Re: Metabolism and CR

[Guest guest]

According to Tony's case study #1 at the bottom of

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

CR also slows metabolism.

Diane

--- In , " two_timr " <antonio@l...>

wrote:

> Hi Group,

>

> I have always known (and maybe I am wrong on this) that metabolism

> tends to slow down when a person starves oneself. I'm not implying

> that CR is a starving diet or anything but it is close to the

> threshold of starvation.

>

> Does anyone have anything on the affects of a person's metabolism

when

> doing CR? I'm looking for studies, graphs (metabolism vs. number of

> calories), etc.

[Guest guest]

According to Tony's case study #1 at the bottom of

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

CR also slows metabolism.

Diane

--- In , " two_timr " <antonio@l...>

wrote:

> Hi Group,

>

> I have always known (and maybe I am wrong on this) that metabolism

> tends to slow down when a person starves oneself. I'm not implying

> that CR is a starving diet or anything but it is close to the

> threshold of starvation.

>

> Does anyone have anything on the affects of a person's metabolism

when

> doing CR? I'm looking for studies, graphs (metabolism vs. number of

> calories), etc.

[Guest guest]

Hi :

Well clearly anyone previously not on CR, who embarks on CR will lose

weight, and as they lose weight they will burn less calories as, for

example, the -Benedict equation implies.

Does this answer your question? Or is it more complicated than I

realize?

IOW, the -Benedict equation will tell you approximately how

caloric expenditure will vary with body weight. And there is an

equilibrium body weight, for any given individual, corresponding to

any given stable rate of caloric intake. (Keeping other variables

such as exercise, ambient temperature etc unchanged).

Rodney.

--- In , " two_timr " <antonio@l...>

wrote:

> Hi Group,

>

> I have always known (and maybe I am wrong on this) that metabolism

> tends to slow down when a person starves oneself. I'm not implying

> that CR is a starving diet or anything but it is close to the

> threshold of starvation.

>

> Does anyone have anything on the affects of a person's metabolism

when

> doing CR? I'm looking for studies, graphs (metabolism vs. number of

> calories), etc.

[Guest guest]

Hi :

Well clearly anyone previously not on CR, who embarks on CR will lose

weight, and as they lose weight they will burn less calories as, for

example, the -Benedict equation implies.

Does this answer your question? Or is it more complicated than I

realize?

IOW, the -Benedict equation will tell you approximately how

caloric expenditure will vary with body weight. And there is an

equilibrium body weight, for any given individual, corresponding to

any given stable rate of caloric intake. (Keeping other variables

such as exercise, ambient temperature etc unchanged).

Rodney.

--- In , " two_timr " <antonio@l...>

wrote:

> Hi Group,

>

> I have always known (and maybe I am wrong on this) that metabolism

> tends to slow down when a person starves oneself. I'm not implying

> that CR is a starving diet or anything but it is close to the

> threshold of starvation.

>

> Does anyone have anything on the affects of a person's metabolism

when

> doing CR? I'm looking for studies, graphs (metabolism vs. number of

> calories), etc.

[Guest guest]

Al,

But in Tony's case study that I pointed out earlier at

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

the CRONer's energy intake is substantially lower than the HB equation

would predict, yet she still had a stable weight. This implies that

metabolism is slowing. Assuming the age, sex, and height stays the

same, I thought the HB predicts lower energy expenditure due to

reduced lean body mass.

Diane

> > Hi Group,

> >

> > I have always known (and maybe I am wrong on this) that metabolism

> > tends to slow down when a person starves oneself. I'm not

implying

> > that CR is a starving diet or anything but it is close to the

> > threshold of starvation.

> >

> > Does anyone have anything on the affects of a person's metabolism

> when

> > doing CR? I'm looking for studies, graphs (metabolism vs. number

of

> > calories), etc.

