JAMA Meta Analysis of Research Shows Lower Mortality Associated with Overweight and Obese Mass Body Index Categories

by Kirke on January 14, 2013

They say it’s better to get it out of your system, so I have to weigh-in on this hot-topic issue. I have read the research paper published in the Journal of the American Medical Association. The report suggests that people whose BMI ranks them as overweight or slightly obese have 6% less risk of dying than people of normal weight. I have heard and read comments by health pundits and gurus some of which were vitriolic, some measured, and some panicked, most I found misguided. The research paper was given wide exposure due to the credibility of the source journal and the lead researcher’s credentials, Katherine Flegal, PhD of the Centers for Disease Control and Prevention. The fact that the meta-analysis involved 97 studies and a sample size of 2.9 million people only adds to credulity. Some news outlets reported the news with balanced reporting. But all headlines are written to be catchy, and they stick in our memories longer than the last paragraph, where the detailed critical reviews are found. On January 1, 2013 WebMD led with “A Few Extra Pounds Linked to a Longer Life,” for example. I guess the sensational, alliterative headline brings in more hits.

I spotted the problem with this study at first glance. Body mass index (BMI), simply weight divided by height squared, is used as the primary criteria. Just because all 2.9 million subjects were measured with the same measuring stick won’t assure accurate results if the measuring stick is flawed. And a high BMI is only part of a syndrome that can lead to premature mortality. Alas, this demonstrates an intrinsic problem with scientific research. The discipline involves narrowing parameters, isolating variables to study isolated problems, and in some cases reductionism is a necessary consequence of the scientific method. In this case the issue is that just being overweight or obese alone won’t kill you. Most often it is not one symptom that will lead to your premature demise. (Maybe I should say inevitable demise; life is fatal, in most cases.) It is all the accompanying complications, or comorbidities such as diabetes, hypertension, atherosclerosis, heart disease, and cancers that often result from the lifestyle of the overweight or obese person that brings about the final round of life.

I know that it is not considered scientifically valid to present evidence consisting of data obtained from only one subject when proposing a hypothesis, but time is short and pools of available data I can access this afternoon are small, so I will use my own experience and annual physicals as the data set, a sample size of one, me. Ignoring the fact that my evidence is completely anecdotal, I am presenting more variables than the research paper under review considered. Now I don’t hold myself up as an example of a person who led a particularly healthy life. I’ve had my vices and predilections as a working chef, a career that does not necessarily lend itself to a healthy lifestyle. Regardless, I have been categorized by the BMI standards (developed by Belgian Lambert Adolphe Quetelet, approved for use in the US by the National Institute of Health (NIH) in 1985, and updated to current form in 1998) to have been overweight much of my adult life. I should point out that my classification as being overweight did not take into account my ordinary, but not completely insignificant amount of muscle mass, a common confounding problem with body mass indexing.

My personal doctor at the time of first being so categorized stressed that what I needed to worry about was my high blood pressure, high serum cholesterol, my higher than average consumption of alcohol and the resulting accumulation of visceral fat around my liver, and not my BMI. In 2010 when I was attending a Medical Nutrition Therapy class I was taught precisely that regarding the comorbidities of weight issues. You have to treat the whole person. Good health and longevity result from a myriad of lifestyle factors, genetic predispositions, quality of nutrition throughout life, and environmental factors, not just the number you see on the digital scale. In the same way that a single nutrient will not prevent a person from developing cancer, a certain body weight categorization will not guarantee a longer life or condemn you to death, unless you find yourself in the higher obesity range, a scenario I would recommend striving to avoid.

Health is not defined by weight. I suggest reading the book by Linda Bacon, PhD entitled Health at Every Size, The Surprising Truth About Your Weight. Her philosophy of health takes aim at wellness first. Her research proved that her “non-diet” program led to better overall health with sustainable outcomes and weight loss as a welcome by product of lifestyle changes. Look for her book.

If you would like a more thorough, less snarky critical review of the JAMA study including references, visit Dr. Constantine Kaniklidis’ web site forum and read his informative post.Click here

 

References:

Lombard, C. (2010, December 10). How did the BMI get developed? [Fact sheet]. Retrieved January 11, 2013, from http://www.livestrong.com/article/339523-how-did-the-bmi-get-developed/

Kaniklidis, C. (2013, January 6). The obesity paradox and the Flegal JAMA study – fact or fiction? Retrieved January 9, 2013, from http://www.nosurrenderbreastcancersupportforum.com/post/The-Obesity-Paradox-6150184

Bailik, C. (2013, January 12). A good way to measure obesity? Fat chance. Retrieved January 14, 2013, from Wall Street Journal website: http://online.wsj.com/article/SB10001424127887324581504578233950347117088.html

 

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Valerie Anderson January 16, 2013 at 11:52 pm

Kirke,
Very well written-You are just humming on this blog/website. Interesting stuff. Keep it up!

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