The Sugar Wars: Science’s Fierce, Geeky Debate Over Soda
October 16, 2012
The debating season may be presidential, but if the spectacle of supersized pandering served with an unlimited salad bar of platitudes, slogans, and empty promises strikes you as strangely unfulfilling, there is always academia, where, sometimes, the politics are as equally vicious because the stakes are equally as high. Such was the case in San Antonio recently, at the Obesity Society’s 30th annual meeting, the premier scientific conference in the US on what is, arguably, the nation’s most pressing health problem. As the prologue to a four-day Finnegan’s Wake of technical discussion (did you know that NMDA receptor NR2B subunits in the parabrachial nucleus mediate compensatory feeding?), the society’s presidential keynote debate took a simpler route: let’s argue about soda. The result was mesmerizing, a data maven’s idea of good night out. Two academic foes garlanded with paragraph-length job titles, and trailing hundreds of papers in published research, hurled power point slides filled with p-values and confidence intervals at each other with relentless Titanic geekiness. The audience— a large sample of the best and brightest in obesity research, and those who aspired to join them—squinted to keep up.
There were jokes too, although not many given the amount of charts, and numbers and citations that had to be crammed into a fleeting hour or so of combative colloquy. Dr. Frank Hu, Professor of Nutrition and Epidemiology at Harvard’s School of Public Health, started his assault on soda with a slide of Clint Eastwood debating an empty chair, the dominant image from the summer’s Republican national convention. Given that this opponent, Dr. David Allison, Distinguished Professor and Director of the National Institutes for Health-funded Nutrition Obesity Research Center at the University of Alabama at Birmingham, was such a “formidable debater,” Hu said, he would rather be debating Eastwood’s chair, perhaps with some soda bottles sitting on it. Through the magic of PowerPoint, three soda bottles appeared on the chair. The audience laughed. “If I debate that chair,” said Hu, “I think I’m going to win.” Allison, in turn, made a Dr. Who joke, giving away his age with a picture of Tom Baker, last seen saving the universe against cheaply made balsa wood and plastic BBC aliens in 1981. But that, in a peculiar way, was symbolic. The kids of the 70s had been nourished on cheaply made, weirdly pleasurable, possibly unnatural calories; but their bodies did not turn out to be like Doctor Who’s Tardis, a telephone box that expanded on the inside while remaining svelte and fixed in its external dimensions.
Was it the soda, the sugar, the deluge of so-called empty calories that had made us so fat? Or was this no more than the academic equivalent of junk food, emotionally and politically satisfying yet intellectually empty?
Certainly, there’s something intuitive to the idea that “Big Gulps” had an asteroid-like effect on the evolution of our girth. In that sense, Hu had the seemingly easy task of indicting soda—or sugar-sweetened beverages (SSBs), to be technically precise and inclusive—as the “plague rat” in the obesity epidemic, arguing for the motion that there is sufficient evidence that decreasing SSBs would reduce the prevalence of obesity and obesity-related diseases. This line of argument has been an increasingly common theme in the media, with activist groups such as the Center for Science in the Public Interest (the group that once denounced fettuccine alfredo as “a heart attack on a plate”), politicians such as New York’s Mayor Bloomberg, and academics, such as Yale’s Kelly Brownell, repeatedly calling for the government to regulate soda to reduce obesity—and, in the case of Bloomberg, actually doing so through regulating soda serving sizes. It’s a tempting scenario: much as one might gut the worldwide prevalence of lung cancer by targeting tobacco, one might arrest and reverse ballooning obesity trends by indicting sugared drinks.
But things are not quite as simple as a media meme or a political trend, otherwise why would the Obesity Society stage such a debate or, indeed, an entire conference wherein soda was, at best, a minor player in a complex drama of cause and effect? To go from room to room at the Henry B. Gonzalez Conference Center was to go from probable cause to possible cause and back again. Sleep loss? Yes, the “epidemic” of sleep loss in America shadows the epidemic in obesity. Circadian rhythm? The timing of your meal may disrupt not only your body’s internal clock, which ticks in every tissue, but also the circadian rhythms of the bacteria in your gut. Genetics? Obese mothers have underweight children, which is the key factor in predicting their children’s later obesity. Food stress, as mothers wean, can permanently alter the growing brain though it may last only a few days—at least in Macaque monkeys. Using heavier crockery to plate your food can, if you feel the weight, change your perception of how much food you think you’ll need to eat. And these are but morsels from the conference menu.
As Mike Gibney, Professor of Food and Health at University College Dublin, recently noted, if we think of heart disease as having a complexity of one, and cancer a complexity of ten, then obesity has a complexity of 100. Which means, he continued, that anyone who argues that one food alone is behind the obesity epidemic is just not being intellectually serious.
Moreover, as the economic historian John Komlos has pointed out, it’s a mistake to think that obesity suddenly arrived in America as a problem in the 1980s. If you looked at historical data for Body Mass Index (BMI—a proxy measure for fat), Americans started putting on the pounds in the 1920s and piling them on in the 50s and 60s. It just looked like the obesity epidemic struck in the 80s because that’s when the BMI threshold for defining obesity was crossed by a mass of people who had been gradually putting on the pounds year after year. This, in turn, coincided with the Centers for Disease Control beginning to systematically measure it. All of which meant that while the Dr.Who-loving Allison had the seemingly hopeless task of arguing that the evidence wasn’t sufficient to indict soda, it was far from clear that Harvard, a powerhouse public health school, was about to score an easy victory over Alabama, a powerhouse obesity research center—at least in front of this audience of experts…