TCS Daily


Where's the Epidemic?

By Sandy Szwarc - July 30, 2003 12:00 AM

"The war on fat has reached the point where the systematic distortion of the evidence has become the norm, rather than the exception," wrote Paul Campos in the Rocky Mountain News on April 2, 2003. Campos is professor of law at the University of Colorado and author of the upcoming "The Last American Diet."

 

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To Do List
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A Simple Plan
08/08/2003
Mikey Doesn't Like It
08/06/2003

As many have recognized, the "fat is unhealthy and undesirable" premise has become preordained not just among consumers, but the scientific community we well. The National Association to Advance Fat Acceptance's (NAAFA) policy on Obesity Research notes that scientific research and public policy have historically operated with the sole goal of making fat people thin, believing that permanent weight loss is not only possible, but that it improves health and longevity. "Unproven assumptions about fatness frequently invalidate the basic premise of research studies," it states.

 

In their comprehensive review of the scientific evidence on obesity treatment, published by Clinical Psychology Review in 1991, David Garner, Ph.D. and Susan Wooley, Ph.D. concluded: "Evidence that it is more dangerous to be thin than fat is either ignored or minimized in analyses that shape public policy toward weight loss."

 

But, it has been on such questionable research, or no clinical proof at all, that our public policies on obesity have been built. In 1977, the National Institutes of Health (NIH) conference first labeled obesity a disease, but by their 1985 conference they had upped the dangers, declaring it a "killer disease" and suddenly making even being mildly overweight a health risk. Along with these assertions came weight loss recommendations for this expanded group of Americans that translated into billions of research dollars, commercial weight-loss industry profits and doctors' revenues.

 

In 1998, the rhetoric became more exigent, when NIH changed the definition of overweight from those with BMIs (body mass indexes) over 27, to those with BMIs of 25 or greater. That instantly deemed an estimated 29 million more Americans overweight and in need of weight loss -- folks like Michael Jordan and Brad Pitt.

 

Across the nation, public health officials and heath care industry representatives are now declaring obesity a public health crisis.

 

Is it really possible that fashion ideals have blurred the objectivity of scientific study and public policy to the point fatness has been declared a national health crisis? Let's look at some of the ways the evidence on obesity has been "shaped" to support the war on obesity.

 

The Birth of the 'Fat Kills 300,000' Myth

 

The justification for the war on obesity, used by most government officials, healthcare providers, diet industry representatives and special interest groups today, is that "obesity causes 300,000 deaths a year." That figure's been repeated so often it's taken as fact. But, its origins are a classic case of bad science run amuck.

 

It all started with a Nov. 10, 1993, study by Michael McGinnis, M.D., and William Foege, M.D., in the Journal of the American Medical Association (JAMA). They had done a Medline database search of articles published between 1977 and 1993 in which estimates were made of factors contributing to U.S. deaths. After tobacco, they attributed 300,000 deaths to lifestyle factors: sedentary activity levels and poor diets.

 

Those factors, as we've seen, don't equal obesity. In fact, Drs. McGinnis and Foege didn't even evaluate weight as a risk factor. They also ignored other factors such as dieting and diet drug use. "Nor were variables such as class -- poor people die sooner than the well-off -- and social discrimination, which has been shown to have a very negative impact on health, taken into account," Campos noted.

 

The researchers' numbers weren't from counting actual deaths, but calculated using a formula for "attributable risk." They even stated in their study that, because the articles they reviewed used different approaches to derive estimates, their numbers "should be viewed as first approximations."

 

But, subsequent researchers have taken that 300,000 figure as a foregone conclusion and it's appeared in hundreds of studies since. Even worse, Drs. McGinnis' and Foege's "lifestyle factors" -- being sedentary and eating poor diets -- have been misinterpreted as "obesity."

 

A mountain of studies has seemed to "prove" a link between obesity and higher mortalities. But did they really, or was it a case of scientists seeing what they set out to find?

 

The largest study ever conducted, published in JAMA in January 1998, reexamined questionnaires from an American Cancer Society study and calculated 324,135 participants' BMIs. Head researcher, June Stevens, Ph.D., claimed the relative risks for morbidity were greater in those with higher BMIs, up until age 75, and that the risks were greatest for younger people. Using the same data, another report appeared in American Journal of Epidemiology, which concluded that "obesity adds years to your real age." These findings saturated press releases and media headlines.

 

A number of their scientific peers, however, noted significant problems with the studies, among them the recognized unreliability of questionnaires, using figures from studies not designed to actually test for what the researchers were later trying to extrapolate and, most notably, difficulties in interpreting "relative risk."

 

Relative risk calculations don't involve clinical testing or actually measuring anything, but are used by epidemiologists to gauge the importance of various health problems. A relative risk of 1 means one factor is the same as another. Stevens' stated findings were that the relative risk of mortality from heart disease related to BMI was 1.10 in men and 1.08 in women ages 30 to 44 years; and 1.03 in men and 1.02 in women ages 65 to 74 year old.

