Public health officials grappling with the obesity epidemic have debated a wide range of approaches to helping slim the American waistline. To some degree, everything from building more sidewalks to banning chocolate milk has been explored. Yet few tactics have been as polarizing as the possibility of introducing tariffs on treats. Despite endorsement from several respected obesity researchers and politicians, soda taxes, for example, have been subject to severe scrutiny, as critics protested that implementing a tax before verifying that it would achieve the end result was shortsighted and potentially overreaching. So, in attempt to determine just how sin taxes might impact people’s food choices, psychologists from the University of Buffalo decided to put junk food levies to the test—in the lab.
Researchers recruited shoppers to peruse the aisles of a mock supermarket filled with 68 common foods labeled with nutritional information. Participants were given a predetermined amount of cash, and were told to use that money to purchase a week’s worth of groceries for a family. The first time, all of the products on the shelves were priced in keeping with local supermarkets. In subsequent trips, however, junk food was taxed—an additional 12.5%, then 25%— or healthier foods were subsidized to reduce cost.
The study, published in the journal Psychological Science revealed that taxes were more effective at getting people to avoid certain products than subsidies were at prompting healthier food purchases. In scenarios where junk foods were taxed, study participants generally came away with a lower caloric total for their groceries, and a higher ratio of protein to fats and carbohydrates. Yet, in situations where healthy foods were subsidized, the savings were often spent on additional junk food. That is, instead of stocking up on more fruits and vegetables because they were cheaper, the study’s shoppers bought their veggies, and then used the leftover cash to bring home extra treats like chips and soda. In the end, the subsidies-only scenarios resulted in higher total calorie counts, and didn’t result in overall nutritional improvement on the week’s groceries.
Because the scenario is hypothetical, the findings certainly shouldn’t be taken as the final word in the sin tax debate, the researchers stress, but should instead be used to inform the ongoing discussion about practical ways to battle obesity. To that end, they say, the next step should be research to determine whether these results would be replicated in the real world.