The Unending Quest for More Research

An interesting thing that Dr. Pretlow has noticed is how the same information is susceptible to being parsed in different and sometimes contrary ways by different authorities. Various institutions perform studies, and then experts make pronouncements based on their subjective interpretations.

In the recent past, for instance, unfortunate misunderstandings were fostered by bureaucrats, news reporters and editors when the President spoke about the obesity epidemic. Currently, two contemporary studies have added to the confusion.

In April, a report from the Duke Clinical Research Institute was published by the journal Obesity with the title “Prevalence of obesity and severe obesity in US children, 1999-2014.” The lead author was Dr. Asheley Skinner, joined by colleagues from the University of North Carolina and the Wake Forest School of Medicine.

The data they analyzed came from NHANES, the National Health and Nutritional Examination Survey, which contains decades of information on Americans. In this case, the subjects were young people age 2-19. Wiley has made available online many tables of numbers from which these researchers derived their findings.

The “Conclusions” section reads:

There is no evidence of a decline in obesity prevalence in any age group, despite substantial clinical and policy efforts targeting the issue.

Consumer Affairs reported on it with the headline, “Childhood obesity rates continue to climb, study finds,” and said:

Skinner and her team admit that there are limitations to their study, but assert that using data from the NHANES is a more accurate gauge of obesity rates than the metrics that other studies have used to show that obesity rates have declined.

Then, along came a more recent study, carried out by the Centers for Disease Control (CDC) and published in the Journal of the American Medical Association, with the mouthful of a title, “Trends in Obesity Prevalence Among Children and Adolescents in the United States, 1988-1994 Through 2013-2014.” As we mentioned yesterday, at least one of the multiple authors, Katherine M. Flegal, Ph.D., had already gone on record as being uncomfortable with previous assessments of the childhood obesity situation.

The “Conclusions” and “Relevance” section of the report says:

In this nationally representative study of US children and adolescents aged 2 to 19 years, the prevalence of obesity in 2011-2014 was 17.0% and extreme obesity was 5.8%. Between 1988-1994 and 2013-2014, the prevalence of obesity increased until 2003-2004 and then decreased in children aged 2 to 5 years, increased until 2007-2008 and then leveled off in children aged 6 to 11 years, and increased among adolescents aged 12 to 19 years.

Howell Wechsler, of Alliance for a Healthier Generation, frames it like this:

In simplest terms, here is what we learned from the latest report from the Centers for Disease Control and Prevention (CDC) on children and adolescent obesity: there has been modest progress with the youngest age group, flattening levels of obesity with kids and a slight increase in obesity rates among adolescents.

And what was the take-home for the researchers themselves? According to

The authors write that although there has been considerable speculation about the causes of the increases in obesity prevalence, data are lacking to show the causes of these trends, and there are few data to indicate reasons that these trends might accelerate, stop, or slow. “Other studies are needed to determine the reasons for these trends.”

Has anyone compared the two studies both released in the first half of 2016? Yes. For, William H. Dietz wrote the very reasonably titled, “Are we making progress in the prevention and control of childhood obesity? It all depends on how you look at it,” saying:

The difference in the interpretation of these findings depends on what year is chosen to anchor the analysis. Skinner et al. anchored their analysis with 1999–2000 data whereas Ogden et al. based theirs on 2003–2004 data. Although the two studies appear contradictory, neither analysis is incorrect — it all depends on whether you start with the 1999–2000 or 2003–2004 data. This observation suggests that reliance on NHANES data alone does not provide conclusive information on the state of the epidemic and indicates that we need to broaden our inquiry.

In other words, Dietz agrees with the authors of just about every obesity study, ever, in advising that more research is needed.

Your responses and feedback are welcome!

Source: “Prevalence of obesity and severe obesity in US children, 1999-2014,”, 04/25/16
Source: “Childhood obesity rates continue to climb, study finds,”, 04/26/16
Source: “Trends in Obesity Prevalence Among Children and Adolescents in the United States,”, 06/07/16
Source: “Trends in Obesity Prevalence Among Children and Adolescents in the United States, 1988-1994 Through 2013-2014 Published in JAMA, June 7, 2016,”, 06/08/16
Source: “Study examines trends in obesity prevalence among U.S. Adults,”, 06/08/16
Source: “Are we making progress in the prevention and control of childhood obesity? It all depends on how you look at it,”, 04/25/16
Photo credit: Kingsway School via Visual hunt/CC BY

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About Dr. Robert A. Pretlow

Dr. Robert A. Pretlow is a pediatrician and childhood obesity specialist. He has been researching and spreading awareness on the childhood obesity epidemic in the US for more than a decade.
You can contact Dr. Pretlow at:


Dr. Pretlow’s invited presentation at the American Society of Animal Science 2020 Conference
What’s Causing Obesity in Companion Animals and What Can We Do About It

Dr. Pretlow’s invited presentation at the World Obesity Federation 2019 Conference:
Food/Eating Addiction and the Displacement Mechanism

Dr. Pretlow’s Multi-Center Clinical Trial Kick-off Speech 2018:
Obesity: Tackling the Root Cause

Dr. Pretlow’s 2017 Workshop on
Treatment of Obesity Using the Addiction Model

Dr. Pretlow’s invited presentation for
TEC and UNC 2016

Dr. Pretlow’s invited presentation at the 2015 Obesity Summit in London, UK.

Dr. Pretlow’s invited keynote at the 2014 European Childhood Obesity Group Congress in Salzburg, Austria.

Dr. Pretlow’s presentation at the 2013 European Congress on Obesity in Liverpool, UK.

Dr. Pretlow’s presentation at the 2011 International Conference on Childhood Obesity in Lisbon, Portugal.

Dr. Pretlow’s presentation at the 2010 Uniting Against Childhood Obesity Conference in Houston, TX.

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