Re: Accuracy of Formulas For Determing Energy Needs

[Guest guest]

Jeff,

It is interesting that the H-B equation was found to be the most

accurate equation. Previous publications have criticized it for

overestimating BMR. PMID: 15883556 found that the Mifflin-St. Jeor

equation had the best results. Like always, measurements are always

better than predictions.

Tony

>

>

>

> Journal of the American Dietetic Association. Volume

> 107, Issue 3, Pages 393-401 (March 2007)

>

>

> This study evaluated several of these equations, and

> found that even the most accurate equation (the

> -Benedict 1.1) was inaccurate in 39% of patients

> and had an unacceptably high error.

>

[Guest guest]

Tony

I was also suprised tha they rated the H-B over the

Mifflin, which has become the standard.

I wonder if the fact that all the subjects were

hosptilized patients influenced the results

Jeff

[Guest guest]

Hi Tony/Jeff:

It seems to me neither equation makes sense at low caloric intakes.

We know mice and monkeys restricted 40% or 30% are incredibly healthy.

If we run the numbers for humans restricted by 40%, even from the (we

all agree excessively high) current average caloric intakes for males

in north America (that is, restricted 40% from ~2500 calories, which

gives 1500 calories), the corresponding weights according to either

equation are clearly unrealistic.

In both cases taking a 50-year old male, 70 " tall, eating 1500

calories (with RMR of 1091 calories using the usual 1.375 exercise

factor):

Benedict says this is consistent with a weight of ~75.9 pounds.

Mifflin-St. Jeor says ~49.8 pounds.

I did the calculations here:

http://www.webdietitian.com/wlformulas/wlformulas.jsp

I am assuming they did their programming of the equations correctly.

Rodney.

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

wrote:

>

> Tony

>

> I was also suprised tha they rated the H-B over the

> Mifflin, which has become the standard.

>

> I wonder if the fact that all the subjects were

> hosptilized patients influenced the results

>

> Jeff

>

[Guest guest]

Jeff & Rodney,

In an offlist exchange with Diane, I concluded that the fact that

patients were obese and sick contributed to higher metabolic rates,

and therefore the H-B equation provided a better fit. Here are my

comments:

>>>

I think that the clue to the results is in the type of

patients that they studied, i.e., " patients with

obesity and critical illness " .

Take a look at the Cornell H-B BEE calculator:

http://www-users.med.cornell.edu/~spon/picu/calc/beecalc.htm

You will notice in the drop-down list a variety of

" stress factors " that increase BEE. Apparently, a

sick person will consume more calories than a healthy

person when at rest. I looked at the source of the

Cornell calculator and extracted the factors that they

use (below). A severe infection requires a factor of

0.45 extra calories, which is about 45% more than

normal. Burns can double the caloric requirements!

Also, look at Welle SL, Seaton TB, RG. " Some

metabolic effects of overeating in man " , Am J Clin

Nutr. 1986 Dec;44(6):718-24. PMID: 3538842.

It turns out that BEE increases with overeating. So

if the people that they looked at were overweight and

sick, it is not a surprise that the BEEs were higher

and more in agreement with the H-B equations.

This is one study from which generalizations may not

be drawn because the patients were not normal. Each

illness can influence metabolism in different ways

that will make it difficult to obtain consistent

results.

Tony

=========

value= " 0 " None

value= " 0.1 " Infection, mild

value= " 0.25 " Infection, moderate

value= " 0.45 " Infection, severe

value= " 0.15 " Infection, peritonitis

value= " 0.1 " Operation, minor

value= " 0.15 " Operation, major

value= " 0.05 " Post-op

value= " 0.5 " Burns, < 20%

value= " 0.7 " Burns, 20-40%

value= " 1.0 " Burns, > 40%

value= " 0.3 " Trauma, multiple

value= " 0.4 " Trauma, blunt

value= " 0.2 " Trauma, skeletal

value= " 0.25 " Trauma, long-bone fracture

value= " 0.15 " Cancer

>>>

>

> Tony

>

> I was also suprised tha they rated the H-B over the

> Mifflin, which has become the standard.

