Overselling the obesity epidemic isn't getting us anywhere. You can be big and healthy at the same time.
By Daniel Heimpel | Newsweek Web Exclusive
Aug 27, 2009
In late June the Centers for Disease Control and Prevention launched its LEAN Works Web site, a clearinghouse of information on the health costs of employing fat people replete with recommendations on how to prevent and control obesity. The site uses an "obesity cost calculator" to determine the added price of employing somebody with a body-mass index (BMI) of over 30, the threshold for obesity. The calculator asks employers to fill out a company profile including type of industry and location, employees' BMIs, and their wages and benefits. The software then estimates the "costs for medical expenditures and the dollar value of increased absenteeism resulting from obesity."
But is the federal government's endorsement of a device that essentially demonizes the 72 million Americans who fit the official definition of obese justified by the science? Dr. William Dietz, director of the CDC's Division of Nutrition, Physical Activity and Obesity, defends the site as one weapon in the larger war on fat. "We see this epidemic as a serious threat to health and serious medical cost," Dietz says. "We didn't feel like we could wait for the best possible evidence, so we acted on the best available evidence."
Other experts, however, say BMI is a crude tool that fans fears of an obesity epidemic even as it fails as a reliable measure of an individual's health. "We made everyone fat by framing! That is the real epidemic," says Paul Campos, a law professor at the University of Colorado who coauthored a controversial study questioning whether obesity is a true health crisis or a moral panic.
The American Heart Association lists obesity as major risk factor for heart disease because it raises blood pressure, increases "bad" cholesterol while lowering "good" cholesterol, and carries an elevated risk of developing diabetes, itself a risk factor for heart disease. In addition, obesity has been linked to a wide range of health problems, including cancer, asthma, and sleep apnea.
Nevertheless, it's hardly clear that there actually is an obesity epidemic, or that fat people are at greater risk of death than people of normal weight, or that weight loss—relentlessly promoted by public-health officials as the solution to America's weight problem—is an attainable goal at all.
When we talk about the obesity epidemic, it's important to understand where the numbers come from. Most large-scale evaluations of public fatness—including the CDC's—employ BMI, a calculation that uses an
individual's height and weight to determine whether he or she is underweight (BMI less than 18.5), normal weight (BMI between 18.5 and 24.9), overweight (BMI between 25 and 29.9), or obese (BMI of 30 or higher). BMI calculations can be famously ridiculous—Dallas Cowboys quarterback Tony Romo's BMI of 28.8 (he's 6 feet 2, 224 pounds) puts him at the upper end of the overweight category.
In the 1970s, the average BMI in the U.S. was 24. Today, the average BMI is only three points higher, at 27. If you were to look at two people, one six feet tall, weighing 180 pounds, with a BMI of 24, and another six feet tall and 199 pounds, with a BMI of 27, you'd be hard-pressed to say the latter was overweight. But in 1995 the World Health Organization decided that a BMI of 25 or over was considered overweight because of evidence of heightened health risks at that level—thus pitching the average American into that category. Suddenly, 66 percent of us were overweight.
Campos argues that the average person, without understanding how BMI works, takes the startling numbers at face value, which unnecessarily heightens fears of an obesity epidemic. When the CDC proclaims that one third of us are obese, the result is a toxic combination of stigmatization and dread, because, as Campos notes, obesity has become a "pathologizing term." But, as his paper explains, the case against fat is both inconclusive and blown out of proportion. "The current rhetoric about an obesity-driven health crisis is being driven more by cultural and political factors than by any threat that increasing body weight may pose to public health."
While the number of obese Americans has doubled since 1980, the obesity rate for adults has plateaued, with no change between 2003 and 2006, the most recent year for which the CDC has data for adults. And in a report released by the agency last month, obesity rates among low-income preschool-age children, one of the focal points for fear over runaway fat, hovered at about 15 percent from 2003 through 2008. University of Chicago public-health professor S. Jay Olshansky says this leveling-off of high BMI levels is not a good sign: "Things aren't getting worse, because they can't get any worse." Olshansky coauthored a paper in 2005 [http://www.nih.gov/news/pr/mar2005/nia-16.htm] predicting that the rise in obesity-related type-2 diabetes would reverse the national trend of increasing life spans. He notes that 20 million adult Americans currently have diabetes, twice as many as 10 years ago, according to a July report by the Trust for America's Health and the Robert Wood Johnson Foundation .
However, a widely cited study by the CDC's National Center for Health Statistics found no evidence that being overweight or moderately obese as an adult increases the risk of death. Indeed, the paper, which synthesized a wealth of previous reports on mortality, found quite the opposite. "One of the things that people found surprising was that according to our estimate, overweight [a BMI of 25 to 29.9] wasn't associated with any excess mortality overall and in fact with slightly reduced mortality," says Katherine Flegal, the CDC researcher who conducted the study, which compared life expectancy for people in different BMI categories. For people considered moderately obese, mortality was slightly increased over normal-weight people, but not more than people who are underweight.