[Guest guest]

Al,

But in Tony's case study that I pointed out earlier at

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

the CRONer's energy intake is substantially lower than the HB equation

would predict, yet she still had a stable weight. This implies that

metabolism is slowing. Assuming the age, sex, and height stays the

same, I thought the HB predicts lower energy expenditure due to

reduced lean body mass.

Diane

> > Hi Group,

> >

> > I have always known (and maybe I am wrong on this) that metabolism

> > tends to slow down when a person starves oneself. I'm not

implying

> > that CR is a starving diet or anything but it is close to the

> > threshold of starvation.

> >

> > Does anyone have anything on the affects of a person's metabolism

> when

> > doing CR? I'm looking for studies, graphs (metabolism vs. number

of

> > calories), etc.

[Guest guest]

Hi Diane:

It could be. But I have a couple of difficulties with that.

First, it seems pretty clear that individual body mass/caloric

expenditure relationships vary considerably around the 'mean of the

overall population' number that -Benedict (H- supposedly

comes up with. Many factors would account for the difference.

Including differing body temperatures; amount of clothing worn (which

I believe is greatly influenced by what one gets used to during

childhood); exercise amounts; ambient temperatures; intestinal

absorption efficiency; ratio of surface area to body weight (which

may be especially relevant for tall and short people); and no doubt

others. Because of all these factors, variations from the H-B

equation averages are to be expected, in many cases, to be

appreciable. So we should not be surprised by a random assortment of

data points, some above, some below, the H-B predictions.

Second, perhaps I am mistaken, but this seems to me like a circular

argument. Where did the H-B people get their data from, for low body

weight people? Not from people who eat massive amounts of food

because they would not have been slim in the first place. They got

them from people who were eating relatively few calories. So surely

then, by definition, the data H-B obtained for slim people, were from

people who were on CR, whether or not they (or H or were familiar

with the expression 'CR'?

So does it make sense to say that slim people who do not eat much and

are members of should expect to exhibit a reduced

metabolism, while slim people who do not eat much, and are similar in

every way except that they happen not to be members of

and therefore never happen to have heard of the expression CR, should

not? That does seem to me to be the implications of what you are

saying.

Do you see my point? Perhaps it is me here that is confused? If so

please say so!

Rodney.

> > > Hi Group,

> > >

> > > I have always known (and maybe I am wrong on this) that

metabolism

> > > tends to slow down when a person starves oneself. I'm not

> implying

> > > that CR is a starving diet or anything but it is close to the

> > > threshold of starvation.

> > >

> > > Does anyone have anything on the affects of a person's

metabolism

> > when

> > > doing CR? I'm looking for studies, graphs (metabolism vs.

number

> of

> > > calories), etc.

[Guest guest]

Hi Diane:

It could be. But I have a couple of difficulties with that.

First, it seems pretty clear that individual body mass/caloric

expenditure relationships vary considerably around the 'mean of the

overall population' number that -Benedict (H- supposedly

comes up with. Many factors would account for the difference.

Including differing body temperatures; amount of clothing worn (which

I believe is greatly influenced by what one gets used to during

childhood); exercise amounts; ambient temperatures; intestinal

absorption efficiency; ratio of surface area to body weight (which

may be especially relevant for tall and short people); and no doubt

others. Because of all these factors, variations from the H-B

equation averages are to be expected, in many cases, to be

appreciable. So we should not be surprised by a random assortment of

data points, some above, some below, the H-B predictions.

Second, perhaps I am mistaken, but this seems to me like a circular

argument. Where did the H-B people get their data from, for low body

weight people? Not from people who eat massive amounts of food

because they would not have been slim in the first place. They got

them from people who were eating relatively few calories. So surely

then, by definition, the data H-B obtained for slim people, were from

people who were on CR, whether or not they (or H or were familiar

with the expression 'CR'?

So does it make sense to say that slim people who do not eat much and

are members of should expect to exhibit a reduced

metabolism, while slim people who do not eat much, and are similar in

every way except that they happen not to be members of

and therefore never happen to have heard of the expression CR, should

not? That does seem to me to be the implications of what you are

saying.

