A recent study examining the potential impact of sin taxes—increasing the cost of junk food, in particular—as a means to promote healthier choices found that, in a lab setting at least, when unhealthy foods cost more, people tended to eat them less. Now, new research attempts to size up the value of sin taxes in the real world. A study published this week in the Archives of Internal Medicine followed more than 5,000 people from 1985-1986 to 2005-2006, tracking food consumption habits, as well as height, weight and blood sugar levels. They then compared that data with information about food costs across the 20-year period. Researchers found that, incremental increases in price of unhealthy foods resulted in incremental decreases in consumption. In other words, when junk food cost more, people ate it less.
Analyzing the cost of soda and delivery pizza in terms of adjusted 2006 dollars, the researchers found that, during the 20-year study period, pizza and soda costs actually went down—making them more accessible for less. Yet, their analysis also showed that every 10% increase in cost was associated with a decrease in calorie consumption—7% for soda, and 11.5% for pizza. What’s more, a $1 increase in soda price was associated with lower daily caloric intake (about 124 calories less per day on average), lower body weight (2.2 lbs. less, on average) and better blood sugar levels, according to the researchers. Similar trends were seen for a $1 hike in pizza cost, and when both pizza and soda costs increased by $1, the effects were further amplified, the researchers found.
Along with colleagues, lead author Kiyah J. Duffey, from the Department of Nutrition at the University of North Carolina, Chapel Hill, points to the results as possible evidence supporting the use of taxes as a means to promote healthier eating habits. Duffey and co-authors suggest that, based on these findings, an 18% surcharge on soda and delivery pizza could, on average, cut 56 calories per person per day—a reduction that means dropping five pounds per person during the course of a year.
In an accompanying editorial in the Archives of Internal Medicine, Drs. Mitchell Katz and Rajiv Bhatia of the San Francisco Department of Public Health argue that it’s time to put these proposed policies into practice to combat obesity. They suggest that taxes on unhealthy foods could go toward promoting healthier behaviors. Katz and Bhatia write: “Copying a successful tactic of anti-tobacco crusaders, the funds also could be used to counter the lavish advertising of soda and junk food or for ‘marketing’ ordinary tap water.”
The study and accompanying editorial come the same week that Bill Clinton announced the result of a three-year study finding that large beverage companies are voluntarily reducing the sales of sugary sodas in schools, and New York politicians are again bandying about the possibility of a soda tax. And all of these developments add to the already heated debate over the merits of enforcing public health mandates through taxes, of course. Yet, while sin taxes are already widespread across the U.S. in the form of cigarette surcharges—Washington state just tacked another $1 in taxes onto a pack of cigarettes, for example—for many, the growing efforts to govern food choices through tariffs go too far.
What do you think? Are junk food taxes good public health policy? Or are they indicative of a dangerous trend toward government interference in our freedom of choice—”punishing people for enjoying life once in a while,” as one detractor put it?
