Re: Something Paradoxical Here?

[Guest guest]

Hi folks:

Further to this earlier post of mine (below). Doing the

same 'reverse' calculation, the -Benedict equation says my

weight would drop to 116.2 pounds if I maintained a daily intake of

1800 calories.

I must be missing something here. Or else /Benedict is totally

out to lunch. So far out to lunch that it is a bit scary.

Has anyone else checked what would happen to their weight according

to -Benedict if they were to maintain a daily caloric intake of

1800? http://www.exrx.net/Calculators/CalRequire.html And do you

get numbers for your predicted weight anywhere near as ridiculous as

I seem to be getting? Or, if you actually have been consuming 1800

calories a day for a while, is your weight anywhere remotely close to

that predicted for you by -Benedict?

[i am beginning to wonder if I am making some very dumb mistake in my

calculations. But right now it seems to me that what I have been

told by a WeightWatchers franchisee (posted here a few months back)

makes a lot more sense than -Benedict.]

Rodney.

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

wrote:

> Hi folks:

>

> Something not quite right about this. Anyone got the explanation?

>

> I used the 'caloric requirement' calculator at .................

> www.exrx.net/calculators/calrequire ........ to calculate my daily

> caloric requirement (2279 calories) at my set point - which I think

I

> do know fairly accurately, my early 20s endurance training fit

weight.

>

> Then I calculated what 25% and 30% restriction would do to that

> number (reduces it to 1600 to 1700 calories per day, approximately).

>

> THEN ....... I used the same calculator in reverse ..........

that

> is, I used it to check what body weight (according to the

calculator,

> that is based on the -Benedict equation) those 1600 to 1700

> calories would support on a sustained basis. I.E. I used it to

> answer the question " given my height, age, etc., for what body

weight

> is the 1600 to 1700 calories the 'caloric requirement' " ?

>

> The answer is quite sobering. My set point is ~170 pounds.

> According to -Benedict 1655 calories would maintain a weight

of

> 100 pounds.

>

> As usual, when my weight recently dropped below 168 I started to

> look 'gaunt'. Someone has already noted my now-gaunt appearance.

>

> Clearly it would be ridiculous to drop to 100 pounds. (Indeed it

may

> be ridiculous to drop to even 150 pounds). My BF% at 100 pounds

> would be minus 26%.

>

> Not the first time the data appear to be internally inconsistent.

>

> Rodney.

[Guest guest]

Hi folks:

Thanks to everyone who responded to my 'Paradox' post.

As a result I have suddenly come to realize the key issue about the

differences between -Benedict and Katch-McArdle - and the

differences are profound.

As Jw noted, the latter is a function of only lean body mass (plus a

constant term). Take the example of someone who measures their BMR

using Katch-McArdle while doing a good job on CR - i.e. while

maintaining their non-adipose tissues like bone mass, muscles and

brain. Suppose they lose 30 pounds of body weight ONLY IN THE FORM

OF FAT. Using Katch-McArdle they will still have the same identical

BMR after they have lost the weight, as they had calculated using

Katch-McArdle before the weight loss, because their LBM has not

changed. And since adipose tissue, as I understand it, is not

metabolically active, when you lose 30 pounds of it your BMR SHOULD

be unchanged.

But in stark contrast, using the -Benedict equation, in which

simple total weight is a major variable in the calculation, the

number you come up with will be a lot less at lower weights, even

though you have probabably only lost metabolically inactive (fat)

tissue. It was more than 400 calories less in the example I

calculated for myself.

Certainly carrying less weight around will consume fewer calories.

But that is in the activity part of the calculation. Not the BMR

part.

CONCLUSION: I am beginning to think that the -Benedict

equation produces nonsense results if used for people much above or

below 'average' weights. (Who knows, perhaps at average weights too?)

Rodney.