Do you see my point? Perhaps it is me here that is confused? If so

please say so!

Rodney.

> > > Hi Group,

> > >

> > > I have always known (and maybe I am wrong on this) that

metabolism

> > > tends to slow down when a person starves oneself. I'm not

> implying

> > > that CR is a starving diet or anything but it is close to the

> > > threshold of starvation.

> > >

> > > Does anyone have anything on the affects of a person's

metabolism

> > when

> > > doing CR? I'm looking for studies, graphs (metabolism vs.

number

> of

> > > calories), etc.

[Guest guest]

Rodney,

I think that Diane's interpretation that CR slows metabolism (or

becomes more efficient) is correct. The case study #1 in my web page

is none other than Liza May (I did not want to identify her by name on

my web page). When I was looking at the possibility of using HB

equations as a reference for %CR, I went through the data from the CR

Society member profiles trying to test the methodology.

I was surprised that long-term CR practitioners consumed fewer

calories than predicted by the HB or Mifflin-St Jeor equations. From

communication by e-mail with other members ( Derram, Arturo

[volae]), I became convinced that the difference in the number of

calories consumed by CRonies and that predicted by the energy

equations can be used as biomarker for CR.

In a note to the CRsociety (Tue, 1 Feb 2005), I wrote:

>>>

The difference in the Basal Energy Expenditure of a CR-adjusted body

from the " normal " HB BEE can be used as an objective biomarker of

successful CRON, supplementing those listed in BT120YD p.42.

In 's case, he consumes 1425 calories per day and spends 700 on

exercise. This means that his BEE is 1425-700 = 725 calories instead

of the 1479 calculated by HB. Of course, this assumes that his body is

really in material equilibrium which can be verified because his

weight has been stable " for quite some time " . I think that the ratio

725/1479 = 0.49 could be used as a biomarker for CRON.

>>>

The fact that people get to a " plateau " in their weight while

decreasing caloric consumption is an indication that body has switched

to a slower or more efficient metabolism. This effect has also been

blamed for the ease with which weight is gained by people who " fall

off the wagon " on a diet. If your weight has stabilized with lower

calorie consumption and you then start eating " normally " , your starved

and more efficient metabolism will pile up the pounds.

The energy equations like HB or Mifflin-St Jeor are representative of

normal people fed ad libitum. This is what makes them a good

reference for estimating percentage of caloric restriction, but the

equations don't accurately represent the caloric requirements of

well-established CRONies.

Tony

============

> > > > Hi Group,

> > > >

> > > > I have always known (and maybe I am wrong on this) that

> metabolism

> > > > tends to slow down when a person starves oneself. I'm not

> > implying

> > > > that CR is a starving diet or anything but it is close to the

> > > > threshold of starvation.

> > > >

> > > > Does anyone have anything on the affects of a person's

> metabolism

> > > when

> > > > doing CR? I'm looking for studies, graphs (metabolism vs.

> number

> > of

> > > > calories), etc.

[Guest guest]

Rodney,

I think that Diane's interpretation that CR slows metabolism (or

becomes more efficient) is correct. The case study #1 in my web page

is none other than Liza May (I did not want to identify her by name on

my web page). When I was looking at the possibility of using HB

equations as a reference for %CR, I went through the data from the CR

Society member profiles trying to test the methodology.

I was surprised that long-term CR practitioners consumed fewer

calories than predicted by the HB or Mifflin-St Jeor equations. From

communication by e-mail with other members ( Derram, Arturo

[volae]), I became convinced that the difference in the number of

calories consumed by CRonies and that predicted by the energy

equations can be used as biomarker for CR.

In a note to the CRsociety (Tue, 1 Feb 2005), I wrote:

>>>

The difference in the Basal Energy Expenditure of a CR-adjusted body

from the " normal " HB BEE can be used as an objective biomarker of

successful CRON, supplementing those listed in BT120YD p.42.