>

> I wonder if the fact that all the subjects were

> hosptilized patients influenced the results

>

> Jeff

>

[Guest guest]

Yes, we do not have an "H-B" equation for CR.

HB does not consider our lower energy expenditure, and you can prove it by noticing Tony's eq gives the same %CR for all weights.

Regards.

[ ] Re: Accuracy of Formulas For Determing Energy Needs

Hi Tony/Jeff:It seems to me neither equation makes sense at low caloric intakes.We know mice and monkeys restricted 40% or 30% are incredibly healthy.If we run the numbers for humans restricted by 40%, even from the (we all agree excessively high) current average caloric intakes for males in north America (that is, restricted 40% from ~2500 calories, which gives 1500 calories), the corresponding weights according to either equation are clearly unrealistic. In both cases taking a 50-year old male, 70" tall, eating 1500 calories (with RMR of 1091 calories using the usual 1.375 exercise factor): Benedict says this is consistent with a weight of ~75.9 pounds.Mifflin-St. Jeor says ~49.8 pounds. I did the calculations here: http://www.webdietitian.com/wlformulas/wlformulas.jspI am assuming they did their programming of the equations correctly.Rodney.

..

[Guest guest]

> " jwwright " <jwwright@...> wrote:

>

> Yes, we do not have an " H-B " equation for CR.

> HB does not consider our lower energy expenditure, and you can

> prove it by noticing Tony's eq gives the same %CR for all weights.

>

Re: The %CR calculator:

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

JR,

The calculation of Percent CR for animals or humans is based on the

calories consumed by the subject compared to the calories eaten by the

control. Weight does not come into play in the equation:

%CR = 100 ×(ControlCalories - ActualCalories)/ControlCalories

As you know, mice placed on a 40% diet grow to be only half of the

size (by weight) of the mice fed ad libitum. In Messages 15517 and

14018 three years ago, I asked the question " What is CRON? - 18% more

food? " . The reason for the question was that the food consumed on a

weight basis is greater for CR animals than those fed ad libitum. This

is even reported on Masoro's classic paper " Action of food restriction

in delaying the aging process " Proc. Natl Acad. Sci. Vol 79,

pp.4239-4241, July 1982.

The %CR calculator will calculate the BMR for your current height,

weight, age, sex, and adjust it by an activity level factor. This is

displayed by the calculator, but it is not used to calculate %CR.

The Percent CR is simply based on the calories that you *actually*

eat, not on the calories calculated by the equations. The energy

equations (Mifflin-St.Jeor) are only used to estimate the calories

required by a theoretical control with all your physical

characteristics and level of activity, but with a BMI of 22 as a basis

for the Control Calories.

Tony

[Guest guest]

Hi Tony:

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.

>

> .................. As you know, mice placed on a 40% diet grow to

> be only half of the size (by weight) of the mice fed ad libitum.

[Guest guest]

Tony, I can't even guess what my control is, but I do know I operate a lower energy level than before CR.

I just think a reduction of 43% in calorie intake represents a substantial diff.

And that was not an ad lib. I had already eliminated mayo, butter on bread, oil on salads, fatty meats, deep fried foods.

I was still eating ~3200 kcals.

So if I could visualize a control it would be eating even more.

All I could really do was reduce intake until I began to lose weight, and that was 1800 kcals.

When I first looked at HB it appeared to fit me even at the reduced intake, if I guessed my base activity level correctly.

But I operated a colder body temp, feeling cold, lower energy. I think that's more than 8%. And recognize at a lower body weight, my energy savings had to be a diff number from 234#.

Just walking around, perspiring, using more energy to move the extra mass, generating less heat - all those factors mean less energy intake required.

IE, %CR has to be a function of weight. It may not be equivalent to a mouse but it is something.

Regards.

