Bent Out of Shape

Though Michael Booth is a scientist, he delivers a speech like an actor. What he's about to say is "pretty frightening stuff," he tells an audience of mostly fellow academics in Sydney. "It should be R rated. It's not for the faint-hearted." And sure enough, Booth's lecture—on the results of a survey that found almost 25% of New South Wales pupils from infant school through Year 10 are overweight or obese, double the figure of 20 years ago—is chilling. After Booth, a researcher on adolescent health at the University of Sydney, reports some statistics about how much time kids spend staring at small screens, he draws in his audience with, "Pretty scary, isn't it?" After suggesting that a proportion of children are already on their way to developing diseases for which obesity is a risk factor, he observes that "we're sick and we're getting sicker." And in case anyone's less concerned with deteriorating health than with its costs, Booth warns that if governments don't get serious about obesity and corpulent teenagers don't make changes to their lifestyles, the nation's health system could one day "crack like a peanut under an elephant's foot."

It's enough to make you tremble, but are things really so bad? In the new and burgeoning field of obesity research, there was nothing unusual about Booth's address last month. In Australia and New Zealand, as in many Western countries, to open a newspaper or switch on the T.V. is to be assailed by another dire take on what the World Health Organization calls the "worldwide epidemic" of obesity. Clearly, it isn't just the more sensationalist elements of the media but a host of research centers and health bodies that have categorized the trend toward increasing body mass in humans as an impending disaster. The bleak diagnosis is that as a species we're carrying too much lard, exposing every system of the body to heightened risk of disease. Amid constant warnings about soaring rates of diabetes and links between fat and heart attack, stroke, dementia, cancer, arthritis and a myriad of other conditions, a view is taking hold that obesity will reverse the millennium-long trend of rising human life expectancy—that today's children will die younger than their parents. In Australia and New Zealand, various groups are pushing for numerous anti-fat measures, including taxing high-kilojoule foods, restricting junk-food advertising and cranking up the frequency and intensity of physical education classes in schools.

Concern about obesity hasn't sprung from nothing. There's no question that people are getting bigger. Even the most strident obesity skeptics concede that across Western populations, adults are on average 7 kg heavier than they were 25 years ago. Nor does anyone dispute that, according to the standard measuring tool of body mass index, or BMI (which is calculated by dividing body weight in kilograms by height in meters squared), the majority of Australian and New Zealand adults are either overweight or obese. Based on its National Health Survey 2004-05, the Australian Bureau of Statistics reports that 62% of men and 45% of women are above their ideal weight range (up from 52% and 37% respectively in 1995). Nor is there any argument that body weight has some relationship to health. Clearly, being severely obese (or severely underweight) is a recipe for trouble.

What's open to debate is whether all this amounts to a crisis. But instead of measured debate, what people are hearing is a chorus of obesity alarmism. There's another side to the obesity story. Argued with varying degrees of fervor by epidemiologists, skeptics and sundry others, it points out the arbitrary nature of the BMI classifications, throws doubt on attempts to link high BMI and premature death, asks who stands to gain from the fanning of obesity fears, and questions the value of hounding populations to lose weight. "In general, we just don't know what the long-term consequences of rising obesity are going to be," says N.S.W. academic Michael Gard, coauthor with Jan Wright of The Obesity Epidemic: Science Morality and Ideology (2005). "But is it the looming, drop-everything health catastrophe that we're told it is? We say no." One thing highlighted by the obesity issue is how far apart the pronouncements of parts of the scientific community and the gut feelings of ordinary people can be. The ABS's National Health Survey tells us that most Australians consider themselves to be in very good or excellent health, and that the most commonly reported complaints are not ghastly complications of obesity but poor eyesight, hay fever, allergies and sore backs. And while BMI tables say many of them are wrong, nearly two-thirds of respondents consider themselves to be of acceptable weight.

Nowadays, you don't have love handles, puppy fat or a spare tire—you're overweight or obese. And obesity is a disease. That's the term of choice, anyway, for health authorities such as the Australasian Society for the Study of Obesity, which says obesity "is a complex and multifactorial disease." But obesity—defined as a BMI of 30 or greater—is no more a disease than is cigarette smoking or sedentary living. People can be obese but healthy, just as they can be thin and sick. "It really doesn't make sense to call obesity a disease—it's a risk factor," says Stephen MacMahon, principal director of The George Institute for International Health, in Sydney. Moreover, it's a risk factor for maladies—heart disease, stroke, and even type 2 diabetes—that strike thin people, too.

