First distributed 1 April 2002 (but not, unfortunately, an April Fool's joke)
Despite claims by anti-sprawl, anti-auto activists, the nation's recent "obesity epidemic" has nothing to do with the suburbs. It is not even certain that there is such an epidemic, since the only evidence for it is unverified telephone surveys whose results differ greatly from actual measurements of American weights.
But given that some Americans are overweight, the available evidence indicates that obesity is found more in the supposedly walkable cities than in the supposedly auto-dependent suburbs. For example, Hispanics and African-Americans, who tend to be concentrated in the cities, are much more likely to be obese than non-Hispanic whites, who tend to live in the suburbs. This suggests that obesity is associated more with low-income levels than with geography.
Studies also indicate that the amount of exercise Americans get has not changed in decades. If obesity is increasing, then, it is due to changes in diet, not to changes in physical activity resulting from too much driving or pedestrian-unfriendly environments.
It is not surprising that anti-sprawl activists would leap onto the anti-fat bandwagon with specious claims that suburbs cause obesity. Public health officials, however, should not delude themselves into thinking that endorsements of the smart-growth planning fad will do anything to reduce obesity or promote health.
The suburbs "encourage sedentary living habits" that have led to an epidemic of obesity, say anti-sprawl public-health officials. Since the "health care burden" of obesity can "conservatively" be estimated to be "more than $100 billion," we need to promote exercise by rebuilding the suburbs into denser, less auto-friendly areas.
These quotes are from page 9 of the study by employees of the Centers for Disease Control (CDC) that was published by the SprawlWatch Clearinghouse. As noted in the Vanishing Automobile Update #22, the report's speculative claims are not supported by any evidence associating obesity with the suburbs or physical fitness with New Urban design.
Since update #22, I have reviewed more data and studies on obesity in America. The basic source for the claim that there is an obesity epidemic is a CDC study concluding that the share of Americans who are obese has increased from 12 percent in 1991 to 18 percent in 1998 and more than 19 percent in 2000.
The CDC defines "obese" as having a body-mass index (BMI) of 30 or more. "Overweight" is a body-mass index of 25 or more. BMI for adults is calculated by dividing a persons weight in kilograms by the square of their height in meters. For those who are not yet metricized, multiply your weight in pounds by 703 and divide by the square of your height in inches. Or use the CDC's BMI calculator, which works in either English or metric units.
Without naming any names, if you are a balding researcher who is 5-feet, 7-inches tall and weigh 159 pounds, your BMI is a marginally satisfactory 24.9. However, if you creep up to 160 pounds, you fall into the overweight category with a BMI of 25.1. This means that our hypothetical researcher probably shouldn't have the Valrhona chocolate mousse that everyone else is enjoying for dessert tonight.
CDC breakdowns of obesity levels by state show some rather alarming trends. In my home state of Oregon, for example, less than 15 percent of adults were considered obese in 1995, but by 2000 more than 20 percent were obese.
Some states were even worse: Georgia obesity rates more than doubled, from less than 10 percent to more than 20 percent, between 1991 and 1999. Obesity increased in every state during that time period, with the greatest increases in the South and Midwest. (CDC has the complete data series.)
Surgeon General David Satcher has called the obesity epidemic a "crisis" because obesity supposedly kills 325,000 Americans a year and adds $117 billion to annual health care costs.
What happened between 1990 and 2000 that would explain this sudden ballooning of the American public? The popular explanation is that people are eating fattier foods and exercising less. However, I can think of three other explanations that make more sense.
First, the explanation for just about every demographic trend in modern America: baby boomers. Perhaps they got older, exercised less, but kept eating. The problem with this is that the CDC claims that the most fattened adult age class is 19- to 29-year-olds. Children are also supposedly getting fatter as well.
The second explanation for increased obesity rates is more compelling: The declining unemployment and rising incomes of the 1990s. Paul Fussell observes in his 1983 book, "Class," obesity is in large part a class phenomenon. One hundred years ago, it was fashionable among the wealthy to have a paunch, and men's clothes were even designed to emphasize one. This is what led to the popular notion of wealthy people as "fat cats."
Today, of course, the middle and upper classes prefer to be fashionably thin, but working class people tend to be overweight. CDC researchers agree that "lower economic status . . . is associated with obesity." Just as weight indicated wealth a century ago, it indicates security today. Perhaps the booming 90s saw unemployment rates at near-record lows, enabling more people to earn enough money to feed their families enough to become overweight.
