to eat 1320 calories per day while remaining moderately active.

>

> Overstating the amount of activity is another way to inflate the %CR

> numbers. If you say that you are moderately active, but in reality

> you are only lightly active, your percent CR is actually 2.7%.

>

> This is why I said before that I don't know many people who practice a

> very high degree of restriction. Many may claim that they do, but

> they generally don't pass the test of objective measurements.

>

> Tony

>

> Calorie Restriction Calculator:

> http://www.scientificpsychic.com/health/cron1.html

>

[Guest guest]

Hi Tony:

First, could you please tell me where you get your definition of " ad

libitum " ? In particular where it is defined the way you appear to

define it, as " the amount eaten by slim individuals " . Because the

people you use as representing ad lib, those in the middle of the so-

called 'normal' (18.5 - 24.9) range, are slim by comparison with

almost everyone else in the community.

In contrast, the definition in the Medline dictionary is:

" Main Entry: ad lib

Pronunciation: ad-lib

Function: adverb

: without restraint or imposed limit : as much or as often as is

wanted <the animals were given water ad lib -- Science> -- often used

in writing prescriptions " .

So Medline says ad lib is " without restraint, as much or as often as

is wanted. " Is it your opinion that the Medline dictionary is wrong?

In almost all the CR studies I have read, the investigators have

examined the lifespans, and other characteristics, of CRON animals

compared with animals that are provided food 24 hours a day, so that

they can eat as much as they want whenever they want.

Yes, there was a study where the investigators fed the controls 10%

less than ad lib. The reason was because they wanted to counter an

objection which had been raised regarding previous studies that the

reason the CRON animals had lived longer might be because the control

animals were over weight. It was not because they thought that the

definition of ad lib was: " make sure they don't eat too much " .

Very simply, in for example the monkey study - Hansen et al - the

control monkeys are fed three meals a day and eat as much as they

wish. The CRON monkeys are fed 30% less than that. The

investigators describe feeding the CRON monkeys 30% less than the

monkeys eating as much as they want: " 30% CR " .

Similarly, with the studies in mice and rats that restricted intake

by various percentages. Similarly with the fruit fly experiments at

University College, London. Where the restricted flies were fed 40%

less than flies have been found to normally eat. They do not judge

the intake of their CR flies in comparison with the amount slim flies

consume. But if you find papers where that is what was done, please

post them.

You are free, obviously, to calculate whatever you want whatever way

you wish. But when the papers we all rely on for information about

the health effects, and risks, of various degrees of restriction use

the Medline definition, and you use a definition of your own that is

entirely different, it can be seriously misleading. Especially when

you keep saying that 16% restriction is the maximum that is healthy

for humans without pointing out that your definition of percent CR is

entirely different from the definitions used in the studies we rely

on. In those studies 30%, 40% or 50% restriction, based on the

Medline definition of ad lib, has been found to be hugely beneficial

in animals, including some that are very closely related to us.

Rodney.

> > I also have a problem with your definition of 'degree of

> > restriction'. All the papers I have read look at what ad lib

intakes

> > are and then judge percent restriction in relation to that. You

seem

> > to base yours on something entirely different. You do not seem to

> > use the concept of ad lib. My ad lib intake is ~3300 calories a

day,

> > for example. I recently measured it. So for me, 40% restriction is

> > somewhat less than 2000 calories.

> > ...

> > But calculating percent CR is dead easy if you know your ad lib

> > intake:

> >

> > Percent CR = 100 - (calories consumed ÷ ad lib x 100)

> > In my case that is: 100 - (1900 ÷ 3300 x 100)

>

>

> This is exactly the type of misconception about %CR for humans that

I

> was talking about. You claim to practice 42.4%CR because you can

eat

> 3300 calories ad lib.