[ ] Re: Accuracy of Formulas For Determing Energy Needs

>"jwwright" <jwwright@...> wrote:>> Yes, we do not have an "H-B" equation for CR.> HB does not consider our lower energy expenditure, and you can> prove it by noticing Tony's eq gives the same %CR for all weights.> Re: The %CR calculator:http://www.scientificpsychic.com/health/cron1.htmlJR,The calculation of Percent CR for animals or humans is based on thecalories consumed by the subject compared to the calories eaten by thecontrol. Weight does not come into play in the equation:%CR = 100 ×(ControlCalories - ActualCalories)/ControlCalories

..

[Guest guest]

>

> Tony, I can't even guess what my control is, but I do know I operate

a lower energy level than before CR.

This is the point I take away from this whole discussion, as well as

the importantance of finding your own numbers.

If the H-B equation is only correct for 50% of people, that's not

enough to convince me to use it. Eating ad-lib I was 10-15lbs heavier,

but also fattier and warm! Now with a 30% or more reduction in intake,

I have stabilized but only because my metabolism must have slowed A LOT.

I'm working on finding a way to get my BMR tested, to know once and for

all how much energy my body is exerting to live.

in Albuquerque

[Guest guest]

I think you got my meaning.

Standard medical techniques just don't apply to CRers.

EG, if you get "tested", you'll be led to believe your BMx is such and such and you should eat that much, and IMO that definitely is not what I want. It's gonna tell me I "need" to eat 2300 kcals.

No way I'm going back to that.

People will be greatly surprised how few calories they need after a lifetime of 3000 kcals per day (or more).

Regards

[ ] Re: Accuracy of Formulas For Determing Energy Needs

>> Tony, I can't even guess what my control is, but I do know I operate a lower energy level than before CR. This is the point I take away from this whole discussion, as well as the importantance of finding your own numbers.If the H-B equation is only correct for 50% of people, that's not enough to convince me to use it. Eating ad-lib I was 10-15lbs heavier, but also fattier and warm! Now with a 30% or more reduction in intake, I have stabilized but only because my metabolism must have slowed A LOT.I'm working on finding a way to get my BMR tested, to know once and for all how much energy my body is exerting to live.in Albuquerque

[Guest guest]

,

The statement that the H-B equation is only correct for 50% of the

people is not quite right. The particular paper that was being

discussed included overweight and sick individuals for which the

equation did not provide a " good enough " estimate.

The equations do a fairly decent job of estimating BMR for most people

within 10% of the actual calories. When the values are " wrong " they

are still in the ballpark. Cooking with a dash of salt and a dab of

butter you still get something that is pretty close to what you would

get with 1/4 tsp of salt and 1 Tbsp of butter.

The calories that you eat to maintain a stable weight correspond to

your BMR times your activity level. You can use the H-B activity

factors to estimate your BMR using your actual calories.

Divide your daily calories by 1.375 if you are lightly active, or by

1.20 if you are sedentary. So, if you are lightly active and eat 1600

calories per day, your BMR is 1600/1.375 = 1164.

You may find the BMR calculated in this way to be substantially less

than that calculated by the H-B equations because your BMR has

decreased due to CR. I have suggested in the past that the difference

between the actual BMR and the BMR calculated by the equations can be

used as a fairly objective and quantifiable biomarker for CR. You can

get a good estimate of BMR if the calories consumed and the activity

level are accurately measured, or you can actually put on the mask to

measure respiration gases and do a more direct measurement.

Tony

> >

> > Tony, I can't even guess what my control is, but I do know I operate

> a lower energy level than before CR.

>

> This is the point I take away from this whole discussion, as well as

> the importantance of finding your own numbers.

>

> If the H-B equation is only correct for 50% of people, that's not

> enough to convince me to use it. Eating ad-lib I was 10-15lbs heavier,

> but also fattier and warm! Now with a 30% or more reduction in intake,

> I have stabilized but only because my metabolism must have slowed A LOT.

>

> I'm working on finding a way to get my BMR tested, to know once and for

> all how much energy my body is exerting to live.

>

>

> in Albuquerque

>