More and more researchers are coming out against the US government and US health authorities and accusing them and the media of misleading the public about the health consequences of increasing body weight. Have political and economic interests taken over science?
Wyatt Gibbs, Scientific American
The obesity epidemic: an inflated balloon?
About six out of ten adults in the United States are overweight or obese. Could it be that excess fat, in itself, does not endanger their health? Could it be that those who urge in the easier cases to reduce calorie consumption and lose weight, are actually causing them more harm than good?
These ideas challenge the popular belief that excess fat kills more than 300,000 Americans a year and that the gradual increase in obesity in many nations since 1980 is a warning sign of impending epidemics of diabetes, cardiovascular disease, cancer and many other medical problems. Indeed, it was only in March 2005 that the New England Medical Journal presented a "special report", by S. G. Olshansky, David B. Allison, and others, which reinforces these fears. The authors claim that "the steady increase in life expectancy over the past two centuries may soon come to an end" because of the obesity epidemic. Articles covering this special report in the New York Times, the Washington Post, and other newspapers highlighted the prediction that obesity could reduce up to Five years of the average life expectancy in the coming decades.
Despite this, the number of researchers accusing obesity experts, public health authorities and the media of exaggerating the impact of the obesity epidemic and excess weight on health is increasing. The accusations recently appeared in a collection of scholarly books, including: "The Fat Myth" by Paul P. Campos (Gutman Books, 2004); "The Obesity Epidemic: Science, Morality, and Ideology" by Michael Gerd and Jean Wright (Routledge, 2005); "Obesity: The Making of an American Epidemic" by G. Erich Oliver (Oxford University Press, August 2005); and a book on common misconceptions about dieting and weight gain by Barry Glasner (due out in 2006, from Harper-Collins).
These critics, all of whom are academic researchers outside the medical community, do not dispute the surveys showing that the obese population has doubled in the United States and many parts of Europe since 1980. They also admit that obesity, especially in extreme cases, is indeed a factor affecting morbidity and mortality. .
However, they claim that the experts are exaggerating the issue with their warnings that excess weight and obesity are causing a serious health crisis. They mock, for example, Julie L. Garberding, head of the Centers for Disease Control and Prevention (CDC), who declared in 2003 that "if you look at all the past epidemics - from the flu to smallpox in the Middle Ages - none of them are as serious as the epidemic of cream - The rest in its consequences for the health of the country and society." (In the years 1919-1918, the flu epidemic killed 40 million people worldwide, including 675,000 people in the United States.)
Erich Oliver, a political science researcher from the University of Chicago claims that what is really happening is that "a small group of scientists and doctors, many of whose research funding comes directly from the weight loss industry, have created arbitrary and unscientific definitions for the concepts of overweight and obesity. They inflated claims, distorted statistics about the consequences of weight gain and ignored the complicated reality related to the health of the fat."
One of the complications, agrees Campos, a law professor at the University of Colorado at Boulder, is the genetic component. According to him, many agree that genetics determines about 50 to 80 percent of the differences in the degree of obesity in the population. Campos claims that since there is no safe and practical method that makes it possible to lose more than 5% of body weight long-term, the recommendation of the "health authorities to maintain a body mass index in the 'healthy weight' area" is an impossible task for most people. Body mass index or BMI is a certain ratio between weight and height.
Campos and Oliver claim that the CDC, the US Department of Health, and the World Health Organization exaggerate the level of risk from fat and the practicality of weight loss diets and thus they unintentionally perpetuate prejudices, encourage unbalanced diets and may even exacerbate the problem of weight gain. "Ironically the danger is that we may simply create a disease by labeling it as a disease," says Campos.
At first hearing, the criticism of the obesity epidemic sounds like nonsense. "If you read the medical literature and still think obesity is not a bad thing, then I don't know what planet you're living on," says James A. Hill, an obesity researcher at the University of Colorado Health Sciences Center.
New dietary guidelines published by the US Departments of Health and Agriculture confidently state that "a high prevalence of overweight and obesity in the population is a source of concern for public health because excess body fat increases the risk of premature death, type 2 diabetes, high blood pressure, excess lipids in the blood (high cholesterol), for cardiovascular disease, stroke, gall bladder disease, breathing problems, rheumatism, degenerative joint disease and certain types of cancer." The clear meaning is that any weight gain is dangerous to health and that a high body mass index is not the marker, but the cause of the high risk. "The negative medical consequences attributed to excess weight are not only exaggerated but most of them are simply false," claims Campos. Surprisingly, careful examination of the results of new epidemiological studies and clinical trials suggests that there may be something to what the critics are saying, although they may be exaggerating some of the accusations.