>

> The correct formula for Percent CR should use control calories and

not

> ad lib calories:

>

> Percent CR = 100 - (calories_consumed ÷ control_calories x 100)

>

> As you yourself have mentioned before in several postings, in

clinical

> experiments researchers try not to overfeed the mice to prevent them

> from having obesity-related diseases that confound the results of

the

> experiment. You can see in Mattson's chart how the " ad lib " mice

were

> fed approximately 3.7 grams of food per day consistently for the

> duration of the experiment:

> http://www.pnas.org/cgi/content/full/100/10/6216/F1

>

> The controls should not be obese, i.e., they should have a normal

> weight. If you use as a control a person who overeats, your percent

> CR is going to look stellar, but it is going to be wrong.

>

> Let us assume that you are a 64-year old male, weighing 137 pounds,

> who is moderately active and eats 1900 calories per day. Should you

> be comparing yourself with someone who can eat 3300 calories? I

don't

> think so. You should compare yourself with someone just like you

> whose weight is in the middle of the normal BMI range. Such a

person

> requires 2200 calories and not 3300. So your percent CR is

> 100 - (1900 ÷ 2200 x 100) = ~13.5% CR

>

> If you compare yourself with someone just like you but whose weight

is

> 164 pounds (BMI 25, just above the normal range) the control

calories

> would be 2340. So comparing yourself with the heaviest normal

gives a

> percent CR of ~18.8%.

>

> These lower numbers do not diminish your accomplishment, it only

puts

> in perspective how severe a 40%CR diet is. To practice a 40%CR diet

> compared to a control in the middle of the normal BMI range you

would

> have to eat 1320 calories per day while remaining moderately active.

>

> Overstating the amount of activity is another way to inflate the %CR

> numbers. If you say that you are moderately active, but in reality

> you are only lightly active, your percent CR is actually 2.7%.

>

> This is why I said before that I don't know many people who

practice a

> very high degree of restriction. Many may claim that they do, but

> they generally don't pass the test of objective measurements.

>

> Tony

>

> Calorie Restriction Calculator:

> http://www.scientificpsychic.com/health/cron1.html

>

[Guest guest]

I would like to re post my Message #17834 From Mar 4,

2005 on this topic.

My comments still apply.

Thanks

Jeff

Message #17834 From Mar 4, 2005

RE: [ ] Why do plateaus happen?

>>In my opinion, one should select target a BMI in the

lower half of the healthy

range(18.5 to 21.5) and eat enough to maintain the

corresponding weight. It seems to me that the reduced

number of calories

required to maintain a lower weight would be an

effective CR

strategy. This opinion has been dismissed as " wrong "

by people who have studied

and interpreted a lot of relevant literature.

To me, with all the mystique surrounding concepts like

" setpoint " , " usual

calories " , " normal weight " , which are often used in

trying to determine " CR " ,

your mentioned approach, which I agree with

completely, seems like the most

logical, simple, sane, rational and intelligent

approach to defining true " CR "

in our worlds.

I would be interested in what literature defines this

as " wrong " , especially in

humans. As most all the data i see in humans, agrees

with this.

Regards

Jeff

[Guest guest]

I really like this approach. It is easy to target using the

Mifflin-St. Jeor equations. And it's essentially what I am doing

already

Diane

>

> I would like to re post my Message #17834 From Mar 4,

> 2005 on this topic.

>

> My comments still apply.

> Thanks

> Jeff

>

> Message #17834 From Mar 4, 2005

>

> RE: [ ] Why do plateaus happen?

>

> >>In my opinion, one should select target a BMI in the

> lower half of the healthy

> range(18.5 to 21.5) and eat enough to maintain the

> corresponding weight. It seems to me that the reduced

> number of calories

> required to maintain a lower weight would be an

> effective CR

> strategy. This opinion has been dismissed as " wrong "

> by people who have studied

> and interpreted a lot of relevant literature.

>

> To me, with all the mystique surrounding concepts like

> " setpoint " , " usual

> calories " , " normal weight " , which are often used in

> trying to determine " CR " ,

> your mentioned approach, which I agree with

> completely, seems like the most

> logical, simple, sane, rational and intelligent

> approach to defining true " CR "

> in our worlds.

>

> I would be interested in what literature defines this

> as " wrong " , especially in

> humans. As most all the data i see in humans, agrees

> with this.