So why is it being called a disease? Here, many analysts see the fingerprints of the pharmaceutical industry, which worldwide has more than 20 weight-loss drugs in clinical trials and another 30 in the pipeline. But more on that—and obesity's links to illness—later.

Another habit of obesity alarmists is to conflate those labeled as overweight with those classed as obese, and talk about them as a single group. For example, instead of saying that about 1 in 5 Australian and New Zealand adults is obese, many experts tend to say that more than half of both populations are overweight or obese. There'd be no problem with that if the two groups' different BMI classifications put them at equal risk of early death. But that's not the case. Indeed, there's compelling evidence that those defined as overweight (with a BMI between 25 and 29.9) are no more likely to die prematurely than people of ideal weight.

Published last year in the Journal of the American Medical Association, a comprehensive study designed to associate BMI and death risk sent shock waves through the international medical community. A research group led by Katherine Flegal, a senior epidemiologist at the U.S. Centers for Disease Control and Prevention, analyzed data from several large U.S. health studies conducted between 1976 and 2000, controlling for factors such as smoking, age, race and alcohol consumption. They found that while obesity caused about 112,000 deaths a year, being overweight prevented about 86,000 deaths annually. Based on those figures, the net U.S. death toll attributable to excess weight is 26,000 a year (about one-twelfth the figure that many obesity experts had been fond of quoting). But this was more than canceled out by the 34,000 deaths that researchers linked to being underweight—having a BMI lower than 18.5. What to make of pudginess appearing to prolong lives? Study coauthor David Williamson speculated that since most people are over 70 when they die, some extra fat might have a protective effect in old age.

While some analysts condemned the study as flawed, its findings delighted University of Colorado law professor Paul Campos, whose provocative book The Obesity Myth was published in 2004. The Flegal study, he says, confirmed at least two of his firmly held views: that the BMI's overweight category is meaningless and that you see a significant increase in the risk of premature death only at the two extremes of weight distribution. "The vast majority of people who are being judged as weighing too much by public health authorities throughout the Western world are at a weight where there isn't even a correlation with increased health risk, let alone a causal relationship," says Campos. The notion that overweight and obesity turn people into medical time bombs "is being exaggerated by roughly a factor of 10," he says. "An argument that may be relevant to the heaviest 6% of the population is being applied to 65% of the population."

The obesity epidemic, Campos argues, amounts to a relatively small across-the-board weight gain pushing large numbers of people from the top of the ideal-weight category into overweight, and from the top of overweight into obese—subtle shifts, in other words, rather than alarming spikes. Support for that view can be found in creeping mean BMI readings for New Zealand men: they've gone from 25.5 in 1977 to 26.9 in 2003. The starting point for overweight used to be 27, until health authorities—following the W.H.O.'s lead—lowered it in the late 1990s.

The consensus among obesity researchers is that people began getting heavier in the 1970s and have continued to do so. While skeptics don't dispute this, they say that if the extra weight is a problem, it should be reflected in rising death rates from cardiovascular disease. In fact, the opposite has occurred. In March, a month after launching a $A6 million advertising campaign aimed at getting kids to be more active and saying, "obesity is a very serious problem in our society ... obviously it leads to cardiovascular disease," Australia's Minister for Health and Ageing Tony Abbott told a National Heart Foundation conference in Sydney: "There has been a truly remarkable drop in the death rate from cardiovascular disease. Since the 1970s ... [it ]has dropped by 60%."

What's happened, most doctors would say, is that better treatment, broader use of drugs for prevention, as well as less cigarette smoking, mean that despite rising average weight, fewer people are dying from cardiovascular disease. This is small cause for celebration, says Sydney University's Booth. "People who are overweight are more likely to suffer serious, debilitating, chronic diseases before they actually die. We've become quite good at keeping people alive in the presence of these diseases, but they have a really poor life in the meantime, and that doesn't show up in studies like Flegal's."

If plunging cardiovascular death rates are a stumbling block for those trying to push the obesity panic button, then type 2 diabetes—studies suggest it afflicts more than 7% of Australia's adult population, twice its prevalence 20 years ago—is a hitch for skeptics. A disease strongly correlated with obesity and once almost exclusively associated with ageing, type 2 diabetes appears to be striking more people, and earlier. For the N.S.W. Schools Physical Activity and Nutrition Survey 2004 (SPANS), researchers took blood samples from 500 Year 10 students and found elevated insulin levels—a precursor to the disease—in almost 20% of them. Some researchers argue that obesity may be an early symptom of diabetes rather than a cause of it. They say eating better and exercising more are much better ways of preventing diabetes than shedding fat, and that the number of diabetes sufferers has been inflated by shifting diagnostic boundaries. Nonetheless, diabetes is probably the strongest card the alarmists hold.

