First, it was Mayor Michael Bloomberg telling New Yorkers what's good for them by banning large sodas. Is a Bloomberg-style schoolmarm mentality now coming to the nation's capital?
A formal proposal has yet to be introduced, but people living and working in the city should keep an eye on D.C. Council members who have said they would like to have a New York City-style ban on large sugary drinks. As experience shows, bans and taxes in this vein do little or nothing to alter consumer behavior, and stretch the definition of government's legitimate role.
At a recent debate, Councilmen Michael Brown and Vincent Orange said they supported limiting the size of sugary drinks in D.C., along the lines of the measure adopted in New York City this year. Councilwoman Mary Cheh also supported the idea. Lawmakers who promote such "nudging" policies argue that they're not taking away choices, but merely shaping consumers' "choice environment." After all, obesity is a crisis and everyone knows soda is a major cause, right?
Not exactly. There is no consensus among researchers about the link between soda consumption and obesity. Many studies have come out asserting a strong link between sugary beverages and weight gain, whereas others have shown either a weak link or no link at all.
How can studies come to such different conclusions? One likely explanation is the evidence of bias in obesity research. In their 2010 meta-analysis looking at hundreds of publications on obesity research in the last decade, David Allison and Mark Cope of the Biostatistics Department and Nutrition Obesity Research Center at the University of Alabama found disturbing levels of bias and coined the term "white hat bias" to describe the tendency among researchers to distort data in order to advance what they consider a good cause.
Scientists disagree on how much impact soda has on our weight, but it doesn't take a Ph.D. in nutrition to realize that consuming several hundred extra calories a day will lead to weight gain. Despite this, some people choose to drink a liter of soda a day. Will a limit on the size of soda stop them? Going by past experience with such attempts at "nudging" people toward the right choices, it's not likely.
For example, a 2011 University of Illinois study determined that banning the sale of sugary drinks at middle schools only reduced students' access to sugary beverages on campus, but didn't alter their overall consumption of such drinks. In another study of how government policies might alter soda consumption, a research team at Cornell University applied a soda tax to half of a small town. In the first month, soda consumption did decrease, but beer sales increased. After three months, soda consumption was back to its previous level.
Proposals like this are generally based on the underlying assumptions that sugar is bad in any measure, and consumers are too misinformed or weak-willed to make the "right" choice, so therefore politicians have the right and responsibility to make those choices for us.
A limit on big sodas may seem like a small thing, but if we let government limit the size of soda, where does it end? What happens when lawmakers decide to go after fattening foods like white bread, eggs, bacon or cheese? Any of these things, if consumed in outrageous amounts, can lead to negative health effects. Should the government be allowed to limit how much, when and where we can buy these items, "for our own good"?
Michelle Minton is a fellow in consumer policy studies for the Competitive Enterprise Institute.