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In presenting the Science of HAESSM we will review, dissect, and discuss
recent and/or pivotal research and scientific claims. Some studies
examined aim to document the risks of excess weight, while others
suggest paradoxes or direct evidence to support a Health At Every SizeSM
approach. Paul Ernsberger PhD
, who serves as Research Chair for ASDAH, will provide primary
analysis, with input from a variety of other experts from the
scientific and research arena. If you have any input and/or questions,
please contact our Research Committee.
HAESSM SCIENCE Q & A
Aren’t people who are too fat or too thin unhealthy?
The World Health Organization defines health as "... a state of
complete physical, mental, and social well-being and not merely the
absence of disease or infirmity."1
HAESSM affirms that there are many factors to consider when evaluating
the connections between weight and health. Fitness, activity, nutrient
intake, weight cycling or socioeconomic status as well as emotional
support systems and social interactions are all relevant to someone’s
quality of life, health, and wellness status.
Shouldn’t we do something about the obesity epidemic before it bankrupts our medical
system and people die prematurely
from diseases related to obesity?
You can’t have it both ways. If obesity causes early death, a large
segment of the population won’t live long enough to bankrupt the
medical system, since more people are obese. The reality is, while
weights have increased over the past four decades, mortality rates have
decreased. 2 Except at statistical extremes, the amount of fat on a body is a weak indicator of life expectancy.
Moreover, some studies suggest that people defined as “overweight” live longer than thinner people,3,4
while numerous studies have shown that so called ‘weight-related’
health problems can be treated effectively with lifestyle
interventions, without significant weight loss and in individuals who
remain markedly ‘obese’ by traditional medical standards.”5
What do I know when I know my BMI (Body Mass Index)?
You know the ratio of your weight to height. And that is all. While it
has become the norm to use BMI as a health measuring tool, it cannot
define or predict one’s health or wellness. The tool is used primarily
because it is easy and inexpensive. In order to speak to many of the
issues that surround health and weight, ASDAH references the BMI index
so our comparisons will be “apples to apples.” However, we believe a
combination of medical and/or psychological tests would better assess
one’s level of health and wellness.
What is a “normal” weight?
HAESSM promotes all aspects of health and well-being for people of all
sizes. In particular, it advocates eating in a manner that balances
individual nutritional needs with hunger, satiety, appetite, and
pleasure. HAESSM also supports individually appropriate, enjoyable, life
enhancing physical activity rather than exercise for the purpose of
weight loss.6
A “normal weight” is the weight at which a person’s body settles as
s/he moves towards a more fulfilling, meaningful lifestyle that
includes being physically active and consuming nutritious foods. Not
all people are currently at their most “healthy weight.” Movement
towards a more balanced life will facilitate the achievement of a
“healthy weight.” 3,4
Shouldn’t we be looking for a cure for obesity rather than promoting size-acceptance?
In order to “cure” a condition, the condition must be defined as a
disease. If we say obesity is a disease then we must say on some level
body fat is pathological. But there is no evidence that adipose tissue
is harmful to our health. For most people labeled “obese”, their
fatness is not a disorder. 7
What should we do about childhood obesity?
All children should be taught the importance of good nutrition and
physical activity. When we focus on only the “overweight” children we
do two things: (1) stigmatize and single out the larger kids as
different/wrong/bad, and (2) leave the smaller children without the
knowledge of how to best take care of themselves.
All children, large and small, should be taught how to best take care
of themselves, that all people come in different shapes and sizes, and
that no one particular shape or size is the best one. If we do that,
then we will help our children to be healthy. Our focus should be on
creating “healthy” kids, not “skinny” kids.
What about the constant influx of “experts” reporting on the dangers of the obesity epidemic?
If our scientific/medical community has already decided obesity is a
problem, they will only interpret research to back up that claim. There
are many examples of studies that refute this prevailing point of view,
yet their data are not spread in the mainstream or medical media. For
instance, the risk of death declines with increasing BMI among the
elderly, up to levels considered severely obese. 8-11
It is acceptable--necessary, in fact-- for science to explore the
differences between different body types; i.e., how they function
differently, what their different needs are. But once value is placed
on those differences, it becomes discriminatory, and that is what is
unacceptable.