In 's case, he consumes 1425 calories per day and spends 700 on

exercise. This means that his BEE is 1425-700 = 725 calories instead

of the 1479 calculated by HB. Of course, this assumes that his body is

really in material equilibrium which can be verified because his

weight has been stable " for quite some time " . I think that the ratio

725/1479 = 0.49 could be used as a biomarker for CRON.

>>>

The fact that people get to a " plateau " in their weight while

decreasing caloric consumption is an indication that body has switched

to a slower or more efficient metabolism. This effect has also been

blamed for the ease with which weight is gained by people who " fall

off the wagon " on a diet. If your weight has stabilized with lower

calorie consumption and you then start eating " normally " , your starved

and more efficient metabolism will pile up the pounds.

The energy equations like HB or Mifflin-St Jeor are representative of

normal people fed ad libitum. This is what makes them a good

reference for estimating percentage of caloric restriction, but the

equations don't accurately represent the caloric requirements of

well-established CRONies.

Tony

============

> > > > Hi Group,

> > > >

> > > > I have always known (and maybe I am wrong on this) that

> metabolism

> > > > tends to slow down when a person starves oneself. I'm not

> > implying

> > > > that CR is a starving diet or anything but it is close to the

> > > > threshold of starvation.

> > > >

> > > > Does anyone have anything on the affects of a person's

> metabolism

> > > when

> > > > doing CR? I'm looking for studies, graphs (metabolism vs.

> number

> > of

> > > > calories), etc.

[Guest guest]

Hi Tony:

Do we know how H-B arrived at their equation to account for the

caloric intake of people at lower BMIs?

If all they effectively did was extrapolate for a BMI of, say, 18

from the data they had collected on people with BMIs of, perhaps, 22

and 26, then the point you and Diane are making could well make sense.

But if their data for lower BMI individuals came from actual

measurements of people with low BMIs then it seems to me it doesn't.

Since, as I suggested, their low BMI subjects would also have been on

CR, or else they would not have had a low BMI.

Of course people on CR weigh less and so will use fewer calories for

that reason. But beyond that you appear to be saying, in effect,

that when one accounts for the number of calories used by different

tissue types, muscle, fat, brain, bone, blood ............ then

when the calculation is done for those on CR the amount of energy

used is less ***per unit of weight*** for these tissues than for

someone feeding ad lib, per unit of their higher weight.

I would have to give some thought to how I would try to go about

calculating that. And whether there are data that could be used to

demonstrate it one way or the other. If we are going to dispute the

validity of H-B - which I have never regarded as accurate for myself,

I am convinced also that I use less than H-B predicts - then perhaps

we need to find data for the energy usage per unit weight of the

different types of tissue, and calculate hypothetical caloric

expenditure using estimates of the amount of each tissue type lost as

people transition to their CR weight.

I have seen this kind of data somewhere quite some time ago. I am

not sure if I will be able to relocate it.

Another project to think about! Sigh!

Also, I think we can agree that it has been shown that mice fed 40%

fewer calories at equilibium eventually weigh 50% less than ad lib

mice. So a 200 pound ad lib mouse fed 2000 calories might instead

have weighed 100 pounds on 1200 calories.

So the ad lib mouse is consuming ten calories per pound. The

restricted mouse is consuming twelve calories per pound. I remember

you making this point yourself in the past when you have asked, " what

is CR, eating more food? " (per unit of weight implied).

So there are a number of issues here that are crying out to be

cleared up, it seems. But not tonight!

Rodney.

> >>>

> The difference in the Basal Energy Expenditure of a CR-adjusted body

> from the " normal " HB BEE can be used as an objective biomarker of

> successful CRON, supplementing those listed in BT120YD p.42.

>

> In 's case, he consumes 1425 calories per day and spends 700

on

> exercise. This means that his BEE is 1425-700 = 725 calories instead

> of the 1479 calculated by HB. Of course, this assumes that his body

is

> really in material equilibrium which can be verified because his

> weight has been stable " for quite some time " . I think that the ratio

> 725/1479 = 0.49 could be used as a biomarker for CRON.