Bombarded by doomsday obesity messages, however, people may expect that, sooner or later, the trend of rising weight will start chipping into average life expectancy. But here's another evidentiary problem for those beating the obesity drum: life expectancy in Australia is slated to go on increasing for at least another half-century. According to ABS projections, an average 50-year-old in 2051 will live to age 87; an average woman to 89. These represent increases of six and 4.5 years respectively on projections for the current crop of 50-year-olds. So how should we reconcile apparently being in the midst of an unprecedented health crisis with the official prediction that we'll be living longer than ever? Invoking Occam's razor, Campos says "the simplest explanation is that there is no crisis."

Others worry that the preoccupation with obesity will discourage people from thinking about their health in a balanced way. More than 80% of cardiovascular disease is explainable by some combination of smoking, high blood pressure, high cholesterol, obesity, diabetes and sedentary living (being male works against you, too). Generally, the poor sod who collapses from a heart attack could tick three or more of those boxes. "We've been fighting to stop doctors and patients thinking about any of these risk factors in a vacuum," says The George Institute's MacMahon, professor of cardiovascular medicine and epidemiology at the University of Sydney. "Your risk of having a heart attack is very, very multidimensional. Obesity is a causal contributor, but it's one of many. And it's actually much harder to reduce weight than it is to lower blood pressure or cholesterol. Fundamentally, all these risk factors multiply one another, so if you can't turn one down, you turn others in the chain and you end up with the same sort of result." If you must fret about one risk factor, adds George Institute senior epidemiologist Rachel Huxley, then make it smoking, which more than 20% of Australian adults do regularly. "You've got a 50:50 chance of it killing you," she says. Statistically speaking, "if you and your best friend smoke, one of you will be killed by it."

In the same vein, Adrian Bauman, director of the Australian Centre for Health Promotion, notes that high blood pressure and cholesterol, as well as physical inactivity, are more prevalent in the population than obesity. "Yet obesity has captured the hearts and minds of the media," says Bauman. "And it's done that because it's graphic. It is depictable. It's boring to show physical inactivity, because it's just people being inert." Likewise, increasing weight is relatively easy to measure, he says. "So all of a sudden we have an epidemic of obesity interest. Not that we haven't got a problem with obesity. We do. But it's a combined problem along with a cluster of lifestyle things."

Skeptics argue that far from being a fact, the obesity epidemic is a potpourri of scientific, moral and ideological assumptions. One of these—that fat is bad and will eventually make you sick—ignores evidence that high BMI is associated with lower incidence of numerous diseases and syndromes, including some cancers, emphysema, anemia, bronchitis, osteoarthritis and hip fracture. It also skirts the evidence for fat, in many cases, being little more than a benign marker of an individual's genetic predisposition to carry it. According to GPs, there are many people who eat sensibly, exercise regularly and have excellent health readings—but have a BMI well over 25. "You can be thin," says The George Institute's Huxley, "and have a much worse cardiovascular profile than if you were fat but fit."

But let's assume for a moment that a high BMI score is a health hazard. What then? What advice should health authorities give to the more than 1.3 billion people in the world who would supposedly benefit from losing weight? The standard tip has been to eat less and move more, which presupposes that people eat more and move less than they did a generation ago. A typical media portrayal of today's child is of a fatso slumped in front of a video game, guzzling soft drink and not faintly inclined to venture outside to kick a ball or climb a tree. But this perception buckles under scrutiny. From the SPANS school survey, Michael Booth reports that while few pupils walk to school any more and cycling there has all but vanished, a huge majority are performing the recommended one hour a day of moderate-to-vigorous physical activity. Moreover, both girls and boys are much more active than their counterparts of 1985 and 1997. Booth told his audience in Sydney that these results "stunned" him, appeared to "defy belief" and "were checked to within an inch of their lives." The report states: "Perhaps surprisingly, the survey did not show any clear correlation between BMI and the amount of physical activity."