A study published last month in the Annals of Surgerysupported this "obesity paradox." The report, which looked at more than 100,000 patients who had undergone nonbariatric general surgery, found that overweight and moderately obese patients had mortality rates 15 and 27 percent lower, respectively, than normal-weight patients. One of the study's coauthors, Dr. Donald Moorman, of the Beth Israel Deaconess Medical Center in Boston, speculated that the excess weight could provide stores of protein to supply the healing process. "Perhaps this group has been identified as doing better because they are less nutritionally depleted, and thus their healing factors are much better," he says.
Other studies have shown that when patients are admitted to emergency treatment for heart or kidney failure, carrying extra weight isn't necessarily a problem. A 2008 study out of Denmark found that patients with BMI indexes in the overweight and moderately obese categories who had been admitted to an ICU for heart failure did not have higher mortality rates than regular-weight patients and actually fared better than underweight ones. Possible explanations for the counterintuitive results are that often being underweight is an indicator of deteriorating health and that fat people's nutritional reserve helps them better cope with life-threatening illness.
In the midst of such ambiguity, one constant remains—our national obsession with dieting and weight loss, despite unambiguous evidence that dieting simply does not work. In 2007 a group of psychology students led by then UCLA professor
Traci Mann looked at how successful dieters were at keeping weight off; the answer was not at all. Mann’s review analyzed 31 long-term studies involving tens of thousands of dieters. One of the studies in Mann's review found that 83 percent of dieters had gained all the weight back in two years, which was typical of the papers Mann reviewed. After five years only rare statistical outliers kept off the weight they had lost. "It doesn't matter what diet you go on," Mann says. "They all work for a little while, and then they fail."
Experts agree that the primary reason for that failure is our fat-laced society. With so much access to so much fatty food, people find it almost impossible to manage obesity without professional help, according to Dr. Arya Sharma, the chair of Obesity Research and Management at the University of Alberta. But most people do not have access to long-term help and try instead—over and over again—to lose in months what took years to gain. This becomes yo-yo dieting, or weight cycling, which has been shown to adversely affect health and even increase the mortality rates of obese people who lost weight compared with their weight-stable peers. "A lot of our weight-loss recommendations are unethical because we shouldn't be saying lose weight when there is no chance people will keep it off," says Sharma.
Still, institutions like the CDC see weight loss as an attainable goal. The CDC's LEAN Works site touts "promising practices . . . strategies delivered to employees through their employer which demonstrate a reduction in a weight-related outcome (i.e., weight, BMI, body fat, waist circumference, waist-to-hip ratio) or prevalence of individuals who are overweight or obese." An example of a "promising practice" is "weight-loss competitions." A data-rich study from Cornell University, which looked at the CDC's proposed remedy for obesity—"workplace obesity-prevention programs"—showed that these programs are rarely successful, and most often simply do not work. As the study's author, economist John Cawley, says, "This intervention is less effective than getting people off heroin."
The problem with dieting is that it is focuses on the elusive goal of weight loss. A promising new approach—dubbed Healthy at Every Size (HAES)—shifts the emphasis from body weight to overall health. Beginning in 2005, Linda Bacon, a Ph.D. in physiology from UC Davis, spent two years conducting research on two groups of obese women. One group followed a standard diet in which participants limited their food intake and were taught how to count fat grams and calories. The other group received training in the tenets of HAES. The HAES group learned how to disentangle their sense of self-worth from their weight, and to eat according to internal body cues. They were instructed on what certain foods did for their well-being, not their weight, and were encouraged to find physical activities that they felt comfortable doing.
Nearly half of the traditional dieters dropped out early, while 92 percent of the HAES group completed the program. The HAES group maintained their body weight through 24 months. The diet group's average weight went down initially, but returned to prestudy levels. Most important, while systolic blood pressure and LDL cholesterol went down for both groups during the study period, the HAES group maintained those lower numbers in tests after the program had ended, suggesting that they were further along in the goal of better health than the women who had lost weight, only to gain it back.
"Dropping the pursuit of weight loss isn't about giving up," Bacon writes in her book, Health at Every Size: The Surprising Truth About Your Weight. "It's about moving on. When you make choices because they help you feel better, not because of their presumed effect on your weight, you maintain them over the long run."
Americans are fatter than ever, and that isn't healthy. But hyping an obesity epidemic and stigmatizing people with big bellies hasn't made us any thinner and doesn't appear to have gotten us any healthier. The sooner we learn to look past the fat and to focus on health, the sooner we will be able to effectively combat all the obesity-linked ailments we fear so much.