Optimum BMI?

A place to get your questions answered from McDougall staff dietitian, Jeff Novick, MS, RDN.

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Postby Clary » Thu Jul 24, 2008 7:04 am

JeffN wrote:...The lowest mortality rate was observed among women who weighed at least 15 percent less than the U.S. average for women of similar age and among those whose weight had been stable since early adulthood.”

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Hi Jeff--Thanks for these reports, and the previous information in this thread, too. Very interesting!

Where does one find what is considered the US average weight for women of specific age? Who provides those figures? How are they determined? --and is height considered? I am 66 (67 next month). Where do I find weight that is considered the "US average" for someone of my age?

Thanks.
"LIFE always begins again." --Edmond Bordeaux Székely
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Postby JeffN » Thu Jul 24, 2008 7:20 am

There are ongoing national health studies that collect these numbers that are done by the CDC, NIH, USDA and many are compiled at the National Center for Health Statistics'

"The National Center for Health Statistics' Web site is a rich source of information about America’s health. As the Nation’s principal health statistics agency, they compile statistical information to guide actions and policies to improve the health of our people."

http://www.cdc.gov/nchs/about.htm

Also,

The Behavioral Risk Factor Surveillance System (BRFSS) is the world’s largest, on-going telephone health survey system, tracking health conditions and risk behaviors in the United States yearly since 1984.

http://www.cdc.gov/BRFSS/


You can find specific information about height and weight here

http://www.cdc.gov/nchs/pressroom/04news/americans.htm

In regard to the study you quoted, this was done at a time when they were still using the old Metropolitan Height & Weight Tables, which are no longer used. Since then, BMI was set up as the "better" tool.

You can find some good info on the old Met Life tables here, however, I am not in anyway recommending these charts/tables but only referencing them for information

http://www.halls.md/chart/height-weight.htm

and

http://www.halls.md/

Don't get too caught up in all the numbers, as healthy is much more than just body weight and BMI.

However, if you do want "numbers" then just look at the overview of all the studies I posted in the thread and you come up with the same numbers, a BMI around 18.5-22. But that should not be the "goal" in and of themselves but the result of your following the guidelines and principles of healthy living.

Simple enough? :)

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Postby Clary » Thu Jul 24, 2008 7:50 am

JeffN wrote: Simple enough? :)

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Thanks, Jeff. Look like great resources to explore. The older I get, **and healthy!**, the more fun and rewarding it is to "compare"!

Yes, simple enough. You seem to have a gift for presenting information clearly and simply, (but can also bring out the big guns when needed! :thumbsup: )
"LIFE always begins again." --Edmond Bordeaux Székely
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Postby Suebee » Thu Jul 24, 2008 11:42 am

I read about that biosphere experiment. They had inadequate food because many of the crops failed so they ended up eating far fewer calories than originally designed. The people who had to eat this calorically reduced diet felt awful--they compensated by moving as little as possible to do their various jobs. Once out of the biosphere they ate more and gained most if not more of the weight back--probably because of lowered metabolisms. Maybe some of you like to feel weak like that, but I don't and it seems to happen whenever I try to lose weight, even slowly. I don't know what to do about that.
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CR vs Starvation

Postby JeffN » Thu Jul 24, 2008 11:54 am

Suebee wrote:I read about that biosphere experiment. They had inadequate food because many of the crops failed so they ended up eating far fewer calories than originally designed. The people who had to eat this calorically reduced diet felt awful--they compensated by moving as little as possible to do their various jobs. Once out of the biosphere they ate more and gained most if not more of the weight back--probably because of lowered metabolisms. .


Let's look at what the research says about the biosphere as is important that we move away from much of the folklore and misinformation that prevails, even if it is popular and often repeated.

The results of the bioshpere and what happened during the time are well documented (See below). The participants experienced tremendous health improvements and remained physically active.

J Gerontol A Biol Sci Med Sci. 2002 Jun;57(6):B211-24. Calorie restriction in biosphere 2: alterations in physiologic, hematologic, hormonal, and biochemical parameters in humans restricted for a 2-year period.

"With regard to the health of humans on such a diet, we observed that despite the selective restriction in calories and marked weight loss, all crew members remained in excellent health and sustained a high level of physical and mental activity throughout the entire 2 years.

However, there were several things that went wrong including being exposed to toxic gases .

Metabolism is only lowered in "relation" to their lowered body mass as they lost weight, and returned to "normal" over time, after those they choose to, returned to their regular eating habits.