As for eating, SPANS homed in on a few bad habits, but nothing startling compared with childhood decades ago, while academic Gard says the "serious epidemiological data on food consumption [show ]we've been eating fewer calories each decade since the 1920s." Less food. More exercise. So why are people getting heavier? Some analysts say we just don't know. Others theorize that what we're seeing is a continuation of increasing body mass in well-nourished nations, helped along by falling smoking rates. "I'm not arguing that we know for a fact that the increased weight level of people in developed nations is entirely benign," says author Campos. "It might not be. But it very well might. Given that we don't know the underlying causes ... the best approach is to ask whether people's overall health is getting better or worse. It's clearly getting better. The only reply the obesity alarmists have to this is that it will stop getting better and start getting worse."

But let's stay with the idea that most adults should be trying to get thinner. Even if it has no effect on weight, doing a little more exercise will probably improve health. But dieting is more problematic. As most people who've tried it will attest, dieting with a goal of achieving lasting weight loss is all but guaranteed to fail. According to the Eating Disorders Foundation of Victoria, 95% of people who go on weight-loss diets regain everything they've lost and more within two years. But why? Do all these people lack self-control? Highly unlikely. Proponents of the set-point theory argue that everyone's body is biologically programmed to stay around a certain weight and will fight attempts at maintaining a weight more than 2-3 kg below that set point. Given less food than it's used to and responding to a drop in leptin, a hormone produced by fat cells, the body clicks into survival mode, slowing metabolism to save energy and triggering cravings for high-kilojoule foods. Now what may be looming for the dieter is months or years of fluctuating weight, possible use of potentially dangerous weight-loss pills, a heightened risk of binge eating and other eating disorders, feelings of failure and social withdrawal—factors that may partially explain the premature deaths of a proportion of obese people.

In a paper published in February in the International Journal of Epidemiology, Campos and others reviewed what medicine knows about how fat—or adiposity—is supposed to cause disease. They concluded that with the exception of osteoarthritis, where increased weight contributes to wear on joints, and a few cancers where estrogen originating in fat tissue may play a role, "causal links between body fat and disease remain hypothetical." They cite a recent U.S. study that found women who'd had an average of 10 kg of fat removed by liposuction had no improvements in health markers over the next three months. By contrast, it's well established that people who merely add a little exercise to their lives can improve their health profile—though not necessarily their thigh or waist measurements—in the same period.

If fat is not itself pathological, what's driving the obesity panic? In the same article, the authors point out that many of the world's leading obesity researchers who've been involved in defining overweight and obesity have received funding from the pharmaceutical and weight-loss industries; some manage weight-loss clinics themselves and so have "an economic interest in defining unhealthy weight as broadly as possible
and overstating the hazards of obesity." While stressing he's not an obesity expert, David Henry, professor of clinical pharmacology at the University of Newcastle, notes the potential for disease mongering among the overweight, and the gold-plated possibilities for drug companies, in a broad perception of an obesity crisis. "There aren't many frontiers left for mass-population treatment drugs," says Henry. "The blood pressure, cholesterol and mood-disorder drugs are all coming off patent. Obesity and substance abuse are probably the final two frontiers for drugs taken by huge numbers of people, year after year ... they're the golden egg of drug development."

This issue is not black-and-white. David Whiteman, a Queensland Institute of Medical Research cancer epidemiologist, is in Seattle studying risk factors for a rare type of esophageal cancer whose incidence has risen in Australia recently. His conclusion—not yet reviewed by peers—is that "obese people have consistently raised risks of esophageal adenocarcinoma and that this risk is apparent even for modestly overweight people." On the more general issue of the risks of rising BMI, Whiteman says: "A few extra pounds is probably not going to hurt people and may even be advantageous to long-term survival. The problem is that most Australians carry considerably more that just a few extra pounds. In addition, people are getting fatter at younger ages. We don't yet know what the long-term consequences of childhood obesity are, but I would suggest that this is an undesirable trend from a health perspective."

Nonetheless, a little perspective is overdue. Authors Gard and Wright observe that despite the insistence of many scientists that overweight and obesity are diseases, other people can see that it's quite possible to be healthy, happy and large. "Perhaps," they write, "even without the benefit of a scientific education, people sense that the pathways that lead from overweight and obesity to premature death are extremely indirect ... that food should be enjoyed, not agonized over. Perhaps they see that, given the health challenges that currently face different parts of the world, describing entire Western populations as sick seems a bit of a stretch." Perhaps what most needs letting out is not the pants of the average Jack and Jill, but some air from the bubble that is obesity hysteria.