References
1 Preamble, Constitution of the World Health Organization, 1948
2 National Center For Health Statistics, Social Security Administration, Census Bureau
3 Durazo-Arvizu, R., et al., Mortality and optimal body mass index in a sample of the US population.
American Journal of Epidemiology, 1998. 147: p. 739-749.
4 Flegal, K.M., et al., Excess deaths associated with underweight, overweight, and obesity.
Journal of the American Medical Association, 2005. 293(15): p. 1861-7.
5 charts Adams et al, NEJM 355:763-778, 2006, tables 2 and 3
6 Journal of Nutrition Education and Behavior Volume 37 Number 4 July • August 2005, "The
National Weight Control Registry: A Critique” JOANNE IKEDA, MA, RD1; NANCY K. AMY,
PHD1; PAUL ERNSBERGER, PHD2 ; GLENN A. GAESSER, PHD3; FRANCIE M. BERG, MS4;
CLAUDIA A. CLARK, PHD5; ELLEN S. PARHAM, PHD, RD, LD, LCPC6; PAULA PETERS, PHD
7 Oliver, JE. (2006). Fat Politics.
8 Breeze E, Clarke R, Shipley MJ, Marmot MG & Fletcher AE. Cause-specific mortality in old age in
relation to body mass index in middle age and in old age: follow-up of the Whitehall cohort of male
civil servants. Int J Epidemiol. 2006;35:169-178.
9 Inoue K, Shono T, Toyokawa S & Kawakami M. Body mass index as a predictor of mortality in
community-dwelling seniors. Aging Clin Exp Res. 2006;18:205-210.
10 Alibhai SM, Greenwood C & Payette H. An approach to the management of unintentional weight
loss in elderly people. CMAJ. 2005;172:773-780.
11 Janssen I, Katzmarzyk PT & Ross R. Body mass index is inversely related to mortality in older
people after adjustment for waist circumference. J Am Geriatr Soc. 2005;53:2112-2118.
Scientific Research 101
Paul Ernsberger, PhD
The popular press is filled with reports of scientific studies claiming
to prove that obesity is a major risk factor for disease and death. As
we know, there are many more articles showing little or no risk from
obesity, but these are never picked up by the media. Also, many of the
articles making the most extreme claims are either misrepresenting the
actual data, or relying on selective or incomplete reporting of the
total picture. As a first step toward deconstructing these reports, we
need to understand the different kinds of research studies and their
relative validity.
There are four main types of medical trials on patients. The controlled clinical trial is
the gold standard. A group of subjects is divided in half. The
experimental treatment group receives the proposed treatment for the
disease or condition, and the control group receives either no
treatment, or a placebo, or a currently accepted standard treatment.
This last type of controlled clinical study is impossible in the case
of obesity and weight loss research because there would have to be a
standard treatment with long-term effectiveness, and there is no such
treatment.
So instead of controlled clinical trials, researchers trying to
determine the health effects of different body weights or weight
changes must rely on animal studies and epidemiological studies, which
look at populations. The best population research is the prospective study,
in which a large group of people is monitored for many years. Weight is
measured at the outset, and health outcomes are recorded over time.
Examples of prospective studies are the Framingham Study, the Nurses
Health Study, and the Norwegian Study.
Retrospective studies are in third place on the reliability
scale. Researchers start with a group of people with a particular
disease or condition, and match them up with a group of controls who do
not have the disease. They then compare the medical history of the two
groups to try to determine risk factors and causes for the disease. One
problem with this kind of research is that medical histories, at least
in countries without government-run health care, must often be
self-reported, allowing errors of recall to skew the results.
The cross-sectional survey is the weakest and least
reliable type of medical study. In this type, groups of people are
surveyed, and the number of diagnoses reported by people of different
body weights is recorded. These are the easiest to do, since they
require only a questionnaire or a single medical exam. Because of their
simplicity, cross-sectional surveys are extremely common. A large
percentage of the studies reported in the popular press follow this
pattern. The problems with them are many, including failure to ask
important questions (such as social status or family history), ignoring
long-term results, and diagnostic bias. For example, doctors may look
harder for signs of a disease in patients they “expect” to have it. Fat
patients are tested for diabetes more often than thin ones. Men are
more likely than women to be screened for heart disease. Diagnostic
bias results in underreporting of heart disease in women, and of
diabetes in thin people.