> >>>

>

> The fact that people get to a " plateau " in their weight while

> decreasing caloric consumption is an indication that body has

switched

> to a slower or more efficient metabolism. This effect has also

been

> blamed for the ease with which weight is gained by people who " fall

> off the wagon " on a diet. If your weight has stabilized with lower

> calorie consumption and you then start eating " normally " , your

starved

> and more efficient metabolism will pile up the pounds.

>

> The energy equations like HB or Mifflin-St Jeor are representative

of

> normal people fed ad libitum. This is what makes them a good

> reference for estimating percentage of caloric restriction, but the

> equations don't accurately represent the caloric requirements of

> well-established CRONies.

>

> Tony

>

> ============

[Guest guest]

Hi Tony:

Do we know how H-B arrived at their equation to account for the

caloric intake of people at lower BMIs?

If all they effectively did was extrapolate for a BMI of, say, 18

from the data they had collected on people with BMIs of, perhaps, 22

and 26, then the point you and Diane are making could well make sense.

But if their data for lower BMI individuals came from actual

measurements of people with low BMIs then it seems to me it doesn't.

Since, as I suggested, their low BMI subjects would also have been on

CR, or else they would not have had a low BMI.

Of course people on CR weigh less and so will use fewer calories for

that reason. But beyond that you appear to be saying, in effect,

that when one accounts for the number of calories used by different

tissue types, muscle, fat, brain, bone, blood ............ then

when the calculation is done for those on CR the amount of energy

used is less ***per unit of weight*** for these tissues than for

someone feeding ad lib, per unit of their higher weight.

I would have to give some thought to how I would try to go about

calculating that. And whether there are data that could be used to

demonstrate it one way or the other. If we are going to dispute the

validity of H-B - which I have never regarded as accurate for myself,

I am convinced also that I use less than H-B predicts - then perhaps

we need to find data for the energy usage per unit weight of the

different types of tissue, and calculate hypothetical caloric

expenditure using estimates of the amount of each tissue type lost as

people transition to their CR weight.

I have seen this kind of data somewhere quite some time ago. I am

not sure if I will be able to relocate it.

Another project to think about! Sigh!

Also, I think we can agree that it has been shown that mice fed 40%

fewer calories at equilibium eventually weigh 50% less than ad lib

mice. So a 200 pound ad lib mouse fed 2000 calories might instead

have weighed 100 pounds on 1200 calories.

So the ad lib mouse is consuming ten calories per pound. The

restricted mouse is consuming twelve calories per pound. I remember

you making this point yourself in the past when you have asked, " what

is CR, eating more food? " (per unit of weight implied).

So there are a number of issues here that are crying out to be

cleared up, it seems. But not tonight!

Rodney.

> >>>

> The difference in the Basal Energy Expenditure of a CR-adjusted body

> from the " normal " HB BEE can be used as an objective biomarker of

> successful CRON, supplementing those listed in BT120YD p.42.

>

> In 's case, he consumes 1425 calories per day and spends 700

on

> exercise. This means that his BEE is 1425-700 = 725 calories instead

> of the 1479 calculated by HB. Of course, this assumes that his body

is

> really in material equilibrium which can be verified because his

> weight has been stable " for quite some time " . I think that the ratio

> 725/1479 = 0.49 could be used as a biomarker for CRON.

> >>>

>

> The fact that people get to a " plateau " in their weight while

> decreasing caloric consumption is an indication that body has

switched

> to a slower or more efficient metabolism. This effect has also

been

> blamed for the ease with which weight is gained by people who " fall

> off the wagon " on a diet. If your weight has stabilized with lower

> calorie consumption and you then start eating " normally " , your

starved

> and more efficient metabolism will pile up the pounds.

>

> The energy equations like HB or Mifflin-St Jeor are representative

of

> normal people fed ad libitum. This is what makes them a good

> reference for estimating percentage of caloric restriction, but the

> equations don't accurately represent the caloric requirements of

> well-established CRONies.