 

Reviewers were quick to condemn these inconsequential numbers. As the National Cancer Institute has stated: "In epidemiologic research, relative risks of less than 2.0 are considered small and usually difficult to interpret. Such increases may be due to chance, statistical bias or effects of confounding factors that are sometimes not evident." In other words, the study's conclusions were flimsy. Critics also questioned the interpretation of those numbers, noting that younger people have fewer disorders, so the relative risk of anything would appear higher; and that there were actually no increased risks found among those overweight, versus obese.

 

In an attempt to curtail the now rampant "fat kills" legend, New England Journal of Medicine (NEJM), editors Jerome Kassirer, M.D., and Marcia Angell, M.D. -- with 36 scientific references backing them up -- argued in two 1998 editions that scientific and medical research did not support the obesity-death link. "The data linking overweight and death, as well as the data showing the beneficial effects of weight loss, are limited, fragmentary, and often ambiguous. Most of the evidence is either indirect or derived from observational epidemiologic studies, many of which have serious methodological flaws. ... [T]hat [300,000] figure is by no means well established. Not only is it derived from weak or incomplete data, but it is called into question by the methodologic difficulties of determining which of many factors contribute to premature death. ... Calculations of attributable risk are fraught with problems ... when several known factors [physical inactivity, low fitness levels, poor diet, risky weight loss practices, and less-than-adequate access to health care, to name a few] are taken into account, it is even possible that they account for more than 100 percent of deaths -- a nonsensical result."

 

For going against what had become politically correct, the editors were crucified in the media, by obesity researchers, and even former U.S. Surgeon General C. Everett Koop.

 

Drs. McGinnis and Foege were so concerned that their study results were being misinterpreted they even wrote a letter in NEJM on April 16, 1998, but they, too, were ignored by the media and most of their peers.

 

Researchers and public officials were increasingly reporting not just that 300,000 deaths were linked to obesity, but suddenly caused by obesity, too. Most, like a study published in JAMA, Oct. 27, 1999, didn't actually specify what obese people were dying from. But as the author, David Allison, Ph.D., noted, "our calculations assume that all excess mortality in obese people is due to their obesity."

 

The "fat kills 300,000" myth was born.

 

Other Troubling 'Evidence'

 

"In the 15 years I have been reporting this scene," wrote Frances Berg, M.S., editor-in-chief of Healthy Weight Journal in a May-June, 1998 editorial, "I have often observed the risks of obesity being exaggerated in academic and federal reports, while eating disorders, dysfunctional eating, nutrient deficiencies, and the hazards of dangerous weight loss they treatment are ignored or minimized."

 

When it comes to the war on obesity, faulty interpretations of scientific data are rampant:

 

Equate association with causation. Even respected doctors tout reams of numbers showing correlations between fat and heart disease or cancer to support the obesity crisis. But just because a group of fat people have certain health problems does not mean that their weight caused the problems. It's like concluding that since everyone who has cancer once ate a pink cupcake, that pink cupcakes cause cancer. It could have been a zillion other things.

 

Likewise, many studies merely crunch numbers to arrive at associations, or combine obesity with mortality figures for diabetes or heart disease because of their "belief" that fatness caused these conditions. Those involving clinical trials to demonstrate obesity-related causation are far and few between. Only two conditions have been proven to be directly caused by obesity, points out Paul Ernsberger, Ph.D., of Case Western Reserve School of Medicine: osteoarthritis of weight-bearing joints and uterine cancer due to obese women's higher estrogen levels and absence of proper medical attention.

 

Consider only one possibility -- fatness. When analyzing findings, to avoid incorrect conclusions the soundest studies investigate all alternative explanations. But in studies cited as evidence for the risks of obesity, confounding factors such as physical inactivity and fitness levels, poor diet, socioeconomic status, race, age, and gender are often disregarded.

 

Dieting is almost never considered as being a contributing cause, even when researchers note the subjects have all lost and regained considerable weight. Yet as we've seen, dieting and weight loss treatments have profound impacts on mortality and illnesses. For example, a weight loss study of previously healthy fat men led by E. J. Drenick, M.D., in the Feb. 1, 1980, JAMA, concluded: "It appears that no unusual factors other than obesity could have caused such extraordinary [referring to a 12 times greater] mortality."

 

Finding fat populations in developed countries who haven't dieted is next to impossible in today's thin obsessed world. But back in the 1960s, researchers at the University of Oklahoma found communities of Italian-Americans who were happy with their weights -- many were very fat and ate plenty of rich high-cholesterol foods -- and virtually free of all the diseases supposedly attributed to fatness. Even as early as 1952, the Mayo Clinic found that fat people who stayed fat had a better chance of surviving a coronary than slim people or those who tried to diet. Numerous similar findings were found during the 1960s, before dieting became pervasive.

