It’s Not Just Genetics. It’s easy to forget that social factors play a significant role in America’s epidemic of childhood obesity. The tide of obesity discriminates by race: according to the Centers for Disease Control and Protection’s 2006 figures, 30.7% of white American kids are overweight or obese, compared with 34.9% of blacks and 38% of Mexican Americans. It discriminates by income: 22.4% of 10-to-17-year-olds living below the poverty line—less than US$21,200 for a family of four—are overweight or obese, compared with 9.1% of kids whose families earn at least four times that amount. It discriminates, perhaps most tellingly, by geography, with 16.5% of rural kids qualifying as obese, compared with 14.4% of urban kids, according to the 2003 National Survey of Children’s Health. The poorest states of the South and Appalachia—Arkansas, West Virginia, Mississippi, and Kentucky—have the heaviest children. Adult obesity levels triple when you cross north of 96th Street in Manhattan, leaving the mostly white and well-off Upper East Side for the predominantly minority, poorer neighborhood of Spanish Harlem. Even in trim Colorado, there are obesity hot zones.
All that provides a new way to look at—and attack— obesity. We tend not to talk about a problem like body weight in the language of infectious disease, but scientists do, knowing that like any other epidemic, the US’s obesity scourge hits some communities harder than others. The skyrocketing increase in childhood obesity—the percentage of 6-to-11-year-olds classified as obese has nearly tripled since 1980—may argue strongly that the American environment has changed in a way that makes gaining weight much less avoidable. But the uneven distribution of the problem argues that who you are, where you are, and how much your family has in the bank have a lotto do with whether your child will be claimed by the crisis or emerge unharmed.
“The environment makes it easier or harder for healthy choices to be the default choices,” says Risa Lavizzo-Mourey, president of the Robert Wood Johnson Foundation, which lastyear pledged US$500 million to end the rise in childhood obesity by 2015. “And adults create the environment that kids live in.” The geography of childhood obesity is largely the geography of poverty. There’s no pretending that the problem—and resultant disparities in income, education, and opportunity—will be easy to address, but there’s no denying that it’s imperative that we try. “It’s the poorest and most deprived neighborhoods that suffer the most,” says Adam Drewnowski, director of the nutritional-science program at the University of Washington. “This has to be fixed.”
The federal government, meanwhile, has dropped the ball when it comes to obesity. Seven years ago, Congress allocated US$125 million for a smart new health campaign, dubbed Verb, aimed at getting pre-teen kids to become more active. Boldface names such as teen star Miley Cyrus and quarterback Donovan McNabb headlined public-service ads, and volunteers set up booths at public events. In the program’s firstyear, up to 80% of kids polled were aware of the Verb message, and communities began sponsoring their own Verb-based activities. But that success could not survive congressional budget cuts, and the program’s funding was steadily slashed. By 2007, funds were shut off altogether, and Verb was past tense.
The government insists that the decision was a fiscally prudent one and that local and state programs, like the widely publicized fitness initiatives launched by California Gov. Arnold Schwarzenegger or the less publicized INShape program begun in 2005 by Indiana Gov. Mitch Daniels, are a more efficient way to get the message out. “Obesity is not the kind of problem that is going to respond to just the flow of federal funds,” says Galson. The fact is, however, that in the case of Verb, responding was precisely what it was doing—even if only a little.
Looking Ahead. In all of this, there are flickers of hope. In May 2008, epidemiologists were thrilled when the Journal of the American Medical Association published a study of 8,165 children, which showed that for the first time in decades, the increase in US childhood obesity had leveled off. It’s not certain if the plateau is a sign that public-awareness programs and improved menus in many school cafeterias are producing results or merely that some kind of saturation point has been reached, with most kids genetically susceptible to gaining too much weight having done so. “Whether this is meaningful data, we don’t know yet,” says Seeley. “But anyone who wants to stick a flag in this and declare victory is just crazy.”
Clearly, nobody is going that far. Victory may indeed come, but it will be only after a long, multifront war, one that is at last being joined. Parents are fighting it in the home as they learn how to make healthier meals available to their families, set better examples with their own food choices, and manage the critical issues of self-esteem that can be so disabling for overweight kids.
Policy makers are fighting it as they study the growing body of research showing how everything from income to race to education plays a role in how much kids weigh and as they craft local solutions to solve these local problems.
Doctors are fighting it as they deal daily with the ills associated with childhood obesity and work to repair the damage that’s been done. And perhaps most important, teachers, mentors, and public role models are fighting it as they help kids navigate a culture that fosters fat but idealizes thin and as they teach them that what truly counts is getting themselves as fit as their body type and genes allow—and then loving that body no matter what.