>

> Hi folks:

>

> Further to this earlier post of mine (below). Doing the

> same 'reverse' calculation, the -Benedict equation says

my

> weight would drop to 116.2 pounds if I maintained a daily

intake of

> 1800 calories.

>

> I must be missing something here. Or else /Benedict is

totally

> out to lunch. So far out to lunch that it is a bit scary.

>

> Has anyone else checked what would happen to their weight

according

> to -Benedict if they were to maintain a daily caloric

intake of

> 1800? http://www.exrx.net/Calculators/CalRequire.html And do

you

> get numbers for your predicted weight anywhere near as

ridiculous as

> I seem to be getting? Or, if you actually have been consuming

1800

> calories a day for a while, is your weight anywhere remotely

close to

> that predicted for you by -Benedict?

>

> [i am beginning to wonder if I am making some very dumb mistake

in my

> calculations. But right now it seems to me that what I have

been

> told by a WeightWatchers franchisee (posted here a few months

back)

> makes a lot more sense than -Benedict.]

>

> Rodney.

[Guest guest]

Hi folks:

More problems with calculating BMR: I have already concluded -

Benedict makes no sense. Now here are some thoughts about Katch-

McArdle.

Logically, **if** you accept Katch-McArdle, then it follows that CR

means loss of lean body mass.

Think about it. Taking me as an example. Suppose my weight starts

out stable eating 2200 calories at a set point around 170 lbs. Then,

when I first reduce caloric intake I lose weight through loss of

fat. So my BF% will drop from its original ~21%.

When I eventually decide to stabilize my weight and increase my

calorie consumption to the level necessary to do so, Katch-McArdle

says it will be at the same 2200 calories that will be necessary -

since in the Katch-McArdle equation the only variable is lean body

mass.

THE ONLY WAY I CAN REDUCE MY CALORIE CONSUMPTION ON A LONG TERM

BASIS, ACCORDING TO THEIR EQUATION, IS TO REDUCE LEAN BODY MASS.

So it follows from their equation that, after the initial loss of

fat, if I want to reduce calorie consumption by 25% or 30% or 35%

from my baseline in the long term, then I have to lose 25% or 30% or

35% of my lean body mass.

So, of the lean body mass I possessed at the outset, which should I

feel enthusiastic about losing? Presumably not bone or brain (!). I

am not too enthusiastic about losing too much muscle either - one

does need to be healthily ambulatory. Heart muscle? Liver, with its

stores of nutrients? Kidneys with their garbage-truck function?

Skin? Hair? (!!!) Any suggestions?

Of course Warren already raised this issue here a month or so ago.

Perhaps he would like to weigh in and straighten me out.

The alternative, of course, is to consign Katch-McArdle to the ash

can too.

Rodney.

--- In , " jwwright " <jwwright@e...>

wrote:

> I just plotted the KM (15% body fat), and HB alongside the A-61 MN

data and they come closely together at about 175#, which just happens

to be where I am, more or less. I guess that's why I think the HB

works. The A-61 data looks like it would fit better to the CR low BF

person. But the diff (1350-1550) at 125# is only 13%, probably within

the noise for BMR calculations.

>

> Regards.

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

> From: Rodney

>

> Sent: Thursday, March 18, 2004 7:28 PM

> Subject: [ ] Re: Something Paradoxical Here?

>

>

> Hi folks:

>

> Thanks to everyone who responded to my 'Paradox' post.

>

> As a result I have suddenly come to realize the key issue about

the

> differences between -Benedict and Katch-McArdle - and the

> differences are profound.

>

> As Jw noted, the latter is a function of only lean body mass

(plus a

> constant term). Take the example of someone who measures their

BMR

> using Katch-McArdle while doing a good job on CR - i.e. while

> maintaining their non-adipose tissues like bone mass, muscles and

> brain. Suppose they lose 30 pounds of body weight ONLY IN THE

FORM

> OF FAT. Using Katch-McArdle they will still have the same

identical

> BMR after they have lost the weight, as they had calculated using

> Katch-McArdle before the weight loss, because their LBM has not

> changed. And since adipose tissue, as I understand it, is not

> metabolically active, when you lose 30 pounds of it your BMR

SHOULD

> be unchanged.