>

> Tony

>

> ============

[Guest guest]

> Hi Tony:

>

> Do we know how H-B arrived at their equation to account for the

> caloric intake of people at lower BMIs?

>

====

Rodney,

The Mifflin-St Jeor equation, which is considered somewhat more

accurate than the -Benedict equation was based on individuals

with a wide range of physical characteristics.

Tony

=====

Am J Clin Nutr. 1990 Feb;51(2):241-7.

A new predictive equation for resting energy expenditure in

healthy individuals.

Mifflin MD, St Jeor ST, Hill LA, BJ, Daugherty SA, Koh YO.

Nutrition Education and Research Program, University of Nevada

School of Medicine, Reno 89557.

A predictive equation for resting energy expenditure (REE) was

derived from data from 498 healthy subjects, including females (n =

247) and males (n = 251), aged 19-78 y (45 +/- 14 y, mean +/- SD).

Normal-weight (n = 264) and obese (n = 234) individuals were studied

and REE was measured by indirect calorimetry. Multiple-regression

analyses were employed to drive relationships between REE and weight,

height, and age for both men and women (R2 = 0.71): REE = 9.99 x

weight + 6.25 x height - 4.92 x age + 166 x sex (males, 1; females, 0)

- 161. Simplification of this formula and separation by sex did not

affect its predictive value: REE (males) = 10 x weight (kg) + 6.25 x

height (cm) - 5 x age (y) + 5; REE (females) = 10 x weight (kg) + 6.25

x height (cm) - 5 x age (y) - 161. The inclusion of relative body

weight and body-weight distribution did not significantly improve the

predictive value of these equations. The -Benedict Equations

derived in 1919 overestimated measured REE by 5% (p less than 0.01).

Fat-free mass (FFM) was the best single predictor of REE (R2 = 0.64):

REE = 19.7 x FFM + 413. Weight also was closely correlated with REE

(R2 = 0.56): REE = 15.1 x weight + 371.

PMID: 2305711

[Guest guest]

> Hi Tony:

>

> Do we know how H-B arrived at their equation to account for the

> caloric intake of people at lower BMIs?

>

====

Rodney,

The Mifflin-St Jeor equation, which is considered somewhat more

accurate than the -Benedict equation was based on individuals

with a wide range of physical characteristics.

Tony

=====

Am J Clin Nutr. 1990 Feb;51(2):241-7.

A new predictive equation for resting energy expenditure in

healthy individuals.

Mifflin MD, St Jeor ST, Hill LA, BJ, Daugherty SA, Koh YO.

Nutrition Education and Research Program, University of Nevada

School of Medicine, Reno 89557.

A predictive equation for resting energy expenditure (REE) was

derived from data from 498 healthy subjects, including females (n =

247) and males (n = 251), aged 19-78 y (45 +/- 14 y, mean +/- SD).

Normal-weight (n = 264) and obese (n = 234) individuals were studied

and REE was measured by indirect calorimetry. Multiple-regression

analyses were employed to drive relationships between REE and weight,

height, and age for both men and women (R2 = 0.71): REE = 9.99 x

weight + 6.25 x height - 4.92 x age + 166 x sex (males, 1; females, 0)

- 161. Simplification of this formula and separation by sex did not

affect its predictive value: REE (males) = 10 x weight (kg) + 6.25 x

height (cm) - 5 x age (y) + 5; REE (females) = 10 x weight (kg) + 6.25

x height (cm) - 5 x age (y) - 161. The inclusion of relative body

weight and body-weight distribution did not significantly improve the

predictive value of these equations. The -Benedict Equations

derived in 1919 overestimated measured REE by 5% (p less than 0.01).

Fat-free mass (FFM) was the best single predictor of REE (R2 = 0.64):

REE = 19.7 x FFM + 413. Weight also was closely correlated with REE

(R2 = 0.56): REE = 15.1 x weight + 371.

PMID: 2305711