A very small increase
Oliver draws attention to a new and thorough analysis of the results of three large and representative surveys in which, for example, only a small, and not statistically significant, increase in mortality was found among those who are moderately overweight compared to those who are of a "healthy weight", if the effects of age, gender are offset , race, smoking and alcohol consumption. The three surveys looked at medical examinations from the early 70s, the late 70s and the early 90s and matched the subjects' names to names that appeared 9 to 19 years later in the death lists.
The results suggest that overweight American adults are less likely to die prematurely than those considered to be of a healthy weight. It seems that the segment of the overweight among those affected by the "epidemic of overweight and obesity" actually lowers the mortality rates and does not increase them. "Most Americans who are overweight are in this segment," says Campos.
Contrary to intuition, "even though only a small part of the population suffers from underweight, this phenomenon actually causes a greater number of deaths than moderate obesity," says Kathryn M. Flagel, a senior research scientist at the CDC. Flagel conducted a study whose results were published on April 20, 2005 in the Journal of the American Medical Association after it passed four months of rigorous scrutiny by internal auditors at the center itself, the American Institute for Cancer Research and additional peer review by the journal. The new results contradict two previous estimates that underpin the oft-repeated claims that obesity has shortened the lives of 300,000 or more people in the United States. There are good reasons to suspect that both of these estimates are flawed by questionable assumptions, statistical errors, and outdated measurements.
The data is inconclusive
When Flagel and her colleagues analyzed the most recent survey data, which measured heights and weights from 1988 to 1994 and collected data on deaths up to 2000, they found no statistically significant evidence that obesity, even the most extreme, increases the risk of death. Most likely, Flagel hypothesizes, that the development that has taken place in medical care in recent decades has reduced the deaths related to obesity. This is consistent, she believes, with the fact that the steady increase in life expectancy and the steady decline in death rates from heart disease and stroke have not been impaired during the 25 years that there has been a sharp increase in obesity in the United States.
And what about Olshansky and Allison's warnings that the fat are still expected to pay the price of their excess fat in two to five years of their lives? "These are just possible plausible scenarios," Ellison quipped when they didn't let him go. "We never intended to present them as accurate." Although most of the media covered the quote of "two to five years", very few bothered to mention that the article is not based on statistical analysis to support the argument.
The life expectancy cost of overweight people calculated by Olshansky and his colleagues is based on a handful of convenient but wrong assumptions. First, they assumed that every overweight American adult has a body mass index of 30 or alternatively 35 - which are the upper and lower limit values for defining the moderate level of obesity. After that, they compared the overly simple picture they received to an imaginary country where there is not a single adult with a body mass index above 24 - the upper limit of a "healthy weight" - and being underweight does not cause an increase in deaths in this country.
In order to predict the mortality rate resulting from obesity, they used relatively old risk data in their study, obtained ten years before the data used by Felgel in her study, which help to reflect the improvement that has taken place in the treatment of cardiovascular diseases and diabetes. Not only did the authors assume that the old estimate of mortality risks remained constant, but also that future advances in medicine would have no effect on the health risks of obesity.
Even if all these simplifications are reasonable, Olshansky and Allison's March 2005 article concludes, the estimated damage to the average life expectancy of the population of the United States, the world's leading country in obesity, is four to nine months. ("Two to five years" was a gloomy guess about what might happen in the "next decades" if the increase in the number of overweight children accelerates the obesity of adults).
The study did not attempt to estimate how many months, if any, the oils would lose from their lives if all the many uncertainties are taken into account. And yet, David S. Ludwig, one of the partners in the study, did not hesitate in the many interviews he gave to television and newspapers to compare the effect of the increase in obesity rates to "a tremendous tsunami moving toward the United States."
More and more researchers are coming out against the US government and US health authorities and accusing them and the media of misleading the public about the health consequences of increasing body weight. Have political and economic interests taken over science?
Medical researchers tend to warn against an expanding waistline as a harbinger of impending doom. "It raises their status and allows them to receive more research grants. Government health agencies use this as justification for financial allowances," writes Oliver. (In 2005, the NIH increased funding for obesity research by 10%, to $440 million.) "Commercial weight loss companies and surgeons use this to get their services covered by insurance," he adds. . "And pharmaceutical companies use this to justify the development of new drugs."