A close look at the obesity statistics supports this notion. According to CDC data, obesity is growing fastest among Hispanics. CDC data also indicate that the most obese children are African-American girls, 17 percent of whom are overweight compared to less than 12 percent of other groups. A study from the New Jersey University of Medicine finds that 22 percent of Hispanic and black children are likely to be overweight compared with only 12 percent of non-Hispanic white children.
If there is an obesity epidemic, then, it may merely reflect a healthy economy that has provided jobs for low-income people. If so, then one sure cure for the epidemic would be a good, long recession. Policies aimed at such a recession make as much sense as trying to cure congestion by stopping new highway construction and putting barriers in existing roads - which, of course, are the policies recommended by anti-sprawl forces.
The third explanation is that the numbers are simply wrong. They are based on a random telephone survey of people's heights and weights done by state health officials and coordinated by the CDC. Only 21 states participated in the survey in 1985. By 1990, all but 5 (mostly unpopulated) states reported in, and all joined by 1994.
How accurate is a telephone survey? Without naming any specific genders, a lot of people I know won't even tell their husbands how much they weigh, much less a complete stranger calling on the phone. At the same time, people in a completely different gender tend to overstate their height. (Our hypothetical researcher would like everyone to know that he is really 5-feet, 7.5 inches tall, but modestly used 5-feet-7 for the purposes of this article.)
Because so many people understate their weight and/or overstate their height, CDC researchers assume that actual obesity rates are much higher than are revealed by their telephone surveys. Indeed, they point out that real measurements of large numbers of Americans reveal much higher rates of obesity -- 22 percent -- than any of the telephone surveys, which so far have never recorded rates as high as 20 percent.
Thus, the obesity epidemic may really be a truthfulness epidemic. Perhaps interviewers in recent years prodded interviewees a bit harder to get more accurate results. Or perhaps people are more willing to admit they are overweight because so many popular writers blame obesity on McDonalds, Coca-Cola, Frito-Lay, and other food makers rather than the overweight people themselves.
Stephen Milloy, who publishes the junkscience.com web site, calls these numbers "unadulterated junk science" since the data collected by telephone were never verified. Milloy suggests that reports of a fat epidemic are coming from bureaucrats and academic researchers who simply want to expand their budgets and power.
I downloaded data from the suspiciously named Behavioral Risk Factors Surveillance System, an annual poll that the Centers for Disease Control advertise as "the world's largest telephone survey." The CDC and state public health agencies contact close to 200,000 people a year and ask them hundreds of nosy questions about their health and opinions.
The CDC brags that the survey has had major influences on public policy. For example, it says, the survey's finding that most people think second-hand smoke is dangerous convinced the Oregon legislature to ban workplace smoking. Whether second-hand smoke really is dangerous seems to be beside the point.
The CDC posts the data for every year from 1996 through 2000. In zipped, ASCII format, each year's data is about 15 megabytes. Unzipping it increases it to 160 megabytes.
I downloaded data for 2000 and compared body-mass index (BMI) with income, education, and race. Early surveys asked people whether they lived in a single-family home or a multi-family dwelling, but that question was unfortunately dropped in 1995.
The table below shows the average BMI and the percent of people in each category whose BMI is greater than 30 (CDC's definition of obese). For comparison, the average BMI of all the people in the sample (at least, all of those who gave their weights and heights) is 26.4, and 20.4 percent of them are obese.
Household Average Percent Income BMI Obese <10000 27.3 27.5% 10000-14999 27.2 25.7% 15000-19999 26.8 24.0% 20000-24999 26.7 23.1% 25000-34999 26.5 21.1% 35000-49999 26.5 20.8% 50000-74999 26.3 18.6% 75000+ 25.7 15.1%
The data confirms that BMI is clearly correlated with household income: the lower the income, the higher the BMI and the higher the obesity rate.
Average Percent Education BMI Obese None 27.4 25.2% Grade 1-8 27.6 28.3% Grade 9-11 27.2 26.2% Grade 12 26.7 22.3% College 1-3 26.4 20.6% College grad 25.7 15.4%
BMI is also correlated with education: the lower the education, the higher the BMI and the higher the obesity rate. The only exception is the category of people with no education. This is probably heavily stocked with recent immigrants, as 38 percent of this category is Hispanic compared with 8 percent of the total.