Some of the particpants were pioneers in the CRON studies and not only did not gain back their original weight, or any excess weight, they dedicated their lives to continuing the studies and research on the CR.

In the current CRON studies, the men are consuming 1800 calories a day, on average, which is by no means, a starvation diet.

However, no one is recommending anyone consume inadequate calories or an inadequate diet. In fact, published studies have shown that following the principles and guidelines recommended here, subjects were able to consume as much food as they wanted, whenever they were hungry, be fully satiated, were not hungry, decreased their caloric intake, lost weight, improved all their lipid profiles and felt much better.

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Paglia DE, Walford RL.
Atypical hematological response to combined calorie restriction and chronic hypoxia in Biosphere 2 crew: a possible link to latent features of hibernation capacity.
Habitation (Elmsford). 2005;10(2):79-85.
PMID: 15742531

Lassinger BK, Kwak C, Walford RL, Jankovic J
Atypical parkinsonism and motor neuron syndrome in a Biosphere 2 participant: a possible complication of chronic hypoxia and carbon monoxide toxicity?
Mov Disord. 2004 Apr;19(4):465-9.
PMID: 15077246

Walford RL, Mock D, Verdery R, MacCallum T.
Calorie restriction in biosphere 2: alterations in physiologic, hematologic, hormonal, and biochemical parameters in humans restricted for a 2-year period.
J Gerontol A Biol Sci Med Sci. 2002 Jun;57(6):B211-24.
PMID: 12023257

Weyer C, Walford RL, Harper IT, Milner M, MacCallum T, Tataranni PA, Ravussin E.
Energy metabolism after 2 y of energy restriction: the biosphere 2 experiment.
Am J Clin Nutr. 2000 Oct;72(4):946-53.
PMID: 11010936

Walford RL, Mock D, MacCallum T, Laseter JL.
Free Full Text
Physiologic changes in humans subjected to severe, selective calorie restriction for two years in biosphere 2: health, aging, and toxicological perspectives.
Toxicol Sci. 1999 Dec;52(2 Suppl):61-5.
PMID: 10630592

Verdery RB, Walford RL.
Free Full Text
Changes in plasma lipids and lipoproteins in humans during a 2-year period of dietary restriction in Biosphere 2.
Arch Intern Med. 1998 Apr 27;158(8):900-6.
PMID: 9570177

Related Articles, Links
Walford RL, Spindler SR.
The response to calorie restriction in mammals shows features also common to hibernation: a cross-adaptation hypothesis.
J Gerontol A Biol Sci Med Sci. 1997 Jul;52(4):B179-83. Review.
PMID: 9224421

Walford RL, Bechtel R, MacCallum T, Paglia DE, Weber LJ.
"Biospheric medicine" as viewed from the two-year first closure of Biosphere 2.
Aviat Space Environ Med. 1996 Jul;67(7):609-17.
PMID: 8830939

Walford RL, Weber L, Panov S.
Abstract
Caloric restriction and aging as viewed from Biosphere 2.
Receptor. 1995 Spring;5(1):29-33. Review.
PMID: 7613481

Walford RL, Harris SB, Gunion MW.
The calorically restricted low-fat nutrient-dense diet in Biosphere 2 significantly lowers blood glucose, total leukocyte count, cholesterol, and blood pressure in humans.
Proc Natl Acad Sci U S A. 1992 Dec 1;89(23):11533-7.
PMID: 1454844 [
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Postby JeffN » Fri Aug 22, 2008 6:35 pm

A new study adds to the above list of evidence supporting that a BMI in the lower range of what is considered "healthy" may be best. In this case, it is for colon cancer, a leading cancer.

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Prospective weight change and colon cancer risk in male US health
professionals. Int J Cancer. 2008 Sep 1;123(5):1160-5.
PMID: 18546286

