The Food Journal and Food, Nutrition & Science

An alliance between The Lempert Report and The Center for Food Integrity

Do Junk-Food Taxes Work?

Do Junk-Food Taxes Work?

Health and Wellness

March 27, 2011

Posting calorie counts to change purchasing behaviors may not work, and may actually backfire in some consumers, according to a recent report from researchers at Maastricht University and New Mexico State University and published in the American Journal of Clinical Nutrition. The report looked at imposing junk-food taxes and posting calorie counts as strategies for combating obesity.

Researchers talked to 178 university students and asked them three times to choose from a list of hypothetical lunch items, of which the high-fat choices had varying prices. Some participants were also provided with calorie information; others were not. In addition, those interviewed were categorized as either restrained or unrestrained eaters. Restrained eaters were those that regularly limited their caloric intake.

Participants were given either $10 or $20 and asked not to exceed those amounts in their lunch purchases during the three times they were asked to do so. The first time, the prices on the menu were based on the prices of the school cafeteria. The second time, prices for high-calorie products were raised to 125% of the base price, and the third time, prices were raised to 150% of the base price. This study did not include actual calorie consumption – only potential calorie purchases.

While researchers thought they would find an inverse relationship between price and caloric intake, they learned that this association was rather complex and dependant on other factors – i.e. if caloric information was provided and if the consumer was a restrained or unrestrained eater. When faced with a junk-food tax, unrestrained eaters decreased their caloric intake, regardless of if caloric information was provided or not. On the other hand, pricier foods only dissuaded restrained eaters when caloric intake was not provided.

“Our results suggest that if one wants to help people in general to prevent caloric overconsumption then imposing a high tax on high energy dense food items is much more efficacious than providing calorie-information,” says Dr. Janneke Giesen, Faculty of Psychology and Neuroscience at Maastricht University and a study co-author.

As expected, the food tax did reduce the amount of calories people bought, but this effect was limited to consumers that did not receive calorie information. Interestingly, the food tax effect existed regardless of the amount of money a participant had to spend, even though those with $20 to spend purchased more calories than those with $10 to spend.

Still, the results also suggest that people will not substitute the purchase of expensive high-calorie foods for cheaper low-calorie foods based on price alone. In the case of the restrained eater, they may continue to buy a product as long as they can afford it. A restrained eater provided with caloric information will make the necessary adjustments in their caloric intake and adjust the energy content of their lunch, regardless of taxes inflicted.

Dr. Collin R. Payne, Assistant Professor of Marketing at New Mexico State University and a study co-author, says that this study speaks to the problem of a "one-size-fits-all" policy strategy. That is, in this study, it took a tax of over 25% to change potential calorie purchases significantly, but that tax increase didn't change potential calorie purchasing for those who are most sensitive to calorie consumption and who received calorie information. In other words, for those who would most benefit from a food tax and calorie information, it didn't help.

Payne continues, “The benefit of caloric posting may be simply that the company posting calories may be seen as more transparent and less likely to trick consumers into purchasing their food. The drawback, as seen in this study, is it is difficult to predict how multiple policy measures interact, sometimes leading to less health food consumption, and sometimes leading to more.”

Giesen says that it’s possible that a large junk food tax could work in combating obesity. It is not clear, though, whether a smaller tax, which is perhaps politically more viable, would help in decreasing obesity rates too – or if it could potentially backfire. More research is needed to determine the relationship of lower taxes on food purchasing choices. The relationship between caloric information and taxing should be further examined as well.

“As noted by Dr. Loewenstein in the editorial, ‘Confronting reality: Pitfalls of Calorie Posting,’ in the same issue of the American Journal of Clinical Nutrition as our paper, it could be possible that for some people calorie posting may actually increase caloric intake, as in the case of low-income individuals who try to get the most calories for their money,” says Giesen. “Of course this needs to be tested first before we can conclude if this is really the case.” 

Payne adds that, for their part, retailers could pair with academic researchers to understand – for their target market – what combination of tools would lead to the best possible health outcome for their shoppers. Shoppers could then be provided with informational surveys that provide them with what is known about labeling and taxing foods, and would allow them to better accomplish their goals in the supermarket.

“The benefit of a junk-food tax is decreasing less nutritious food consumption and raising public funds to help defer health costs related to obesity and obesity related diseases associated with their over-consumption,” says Payne. “However, junk-food taxes – at a minimum level – may only stimulate demand, and – at a maximum level – reduce consumption at the expense of the food industry and result in concerns about consumer freedom of choice.”