Average Percent Race BMI Obese Black 28.2 31.6% Native American 27.8 29.1% Hispanic 26.9 22.7% Other 26.8 22.6% Non-Hispanic White 26.2 19.2% Asian-Pacific 24.3 8.3%
Asians (including Pacific islanders) have the lowest BMIs, followed by non-Hispanic whites, Hispanics, Native Americans, and Blacks. "Other" is somewhere in the middle.
Average Percent Age BMI Obese <30 25.0 14.3% 30 to 39 26.4 20.0% 40 to 49 26.8 22.6% 50 to 59 27.4 25.5% 60 to 69 27.2 24.3% 70 plus 25.8 16.0%
BMI is also correlated with age: BMI's and obesity rates peak in the 50-59 age category and fall with decreasing and increasing age away from that category. This tends to support the baby boomer hypothesis.
Stephen Milloy also cites an editorial from the New England Journal of Medicine questioning the surgeon general's claims that obesity causes 325,000 deaths or more per year -- and, by implication, the claim that the health costs of obesity are more than $100 billion per year. "That figure is by no means well established," says the Journal, adding, "Most of the evidence is either indirect or derived from (studies with) serious methodological flaws."
More than one recent study has found that weight is less important to health as you get older. Our hypothetical researcher, whose 50th birthday is in less than six months, will be reassured to know, for example, that people over 50 can have BMIs as high as 32 and not suffer any greater mortality than people with BMIs under 25. Researchers add that, unless such people have heart disease, diabetes, or some other obesity-related disease, asking them to diet "might unjustifiably decrease their perceived quality of life."
Yet it remains true that some Americans are obese and that severe obesity is associated with heart disease, diabetes, and other health problems. To what extent is that obesity caused by the suburbs?
The detailed data suggest that, if anything, cities are more obese than the suburbs. While many minorities are moving to the suburbs, Hispanics and blacks remain concentrated in cities and the suburbs remain heavily white. It appears that location tends to be less important than income.
The SprawlWatch report still insists that the "built environment" contributes to obesity because it encourages auto driving rather than walking or cycling. But another finding of the CDC telephone survey is that the amount of physical activity Americans undertake has not changed substantially in the last decade.
In fact, says another report, "the activity levels of Americans appear to have changed little, if at all, from the 1970s to the 1990s." This indicates that increased auto driving and the built environment have nothing to do with recent changes in obesity rates.
Despite this finding, the report's authors recommend that "cities, zoning authorities, and urban planners" should "modify zoning requirements, designate downtown areas as pedestrian malls and automobile-free zones, and modify residential neighborhoods, workplaces, and shopping centers to promote physical activity." Among the other recommendations are to "Designate an annual National 'No-TV' Week," restrict advertising on high-calorie foods on children's television, tax high-calorie or high-fat foods, and subsidize low-calorie nutritious foods.
These and twenty-six other recommendations are made with absolutely no assessment of their efficacy. Before elected officials and government bureaucrats start implementing such policies, they should find out whether they will work or whether they will do more harm than good.
Anti-sprawl activists are also quick to note that children today are less likely to walk to school and more likely to have their parents drive them. But this isn't a suburban phenomenon either. Before 1980, 80 percent of American schoolchildren walked to school. By 1990, less than a third did.
Yet 57 percent of American families didn't move to the suburbs during the 1980s. Instead, something else must explain this change.
The answer seems to be milk cartons -- specifically, the "missing children" campaign that crested in the 1980s. This media-generated panic turned out to be phony -- the vast majority of the "kidnapped" children had been taken by one of their family members in a custody dispute. Yet CDC Dr. William Dietz believes that "parental fear about kidnapping" is one of the major reasons why children today get less exercise than they did twenty years ago. (Dietz was quoted on "California Reports," a public radio program aired by California public radio stations on November 30, 2001.)
Eric Schlosser, author of Fast Food Nation, has a different take on the sprawl and obesity. He argues that fast-food restaurants such as McDonalds were "a catalyst" to sprawl. And he also blames those fast-food restaurants for the obesity epidemic, claiming that the price paid for fast food fails to account for the "real price" of the meal, mainly the social cost of obesity.