"The war on fat," says Campos, "is actually designed to make some of us rich." And the evidence for this is the financial support from the pharmaceutical and diet industries that many influential researchers in the field of obesity receive. Ellison, a professor at the University of Alabama at Birmingham, revealed that he was paid by 148 companies and Hill also admitted that he acted as a consultant to some of them. (Federal policy in the US prevents Pagal, and other scientists at the Centers for Disease Control and Prevention from receiving non-government pay.) However, all the disputants do not provide evidence that suggests more than an apparent conflict of interest.
Those damn diseases
Even the best mortality studies have provided a poor and incomplete picture of the expected health consequences of the obesity epidemic. Three reasons for this: First, the studies that counted all the deaths caused by obesity have so far ignored the fact that variation in body size is a normal phenomenon and therefore in any well-nourished population there are some people who are overweight. The word "epidemic" therefore refers to the sudden increase in obesity and not to its very existence. In a correct calculation of the mortality caused by the plague, only the number of deaths from obesity above normal should be estimated. Second, in analyzing the data, the researchers used the body mass index as a convenient assessment tool for the amount of fat in the body, but it is not a particularly reliable constant. And thirdly, although each of us is troubled by death, it is not the only important thing - dealing with diseases and striving for quality of life are also important.
Everyone agrees that severe obesity greatly increases the risk of contracting many diseases. But severe obesity - characterized by a body mass index of over 40 - applies to only one out of every 12 Americans who are among the 130 million adults whose weight is above the "healthy" range. The question of whether just being overweight or mild to moderate obesity also burdens the national burden of heart disease, cancer and diabetes is still an open question. Regarding heart disease, the answer is probably no - or, not yet. The health agencies in the United States do not collect annual data regarding the incidence of cardiovascular diseases, so in order to determine the trends in mortality rates and risk factors, the researchers use the data measured in periodic surveys. And in these two variables there was actually a decrease.
In the same issue in which Flagel's article was published, the study by Edward V. Gregg and his colleagues from the CDC was also published, which found that the incidence of high blood pressure in the US dropped by half from 1960 to 2000. A similar trend was also found in the incidence of high cholesterol - and both phenomena decreased steeply more among overweight and obese people than among those of a healthy weight. And so, although the prevalence of high blood pressure in the obese population is still twice that of the lean, the article claims that "their risk profile today is better (with regard to cardiovascular disease) than it was for lean people 30-20 years ago."
These findings reinforce the 2001 study conducted by the World Health Organization over 10 years among 140,000 people in 38 cities on four continents. The researchers, led by Alun Evans from Queen's University in Belfast, found an extensive increase in body mass index values and at the same time an equally extensive decrease in blood pressure and cholesterol indices. "These data are difficult to reconcile," they wrote.
Greg suggests that the improvement in the diagnosis and treatment of excess cholesterol and high blood pressure may have compensated for any increase in the prevalence of these diseases due to the increase in obesity, and more. It is also possible, he says, that overweight people exercise more today than they did before. Regular physical activity is considered an effective preventive measure against heart disease.
Obesity as a side effect
Oliver and Campos raise another possibility: to some extent obesity itself is only an outward sign of other, even more important, factors that are difficult to discern. The composition of the diet, physical fitness, levels of mental stress, financial income, family history and the location of fat in the body are just a few of the more than 100 additional and "independent" factors for heart disease defined in the medical literature.
The observational studies that linked obesity to heart disease ignored almost all of these factors, thus establishing the apparent causes of obesity. "In the same way that we blame obesity for heart disease," writes Oliver, "we could blame smelly clothes, yellow teeth, or bad breath for lung cancer instead of cigarettes."
And as for cancer, a report published in 2003 summarizing sixteen years of research in which 900,000 American adults were examined showed an increase in the death rate from some types of tumors among those who were overweight or moderately overweight. Most of these types of cancer, which are probably related to obesity, are extremely rare types - at most a few dozen people died from them per year out of all 100,000 study participants.
Among women with a high body mass index, a slight increase in the risk of breast cancer after menopause, and colon cancer was found. In men with excess weight or excess fat, an increase in the risk level was found, mainly from colon cancer and prostate cancer. On the other hand, it was found that both women and men who are overweight or obese actually benefit from protection against lung cancer, which is undoubtedly the most common type of deadly malignant cancer. The finding is valid even if the smoking factor is removed
The nutritionist
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