>

> But in stark contrast, using the -Benedict equation, in

which

> simple total weight is a major variable in the calculation, the

> number you come up with will be a lot less at lower weights, even

> though you have probabably only lost metabolically inactive (fat)

> tissue. It was more than 400 calories less in the example I

> calculated for myself.

>

> Certainly carrying less weight around will consume fewer

calories.

> But that is in the activity part of the calculation. Not the BMR

> part.

>

> CONCLUSION: I am beginning to think that the -Benedict

> equation produces nonsense results if used for people much above

or

> below 'average' weights. (Who knows, perhaps at average weights

too?)

>

> Rodney.

[Guest guest]

Hi Jw:

Thanks. That does make sense.

But if someone's objective is to reduce calories eventually by 25%

under CR, are they really expecting to see a 25% reduction in lean

body mass? (as Katch-McArdle suggests). That seems like a lot.

I also now realize that one cannot calculate future BF% on the basis

that lost weight will be all fat. I think it was JR who pointed this

out to me some time ago. But it didn't sink in at the time.

Rodney.

--- In , " jwwright " <jwwright@e...>

wrote:

> I recall studies that show that weight loss includes lean body

mass, fat, and bone mass. Logically as you get heavier the bones have

to be stronger, the muscles bigger to carry the weight. So in decline

the body adjusts those downward. Saving lean muscle is hard to do.

> And yes, I believe that heart will reduce in size also. We already

know that an enlarged heart will reduce in size. LARGE weight losses

must be over long periods to be safe, IMO. There is a " romantic " idea

the body would " naturally " conserve organ tissue, but I don't recall

a single study that says that, and we've discussed it before at

length in the CR groups.

>

> Regards.

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

> From: Rodney

>

> Sent: Friday, March 19, 2004 7:08 AM

> Subject: [ ] Re: Something Paradoxical Here?

>

>

> Hi folks:

>

> More problems with calculating BMR: I have already concluded

-

> Benedict makes no sense. Now here are some thoughts about Katch-

> McArdle.

>

> Logically, **if** you accept Katch-McArdle, then it follows that

CR

> means loss of lean body mass.

>

> Think about it. Taking me as an example. Suppose my weight

starts

> out stable eating 2200 calories at a set point around 170 lbs.

Then,

> when I first reduce caloric intake I lose weight through loss of

> fat. So my BF% will drop from its original ~21%.

>

> When I eventually decide to stabilize my weight and increase my

> calorie consumption to the level necessary to do so, Katch-

McArdle

> says it will be at the same 2200 calories that will be necessary -

> since in the Katch-McArdle equation the only variable is lean

body

> mass.

>

> THE ONLY WAY I CAN REDUCE MY CALORIE CONSUMPTION ON A LONG TERM

> BASIS, ACCORDING TO THEIR EQUATION, IS TO REDUCE LEAN BODY MASS.

>

> So it follows from their equation that, after the initial loss of

> fat, if I want to reduce calorie consumption by 25% or 30% or 35%

> from my baseline in the long term, then I have to lose 25% or 30%

or

> 35% of my lean body mass.

>

> So, of the lean body mass I possessed at the outset, which should

I

> feel enthusiastic about losing? Presumably not bone or brain

(!). I

> am not too enthusiastic about losing too much muscle either - one

> does need to be healthily ambulatory. Heart muscle? Liver, with

its

> stores of nutrients? Kidneys with their garbage-truck function?

> Skin? Hair? (!!!) Any suggestions?

>

> Of course Warren already raised this issue here a month or so

ago.

> Perhaps he would like to weigh in and straighten me out.

>

> The alternative, of course, is to consign Katch-McArdle to the

ash

> can too.

>

> Rodney.