Schlosser's view is underscored by George Washington University law Professor John Banzhaf, who takes credit for helping "come up with the idea of suing tobacco companies as a way of shifting the cost of smoking from the nonsmokers to the smokers." Now he argues that the oft-cited $100 billion cost of obesity is partly paid "by people who maintain a healthy weight in the form of higher taxes and health insurance." Banzhaf is urging people to sue food companies for imposing those costs on society.
This is a difficult case for lawyers to make because, in contrast to smoking, fatty foods produce no "second-hand fat." It will be hard to prove that a particular food contributed to obesity; that obesity caused a particular health problem; and that that health problem imposes costs on people who don't suffer from it. If seriously obese people don't live as long as thinner people, it is possible that the health costs they impose on society are actually lower, not higher, than average.
So some nutritionists go beyond Banzhaf and advocate suing food companies just for selling people fatty foods. The ironically named Marion Nestle, a nutrition professor at New York University and author of the forthcoming book, "Food Politics: How the Food Industry Manipulates What We Eat to the Detriment of Our Health," observes that "The function of the food industry is to get people to eat more, not less."
"There's a lot of people who benefit from people being fat and sick," Nestle claims elsewhere. "So the response to the food industry should be very similar to what happened with the tobacco companies," meaning that food companies should be sued for making people fat.
This is a common theme of the anti-corporate, pro-government movement: People are so easily manipulated by advertising that they need government regulation to protect them from things they shouldn't do. Anti-fat activists argue, for example, that vending machines should be banned from schools so that students aren't given the opportunity to buy junk food.
Indeed, many food activists want to demonize fatty foods just as tobacco has been demonized. "I want to get to the point where people are in the hallway and see a vending machine and say, 'That's bad, that shouldn't be there,' in the same way as if they saw a cigarette vending machine," says Tom Farley of the Tulane University School of Public Health and Tropical Medicine.
In fact, a Newsday columnist named Meredith Berkman recently filed one of the first anti-fat lawsuits against the manufacturer of a snack food named Pirate's Booty. In December, 2001, the Good Housekeeping Institute tested Pirate's Booty, which is basically flavored puffed rice, and found that it contained three times as much fat as the label stated. The manufacturer, Robert's American Gourmet Foods (a subsidiary of Keystone Foods), blamed the problem on a change in its manufacturing process and immediately recalled the product from store shelves.
Nearly four months after the recall, Berkman filed a $50 million class-action lawsuit against Robert's Foods, claiming "emotional distress" and nutritional damage. The complaint claims to represent all consumers who ruined their diets and hat to spend more time at the gym because they ate mislabeled Pirate's Booty.
Mislabeling of foods is a problem. But in a more general sense can McDonalds hamburgers, Hostess Twinkies, and Haagen-Dazs ice cream be blamed for making people fat?
Michael Pollan takes a different attitude in his recent book, Botany of Desire. Pollan is no friend to the food industry and makes it clear that he opposes genetically manipulated foods. He also notes that refined sugar is a recent phenomenon: A little more than a century ago, few people could afford most sweets.
But he tries to imagine what it was like the first time someone tasted honey or some other sugar. The closest he can come is to recall his one-year-old son's reaction when he tasted his birthday cake - the first time he was treated to a sweet. A look of wonderment came over his face, as if to say, "Why didn't you tell me there was something like this in the world? I am going to dedicate the rest of my life to getting more of it." And, Pollan notes, "he pretty much has."
Pollan's son was too young to be manipulated by advertising or the food industry. The lesson is that diet and physical activity are matters of self discipline (or, in the case of children, parental discipline). Fast-food restaurants and other parts of the food industry sell things that people want, and the industry is subject to enormous selection pressures filtering out things that people don't want. The health-food and weight-loss segments of the industry are each multi-billion dollar industries in their own right.
Some Americans clearly are obese, but this seems to be more of a class phenomenon than one due to advertising or fast food. The evidence that obesity is increasing is highly questionable given that it is based on unverified telephone surveys whose results have yet to agree with actual measurements of large numbers of Americans.
Nor is there any evidence at all that physical activity and healthy weights are influenced by the built environment, as claimed by sprawl opponents. Indeed, obesity seems to be more prevalent in central cities than in the suburbs and it appears to be caused more by eating habits and incomes, not by changes in physical activity or the built environment.