Do all these things—and do them right—and the national obesity epidemic just might be brought under control before some kids struggling with their weight today even reach middle age. “If we got this way over the last 30 years,” says Galson, “it’s not going to take us centuries to get back. We could reverse things at the same speed or even faster.” Americans will continue to love good food; the trick will be to learn to love good health even more.
The measurement of time is an ancient science.
The Cro-Magnons recorded the phases of the Moon some 30,000 years ago—but the first minutes were counted accurately only 400 years ago, and the atomic clocks that allow us to track time to the billionth of a second are less than 50 years old. Timekeeping has been both a lens through which humanity has observed the heavens and a mirror reflecting the progress of science and civilization. Our millennia-long struggle to define and calibrate time through calendars and clocks has meant trying to bring the register of human affairs in line with natural cycles—of the Earth, Sun, Moon, and stars, of the physics of matter—but always cycles. What vary are the cultural values and goals that dictate which cycles are significant.
With a religious culture dominated by gods of the Sun and sky and a civilization dependent on the annual cycle of a river, the ancient Egyptians were expert astronomers who studied the Sun’s recurrent movements and their effects on the Earth very closely. By plotting the beginning of the Nile’s flood each year, a reliable harbinger of seasonal change, they measured a cycle 365 days long—a reasonable approximation of the duration of the solar year. Observations of the star Sirius eventually allowed Egyptian astronomers to adjust the solar year to 365.25 days. Astronomic studies by the Mayan civilization of the first millennium ad underlay a complex calendrical system involving an accurately determined solar year (18 months of days, plus an unlucky 5-day period) and a sacred year of 260 days (13 cycles of 20 named days).
About 127 bc the Greek astronomer Hipparchus further refined the year. His adjustments centered on the equinoxes—which he discovered to be shifting to the west at the barely perceptible rate of two degrees in 150 years. Because of this discovery, Hipparchus realized that the solar year was slightly shorter than the accepted 365.25 days. His calculation of 365.242 days was remarkably close to the present calculation of 365.242199 days.
Unfortunately for people of the next 1,600 years, Hipparchus’s discoveries were virtually ignored by calendar makers. Julius Caesar’s calendrical reforms in 46 bc left the calendar year at 365.25 days—more than 11 minutes too long. By the 1500s the Julian calendar was 10 days behind the solar year. The shortfall alarmed Christian religious leaders because it meant that holy days, including Easter, were being observed at the wrong times. In 1582 Pope Gregory XIII officially revised the accepted length of the year to 365.2422 days, adjusted the leap-year rule, and lopped off the 10 extra days, creating in the process the calendar in most widespread use today.
Meanwhile, the quest to measure time accurately on a much smaller scale was still in its early phases. The invention of the weight-driven mechanical clock some 200 years earlier had revolutionized timekeeping, making it possible to count equal units of time and radically changing the way people thought about time and the best ways to measure it.
Calendars are deemed accurate according to how well they accommodate the variations in larger celestial cycles. Clocks, on the other hand, have historically been judged accurate in relation to the average duration of the Earth’s rotation around the Sun—that is, by how well they keep “mean time.” While calendrical standards have remained fairly stable, the clock’s units of measure have gradually shifted away from using the Earth-Sun relationship as a norm. With the introduction of mechanical clocks, clock time became increasingly removed from cyclical events in the sky, for the cycles on which mechanical clocks base their measures are independent of Earth and Sun. A pendulum clock, for example, measures only the beat of its pendulum, not any part of a “real” day.
The pendulum clock kicked off the modern search for the perfect clock, a timepiece governed by a naturally cycling period that operated free from mechanical friction and fatigue. In 1927 W.A. Marrison invented a clock that operated via a tiny quartz crystal. The crystal vibrated at an ultrasonic frequency when exposed to an electric field. These vibrations were constant and delivered a virtually frictionless beat to the counting mechanism of the clock. Accurate to thousandths of a second, quartz clocks led scientists to make the belated discovery that the Earth was not a reliable clock to begin with. Disparities between the measurements of quartz clocks and the rotation of the Earth revealed unpredictable irregularities in the rotation, which had to that point defined the duration of a second (1/86,400 of the mean solar day).
In 1967 the definition of a second was officially divorced from the Earth’s rotation when the 13th General Conference of Weights and Measures redefined the second as “9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom.” Cesium atoms are superior to quartz crystals because they do not wear out and have cycles that comprise oscillations between precisely defined energy states that can oscillate forever without any distortion. Furthermore, each atom of cesium oscillates at exactly the same frequency as all others, making each one a perfect timekeeper. To keep solar time and atomic time from drifting too far apart, the two were combined in 1964 to form Coordinated Universal Time, which is based on the atomic second and kept within 0.9 second of solar time by adding a leap second as needed.