Well-done research requires many steps, and must follow strict
guidelines to be considered reliable. If the data show a correlation
between a factor (A) and a result (B), this does not mean that A causes
B. Identifying a correlation is not the same as proving causation. Responsible medical researchers then take at least two more important steps.
First, they come up with as many possible biological mechanisms to explain how A could cause B. And second, they try to list all possible confounding factors that could explain the results in ways other than the hypothesis that A causes B.
It is important for readers of the popular media to look critically at
research, especially in the areas of obesity and weight loss. Did the
researchers prove causation or just suggest a correlation? Did they
think of other possible explanations for their results? And one other
question that media watchers should always consider: Was this research
funded by an entity that would profit from one particular result over
another?
Changing Definitions
Paul Ernsberger, PhD
In 1997 and 1998, the powers that be changed the levels of what
constituted a diseased state in several major categories: diabetes,
hypertension, high cholesterol, and being “overweight.”
DIABETES
Under the old definition, a fasting blood test that showed a glucose
level of 140 (mg per dl) was necessary for a diagnosis of diabetes. But
in 1997, the American Diabetes Association and the WHO Expert Committee
on the Diagnosis and Classification of Diabetes Mellitus lowered that
level to 126 mg/dl. Where 11.7 million people had been defined as
diabetic under the old definition, this change resulted in a fourteen
percent increase in the number of people with diabetes. One million,
seven hundred thousand people got diabetes overnight.
A new disease category was invented when impaired fasting glucose or
impaired glucose tolerance were renamed “pre-diabetes.” Prediabetes was
defined as having a fasting blood glucose level between 110 and 126
mg/dl. In 2003, the blood glucose level that defined the condition was
lowered to 100 mg/dl, which used to be considered normal. Although the
fine print admits that not all those with prediabetes will develop
diabetes, and that many with impaired fasting glucose actually have
normal blood glucose most of the time, the use of the “pre” strongly
suggests that the condition is a “pre” cursor to the actual disease.
The definition of diabetes has evolved over time. For most of history,
diabetes was diagnosed when sugar was present in the urine. Ancient and
medieval physicians made their diagnosis by tasting their patients’
urine. Thankfully, these days are past. Testing for urine sugar is
still done as part of a routine urinalysis, and diabetes is still
diagnosed this way. Blood sugar has to reach 300 mg/dl or higher before
significant amounts spill out of the blood and into the urine (an
exception would be if kidney disease were present). In a normal person,
blood sugar never gets this high, even after a meal. The development of
reliable chemical tests for blood sugar after World War II allowed more
sensitive tests. It became common to carry out glucose tolerance tests,
where blood samples would be taken before and after the patient drank
glucose syrup. This is still done to test for gestational diabetes
during pregnancy, but testing fasting blood sugar has been found to be
just as reliable.
How dangerous is it to have mild diabetes (fasting blood sugar of 126
to 140)? It’s not clear. A massive study called The Pooling Project put
together data from many studies, including Framingham and Tecumseh, and
found that mild elevations of blood sugar did not increase the risk of
heart attacks.1
However, the argument was made that many people with mild diabetes go
on to develop full blown diabetes, and on that basis the guidelines
were changed. The evidence that “prediabetes” is harmful is very
tenuous, and again the main argument is that people with prediabetes
should be watched closely.
HYPERTENSION
The old definition of hypertension (high blood pressure) was 160 over
100 (mm Hg, systolic over diastolic). That was changed in 1997 by the
US Joint National Committee on Prevention, Detection, Evaluation, and
Treatment of High Blood Pressure. The new definition was 140/90, and as
a result, thirteen and a half million people, or an additional 35%,
were added to the roughly thirty-nine million that had hypertension.
Here too a new disease category was invented: those with blood pressure
from 120/80 to 130/89, or forty-five million people, were defined as
“prehypertensive.”
How dangerous is mild hypertension? The evidence for harm is fairly
strong, because the risk of stroke especially but also heart failure
and heart attack rises linearly as blood pressure rises, all the way
down to a level of around 110/75. There are also randomized clinical
trials showing that treating hypertension to a target level of 140/90
saves lives. There is some evidence that people with prehypertension
are at increased risk, but the benefit of drug treatment is not clear
for this group.