Epidemiological studies are remarkably consistent, especially among men, in showing that overweight and obesity [body mass index (BMI) >25] are associated with increased risk of colon cancer. However, no prospective studies address the influence of weight change in adulthood on subsequent colon cancer risk. In this study, we investigated whether weight change influences colon cancer risk utilizing prospectively collected weight data. We included 46,349 men aged 40-75 participating in the Health Professionals Follow-Up Study. Questionnaires including items on weight were completed every second year during follow-up from 1986 to 2004. Updated weight change between consecutive questionnaires during follow-up and recalled weight gain since age 21 was evaluated. All eligible men were cancer-free at baseline. Proportional hazard and restricted spline regression models were implemented. Over an 18-year period, we documented 765 cases of colon cancer. Cumulative mean BMI >22.5 was associated with significantly increased risk of colon cancer. The short-term weight change in the prior 2 to 4 years was positively and significantly associated with risk [HR = 1.14 (95% confidence interval, 1.00-1.29) for 4.54 kg (10 pounds) increment, p = 0.04 for overall trend]. Weight gain per 10 years since age 21 was associated with significantly increased risk [HR = 1.33 (1.12-1.58 ) for 4.54 kg increase per 10 years, p = 0.001]. We estimated that 29.5% of all colon cancer cases was attributable to BMI above 22.5. Our results add support that overweight and obesity are modifiable risk factors for colon cancer among men and suggest that weight has an important influence on colon cancer risk even in later life.
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Re: Optimum BMI?

Postby JeffN » Thu Dec 02, 2010 12:49 am

Body-Mass Index and Mortality among 1.46 Million White Adults

Abstract

Background
A high body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) is associated with increased mortality from cardiovascular dis- ease and certain cancers, but the precise relationship between BMI and all-cause mortality remains uncertain.

METHODS
We used Cox regression to estimate hazard ratios and 95% confidence intervals for an association between BMI and all-cause mortality, adjusting for age, study, physical activity, alcohol consumption, education, and marital status in pooled data from 19 prospective studies encompassing 1.46 million white adults, 19 to 84 years of age (median, 58).

RESULTS
The median baseline BMI was 26.2. During a median follow-up period of 10 years (range, 5 to 28), 160,087 deaths were identified. Among healthy participants who never smoked, there was a J-shaped relationship between BMI and all-cause mortal- ity. With a BMI of 22.5 to 24.9 as the reference category, hazard ratios among women were 1.47 (95 percent confidence interval [CI], 1.33 to 1.62) for a BMI of 15.0 to 18.4; 1.14 (95% CI, 1.07 to 1.22) for a BMI of 18.5 to 19.9; 1.00 (95% CI, 0.96 to 1.04) for a BMI of 20.0 to 22.4; 1.13 (95% CI, 1.09 to 1.17) for a BMI of 25.0 to 29.9; 1.44 (95% CI, 1.38 to 1.50) for a BMI of 30.0 to 34.9; 1.88 (95% CI, 1.77 to 2.00) for a BMI of 35.0 to 39.9; and 2.51 (95% CI, 2.30 to 2.73) for a BMI of 40.0 to 49.9. In general, the hazard ratios for the men were similar. Hazard ratios for a BMI below 20.0 were attenuated with longer-term follow-up.

Conclusions
In white adults, overweight and obesity (and possibly underweight) are associated with increased all-cause mortality. All-cause mortality is generally lowest with a BMI of 20.0 to 24.9.

N Engl J Med 2010;363:2211-9.
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Re: Optimum BMI?

Postby JeffN » Fri Apr 08, 2011 3:45 am

"researchers found that the risks appear to rise at body mass indexes http://men.webmd.com/news/20110406/over ... print=true

(BMIs) that are considered to be well within the normal range. The risk goes up significantly for diabetes with a BMI value of 22.3 and for cardiovascular disease above a BMI of 20.9 and above"

Overweight Teens Face Heart Risks as Adults

Study Shows Heart Risk Persists Even if a Person Loses Weight in Adulthood
By Brenda Goodman
WebMD Health News
Reviewed by Laura J. Martin, MD

April 6, 2011 -- Researchers have long known that overweight or obese kids are more likely to grow up to be heavy adults, and as overweight adults, to be more likely to develop significant health problems associated with excess body weight, including cardiovascular disease and diabetes.

Now a new study published in TheNew England Journal of Medicine has added a significant wrinkle to the problem of growing childhood girth.

The study, which followed more than 37,000 teenage boys into their 30s, shows that some of the risks associated with being an overweight teenager apparently don’t go away, even if a person loses weight later in life.

“Cardiovascular disease really is a pediatric illness. It begins in childhood,” says Peter T. Katzmarzyk, PhD, professor and associate executive director for population science at the Pennington Biomedical Research Center in Baton Rouge, La.

“Even if you change your behavior, there’s still this carryover effect that being obese or overweight as an adolescent seems to really last into adult health,” says Katzmarzyk, who was not involved in the study.

What’s more, researchers found that the risks appear to rise at body mass indexes (BMIs) that are considered to be well within the normal range. Body mass index is a measurement that relates weight to height.