 

Conclude study results inconsistent with the data. When it comes to obesity, regardless of the data, researchers oftentimes conclude what they set out to prove. They know most people will merely skim the abstract anyway, or the media will do it for them.

           

For example, an American Cancer Society study published in this year's April issue of NEJM claimed to find irrefutable evidence of increased cancer deaths in higher BMIs and that 90,000 lives could be saved from cancer if BMIs were under 25 throughout a lifetime. In actuality, critics noted, the data found the lowest cancer risk in those with BMIs 25 to 29.9 (considered overweight), a fact also omitted from all major media stories. The risks were negligible in overweight and obese patients until subjects reached a BMI of 40 and above, and even then, extremely obese women had lower cancer risks than the slimmest men.

 

Generalize results from one studied group to broad populations. Like that cancer study, the negative health consequences of obesity appear to largely afflict those at extreme levels of obesity, BMIs of 40 or greater, which is a mere 4.7 percent of the population. Despite the fact a small fraction of Americans are most at health risk from obesity, everyone's told they need to lose weight. And, most diets are directed towards women, although the negative health consequences of fatness are most serious in men.

 

In women with BMIs of 40 and above, their life expectancy is reduced by 5 years, Ernsberger said. "Yet these extremely obese women still have a longer life expectancy than normal-weight men."

 

Few studies have been done on minority populations or those with BMIs over 40, leaving scientists to mostly speculate as to the actual risks in these groups.

 

Where's the Epidemic?

 

Sensationalizing statistics and exaggerating claims of a crisis aren't found in sound scientific inquiry, as neutrality and reasoned analysis are fundamental. So not surprisingly, despite all the hysteria behind the "epidemic of obesity" supposedly threatening our nation, and now the world, many experts have found it's been blown all out of proportion.

 

Not only is the term "overweight" arbitrary, unrelated to health, and been redefined over the years, it's used interchangeably with "obese" to heighten the crisis. Everyone with BMIs of 25 or greater are lumped together with the minority of those extremely obese to comprise the "more than half of U.S. adults" considered fat, as did the study led by Aviva Must, Ph.D., in the October 27, 1999, issue of JAMA.

 

Yet, do those rising numbers of fat Americans actually translate to an individual or national health crisis? Hardly. Because the incidence of obesity is defined as a threshold, a small increase in average weights has a disproportionate effect, Jeffrey M. Friedman, M.D., Ph.D., at Rockefeller University, explained in a Feb. 6, 2003, press release. Although the incidence of obesity in the United States has increased from 23.3 percent in 1991 to 30.9 percent today, the weight of the average American has increased only 7 to 10 pounds on average, he pointed out.

 

Furthermore, it's a strange epidemic that finds those exposed to it living longer, healthier lives than ever before. Yet, that's exactly what Department of Health and Human Services statistics show, even as the population is getting fatter and simultaneously aging. Given that the NIH and WHO have claimed obesity is second only to smoking as a preventable cause of death, then increases in adult obesity should have a negative impact on life expectancy, Ernsberger noted. "The opposite is true. Death rates have fallen. The greatest improvements are in cardiovascular disease deaths, which are most strongly linked to obesity," he said. "The decline in age-related mortality for stroke is 59 percent from 1970 to 1994; for heart disease, 53.2 percent."

 

As for the $93 billion [to $117 billion, depending on whose figures you want to use] "costs" of obesity? Mere hype. With doctors, researchers and politicians attributing everything that happens to fat people as the fault of their fatness, medical expenses for all of their health problems are included, Glenn Gaesser, Ph.D., associate professor of exercise physiology at the University of Virginia, has noted. A closer look reveals these dollar cost estimates also tally ambiguous tabs of "reduced productivity," absenteeism, higher insurance premiums, litigation and even the ineffective weight loss treatments they themselves promote.

 

Cautionary Note


NAAFA observed in its Obesity Research policy statement, that the leading obesity researchers all have enormous economic stakes in seeing expanded forms of obesity treatment applied to more Americans.

Oftentimes the most knowledgeable experts are within industries. That's not always a problem. But in the case of obesity, Thomas Moore, M.D., of Boston University School of Medicine, observed, "Due to their economic interests and bias, a suppression of research antithetical to the diet industry's position exists. Research not supporting weight loss isn't funded and isn't published."

In any event, as Campos wrote in the New Republic in January: "[T]he conventional wisdom about fat in the United States is based on factors that have very little to do with a disinterested evaluation of the medical and scientific evidence, and therefore this conventional wisdom needs to be taken for what it is: a pervasive social myth rather than a rational judgment about risk."

 

On Friday: Are there benefits to middle-age spread?

 

© 2003 Sandy Szwarc. All rights reserved.
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