>

> Regards

> Jeff

>

[Guest guest]

Hi Jeff:

Yes, that makes a lot of sense.

And in addition we are not stuck with BMI as the only benchmark to

look at. There are lots of others that have been discussed here. So

in the case of those for whom BMI is not a good indicator, the other

measures may provide a better overall picture.

But for most people, I think, BMI is pretty good, and 18.5 to 21.5 an

appropriate range for most people. I seem to recall that studies

have been posted here which found that people in the lower half of

the 21.5 - 24.9 BMI range were healthier than those in the upper half.

Rodney.

--- In , Jeff Novick <chefjeff40@...>

wrote:

>

> I would like to re post my Message #17834 From Mar 4,

> 2005 on this topic.

>

> My comments still apply.

> Thanks

> Jeff

>

> Message #17834 From Mar 4, 2005

>

> RE: [ ] Why do plateaus happen?

>

> >>In my opinion, one should select target a BMI in the

> lower half of the healthy

> range(18.5 to 21.5) and eat enough to maintain the

> corresponding weight. It seems to me that the reduced

> number of calories

> required to maintain a lower weight would be an

> effective CR

> strategy. This opinion has been dismissed as " wrong "

> by people who have studied

> and interpreted a lot of relevant literature.

>

> To me, with all the mystique surrounding concepts like

> " setpoint " , " usual

> calories " , " normal weight " , which are often used in

> trying to determine " CR " ,

> your mentioned approach, which I agree with

> completely, seems like the most

> logical, simple, sane, rational and intelligent

> approach to defining true " CR "

> in our worlds.

>

> I would be interested in what literature defines this

> as " wrong " , especially in

> humans. As most all the data i see in humans, agrees

> with this.

>

> Regards

> Jeff

>

[Guest guest]

Hi folks:

Ooooops. Sorry. Another correction:

Where I said below " 21.5 - 24.9 " I had meant to say " 18.5 to 24.9 " .

I am gonna have to edit these things more carefully I see.

Rodney.

> >

> > I would like to re post my Message #17834 From Mar 4,

> > 2005 on this topic.

> >

> > My comments still apply.

> > Thanks

> > Jeff

> >

> > Message #17834 From Mar 4, 2005

> >

> > RE: [ ] Why do plateaus happen?

> >

> > >>In my opinion, one should select target a BMI in the

> > lower half of the healthy

> > range(18.5 to 21.5) and eat enough to maintain the

> > corresponding weight. It seems to me that the reduced

> > number of calories

> > required to maintain a lower weight would be an

> > effective CR

> > strategy. This opinion has been dismissed as " wrong "

> > by people who have studied

> > and interpreted a lot of relevant literature.

> >

> > To me, with all the mystique surrounding concepts like

> > " setpoint " , " usual

> > calories " , " normal weight " , which are often used in

> > trying to determine " CR " ,

> > your mentioned approach, which I agree with

> > completely, seems like the most

> > logical, simple, sane, rational and intelligent

> > approach to defining true " CR "

> > in our worlds.

> >

> > I would be interested in what literature defines this

> > as " wrong " , especially in

> > humans. As most all the data i see in humans, agrees

> > with this.

> >

> > Regards

> > Jeff

> >

>

[Guest guest]

> In my opinion, one should select target a BMI in the

> lower half of the healthy

> range(18.5 to 21.5) and eat enough to maintain the

> corresponding weight. It seems to me that the reduced

> number of calories

> required to maintain a lower weight would be an

> effective CR strategy.

I agree Jeff. We know that there are many health benefits for being

lean. Looking at the bathroom scale every day and making adjustments

in the amount of food that you eat to maintain a specific weight is a

lot easier than counting calories for every meal. Of course, you also

have to concentrate on nutrition.

Although this approach is very practical, there is still a theoretical

need to determine Percent CR for humans in a reliable way to be able

to compare people with different levels of restriction and also to try

to find some correlation between human data and mouse data which is

all based on Percent CR.

Tony