“The risk goes up significantly for diabetes with a BMI value of 22.3 and for cardiovascular disease above a BMI of 20.9 and above,” says study researcher Amir Tirosh, MD, PhD. Tirosh is a fellow in the department of medicine, division of endocrinology, diabetes, and hypertension at Brigham and Women’s Hospital in Boston.

A male who stands 5 feet 6 inches and weighs 130 pounds has a BMI of 21, for example.

Teens who had BMIs higher than 25, which is the threshold for overweight, had nearly three times the risk of developing diabetes and nearly eight times the risk of having heart disease as young adults, compared to the lightest group, which averaged 5 feet 6 inches in height and weighed about 114 pounds.

Diabetes Risks May Be Changed

In contrast with what happened with heart disease in the study, researchers found that diabetes risk could be more malleable. That is, if heavy teens lost weight as adults, their risk of getting type 2 diabetes was erased.

“This is the good news, actually, of the study,” Tirosh says. “For those who would not grow up to become overweight or obese, the risk is completely reversible.”

Though the study had some limitations, including the fact that it didn’t include girls, experts say the finding was significant.

“I think it’s a very interesting and important study,” says Stephen R. Daniels, MD, PhD, chairman of the department of pediatrics at the University of Colorado Denver School of Medicine. Daniels is also pediatrician-in-chief at Children’s Hospital, Denver.

Diabetes Risks May Be Changed continued...

“One of the things we’ve been lacking is this longitudinal look at what happens in childhood and adolescence and how that plays out in adulthood in terms of the kind of outcomes they were looking at,” says Daniels, who co-authored an American Heart Association scientific statement on obesity in children but was not involved in the current research.

“Our approach to looking at BMI in children has always been a statistical approach, meaning that we took a population and assumed that it was the people at the upper end of that distribution where the problems were,” Daniels says. “We’ve never really had a good outcome-based definition of body mass index in children.”

Tracking Heart and Diabetes Risk

Researchers followed more than 37,000 Israeli young men who received health screenings at age 17 when they signed up for their country’s mandatory military service.

They continued to get checkups every three to five years until they were in their early to mid-30s.

After an average of 17 years, researchers documented nearly 1,200 cases of type 2 diabetes and 327 cases of cardiovascular disease, which was defined as having at least one coronary artery at least 50% blocked.

Looking back at the men’s BMIs when they first started the study, researchers saw a clear link between their size and their risks for both diabetes and heart disease.

Average BMIs in the study ranged from 17.4, representing an average height of 5 feet 6 inches and a weight of 114 pounds, in the lightest group, to 27.6, representing an average of 5 feet 8 inches and 185 pounds, in the heaviest group.

Those who fell into the heaviest group had about three times the risk of developing diabetes compared to the lightest teens.

For every point increase in BMI in the teens, the risk of developing type 2 diabetes as an adult increased by nearly 10% from the lowest to highest groups.

But that risk disappeared after researchers adjusted the results to reflect adult BMIs.

For heart disease risk, however, which increased 12% for every point increase in BMI, the association remained, even if the men had lost weight as adults.

“It seems to be that our body has a longer BMI memory in terms of cardiovascular diseases,” says Tirosh.

“For two 35- or 40-year-old men who have a normal BMI as adults, let’s say BMI of 22 or 23, one could have as much as a sevenfold higher risk for cardiovascular disease, simply because he used to have a higher BMI as a teenager,” Tirosh tells WebMD.

Experts say the message of the study to parents and teens should be clear.

“It’s never too early to start being healthy,” says Katzmarzyk. “Don’t wait until you’re 50 or 60 worrying about a heart attack. You really need to be concerned early on.”
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Re: Optimum BMI?

Postby jamietwo » Tue May 03, 2011 8:22 am

Hi Jeff, if you addressed this already, I can't find it!

I used the CDC's BMI calculator for children. If I input my VERY active (and intelligent, I might add :)) child's height and weight as of today, there are warning bells that he is underweight at 14.4 BMI (2nd percentile). However if I move his age back a year, but use the same height and weight as today, it tells me he is at a normal weight at 14.5 BMI (5th percentile). Why would this be a healthy weight for his height at (for example) 10 years old but not 11 years old?

I appreciated your recent post reiterating that 1-2 oz of nuts per day is the maximum acceptable for children (for some reason I thought kids could have more). Does a low BMI change that recommendation?

Thanks!
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Re: Optimum BMI?

Postby JeffN » Tue May 03, 2011 8:35 am

jamietwo wrote:Hi Jeff, if you addressed this already, I can't find it!