CHOLESTEROL
The old definition of high cholesterol was 240 mg/dl total cholesterol.
The US Air Force/Texas Coronary Atherosclerosis Prevention Study of
1998 resulted in lowering the acceptable level to 200 mg/dl. This was
by far the greatest increase in those defined as in need of treatment.
Whereas before, forty-nine and a half million people had cholesterol
levels that required medical intervention, this change in definition
resulted in an 86% increase in those defined as having high
cholesterol. Forty-two and a half million people were added to the
ranks of those with hypercholesterolemia.
How dangerous is mild hypercholesterolemia? The evidence is quite
strong, because the risk of heart attack rises very steeply with rising
cholesterol levels above a level of 180 or so. There are now randomized
clinical trials showing that treatment with statins and other
cholesterol lowering drugs to a target of 200 mg/dl saves lives. Data
are starting to accumulate that even more aggressive treatment with
statins can save lives, so look for target levels to drop again
–perhaps to 180 –in the next few years.
“OVERWEIGHT”
It was the National Heart, Lung, and Blood Institute (part of the
National Institutes of Health) that changed the definition of
overweight and obesity. Before the change, those with a BMI (kg/m2) of
27 or more were considered “overweight.” That was changed to 25 in
1998, and an additional 30.5 million people in the US became overweight
with the stroke of a pen. This represented a 43% increase.
How dangerous is “overweight”? Most studies agree that so-called
“overweight” is actually beneficial to longevity and that relative
risks do not even begin to appear until a BMI of 30, and then rise only
slowly.2 Even a recent study purporting to show dangers of “overweight” actually showed decreased mortality in this group.3
There is no randomized clinical trial data showing that treatment of
“overweight” saves lives. On the contrary, there are many reports
showing that weight loss increases the risk of death.4
What has been the impact of these changing standards? In the case of
diabetes, there have been positive effects in terms of slowing the
progression of diabetes and reducing its lifelong risks. Beginning
treatment earlier in the course of the disease should prevent
complications, and new and better treatments for diabetes have appeared
at the same time that definitions have expanded. On the other hand,
many people who would never have gone on to develop dangerous levels of
blood sugar have been treated unnecessarily and subjected to the stress
and stigma of being labeled diabetic.
Setting lower target and diagnosis levels for blood pressure has
probably had a major positive impact. These benefits have accrued
because at the same time that stricter standards were set, more
effective medications with fewer side effects have been developed to
lower blood pressures. On the other hand, it is not clear that the
designation of prehypertension will have a positive influence on
health, and may promote excessive worry and health concern.
Cholesterol standards have been lowered in conjunction with a great
deal of high quality data from controlled clinical trials showing true
life saving benefits of lowering cholesterol to the new standard. One
downside is that more people will be exposed to risks of liver and
muscle damage from statin drugs, but it seems clear that the benefit of
preventing heart attacks in a large number of people outweighs the risk
of liver and muscle side effects.
Body weight norms have been lowered with no real justifying data. There
are absolutely no data from treatment trials to back up these weight
standards. Decisions about target levels for body weight cannot be
based on data about health, since these are lacking. It seems certain
that impact of lower body weight standards on health is negative.
Americans redefined as diseased as of 1998:
Diabetes—1,700,000
Hypertension—13,500,000
High Cholesterol—42,500,000
“Overweight”—30,500,000
References
Miriam Berg contributed to this article.
1. Anonymous: Relationship of blood pressure, serum cholesterol, smoking habit, relative
weight and ECG abnormalities to incidence of major coronary events:final report of the
pooling project. The pooling project research group. J Chronic Dis 1978;31:201-306.
2. Flegal KM, Graubard BI, Williamson DF, Gail MH: Excess deaths associated with underweight,
overweight, and obesity. JAMA 2005;293:1861-7.
3. Adams KF, Schatzkin A, Harris TB, Kipnis V, Mouw T, Ballard-Barbash R, Hollenbeck A,
Leitzmann MF: Overweight, obesity, and mortality in a large prospective cohort of persons 50 to
71 years old. N Engl J Med 2006;355:763-78.
4. Berg FM. Health Risks of Weight Loss. Third ed. Hettinger, ND: Healthy Living Institute; 1995.
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