I used the CDC's BMI calculator for children. If I input my VERY active (and intelligent, I might add :)) child's height and weight as of today, there are warning bells that he is underweight at 14.4 BMI (2nd percentile). However if I move his age back a year, but use the same height and weight as today, it tells me he is at a normal weight at 14.5 BMI (5th percentile). Why would this be a healthy weight for his height at (for example) 10 years old but not 11 years old?


It would be hard for me to say without knowing the height and weight you are using for these equations

jamietwo wrote:I appreciated your recent post reiterating that 1-2 oz of nuts per day is the maximum acceptable for children (for some reason I thought kids could have more). Does a low BMI change that recommendation? Thanks!


My comments, as all comments in this forum, are general comments and not directed at any individual and their own individual situation. There is always variance in how these are applied to people and there are many variables that would need to be considered when making such decisions.

High fat plant foods are not necessary nor required so children can grow up fine and healthy without them. And, children can include more than what I stated and also still be healthy. I couldn't address your specific situation without you and your child being my patients.

However, Dr McDougall has written an great article on gaining weight, and in addition there are several threads here on the topic.

http://www.nealhendrickson.com/mcdougal ... weight.htm

So, it is important to remember there are general recommendations and individual specific recommendations. However, in this forum, and in any anonymous public forum, the best we can do is general recommendations.

I hope that helps!

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Re: Optimum BMI?

Postby jamietwo » Tue May 03, 2011 9:28 am

I understand. Let me rephrase my question. :) If a child is growing, active and healthy, why the emphasis on appropriate weight for "age" vs height? In our experience, he always grows "up" before he grows "out", (he's just over 5 feet tall at 11 years old).

I've read Dr. McDougall's newsletter multiple times - that's probably where I got the idea that my child could eat more nuts, etc. and translated that (over time) to include all kids.

Thanks for your input!
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Re: Optimum BMI?

Postby JeffN » Tue May 03, 2011 9:33 am

jamietwo wrote:I understand. Let me rephrase my question. :) If a child is growing, active and healthy, why the emphasis on appropriate weight for "age" vs height?


It is a system that is used to try and establish a norm and catch those who may be above or below it. However, like any system, it may have value, though it is not perfect.

My daughter never fit on the scale and I don't think I ever did either. But, I am come from a family where I don't think anyone fit the scale either, regardless of their diet. So, there are many individual issues to be considered and not just the chart.

The chart is used to help "screen" in identifying those who may be at risk. However, that diagnosis of whether or not there is an actual risk can only be made based on an evaluation of the individual and not based on the screening tool.

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Re: Optimum BMI?

Postby jamietwo » Tue May 03, 2011 9:39 am

Thanks Jeff!
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Re: Optimum BMI?

Postby Summer » Tue Feb 28, 2012 6:35 pm

JeffN wrote:Teens who had BMIs higher than 25, which is the threshold for overweight, had nearly three times the risk of developing diabetes and nearly eight times the risk of having heart disease as young adults, compared to the lightest group, which averaged 5 feet 6 inches in height and weighed about 114 pounds.


Jeff, do you know if all other factors besides bmi were excluded here? I'm wondering if a teen has a BMI around 25 would they share the same health risks regardless of waist/hip ratio, physical activity, and diet?
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Re: Optimum BMI?

Postby JeffN » Tue Feb 28, 2012 7:27 pm

BMI is only one risk factor so of course, other issues will always matter. We have to also remember that these are only risk factors, and they are obtained by studying populations so do not always apply directly to any one individual. However, my comments in this thread in relation to BMI and adults, still holds true for a teenager.

From the CDC

For Children

"BMI is used as a screening tool to identify possible weight problems for children. CDC and the American Academy of Pediatrics (AAP) recommend the use of BMI to screen for overweight and obesity in children beginning at 2 years old.

For children, BMI is used to screen for obesity, overweight, healthy weight, or underweight. However, BMI is not a diagnostic tool. For example, a child may have a high BMI for age and sex, but to determine if excess fat is a problem, a health care provider would need to perform further assessments. These assessments might include skinfold thickness measurements, evaluations of diet, physical activity, family history, and other appropriate health screenings."


For Adults.

Why is BMI used to measure overweight and obesity?

BMI can be used for population assessment of overweight and obesity. Because calculation requires only height and weight, it is inexpensive and easy to use for clinicians and for the general public. BMI can be used as a screening tool for body fatness but is not diagnostic.


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