If people had more information about the carbon footprint generated by the food they eat, would they make different decisions when ordering in restaurants?

About a third of all man-made greenhouse gas emissions are produced by the global food system—and some restaurants have begun taking steps to mitigate their climate impact by providing customers with information about the emissions associated with specific menu items.

While these labels successfully influence consumers' choices, they can also have unintended consequences, according to new research from Colorado State University's College of Business and colleagues at the University of Arkansas. The research was a result of Garrett Rybak's dissertation on the topic.

The marketing department's Chris Berry and his co-authors examined consumers' reactions to three different menu labels that restaurants could use to show the carbon dioxide equivalent (CO₂e) emissions required to produce a particular meal.

Their research, which was recently published in a special issue on climate change in Journal of the Association for Consumer Research, is among the first to address CO₂e emissions labeling from a marketing perspective. Berry and his co-authors were able to apply the same conceptual frameworks that have been used for decades in nutrition labeling research to find ways that we can reduce our carbon dioxide emissions.

Berry hopes it will serve as a foundation for future research that will help us fight climate change.

"We're beginning to see a number of papers looking at different ways consumers can make more environmentally friendly decisions across contexts," he said. "This area is just beginning to take off—and, I hope, gaining traction in our field."

Adding CO₂e labels to menus works, research shows

To determine how consumers respond to receiving information about their food's carbon footprint, Berry and his co-authors conducted two studies using three types of menu labels.

The first menu label simply presents the numeric information about each menu item's carbon footprint. The second flags items that are below a specific emission threshold, such as the "Cool Foods Meals" menu program developed by the World Resources Institute and recently implemented by Panera Bread. The third option uses stop signs on the menu to indicate which foods have high emissions.

"The numeric information works in the appropriate directions, so that's good," Berry said. The potential unintended consequence arises with the "Cool Foods Meals" option, which the researchers found could lead consumers to incorrect conclusions.

"If you have an item that's just above the threshold and then an item that's just under the threshold, then what a number of consumers are doing is they're choosing the item that's just under the threshold—so, the one with the 'Cool Foods' menu icon," Berry said.

If two menu items are very similar in their environmental impact, but one is eligible for the icon and the other isn't, the icon could be driving perceptions in an unhelpful direction. While consumers should be focused on the value of ordering a salad instead of a hamburger, for example, they might be stuck debating various types of salads.

Ultimately, all three types of labels were found to have potential benefits to consumers when compared with control groups that had no information, but adding numeric information about a meal's CO₂e emissions to a restaurant's menu may be the most objective and least likely to mislead consumers, the studies show.

The research also found that the presence of menu labels could lead consumers to view the restaurant more positively.

"Even in the presence of that stop sign warning, they're actually perceiving the restaurant to be more concerned about the environment," Berry said.

Building on decades of nutrition labeling research

Berry has spent much of his career examining consumers' responses to food labeling and nutrition disclosures, from calorie labeling on menus to health warnings in advertisements for tobacco products.

"I'm applying my expertise on disclosures and health communications to an environmental sustainability context, which, personally, I feel is extremely important as we combat climate change," Berry said.

Although CO₂e emissions labeling can in some ways be compared to familiar practices such as adding calorie counts to menus, there's one crucial difference: Calorie labeling became mandatory for many restaurants in 2018, but CO₂ emissions labeling is unregulated and completely voluntary.

"There's no mandate—there's not even self-regulation around this yet—which provides the opportunity to look at potential avenues for disclosure," Berry said.

Finding ways to encourage consumers to make climate-conscious food decisions is just one way that we can combat climate change, he said. Consumers should be more aware of how the decisions they make every day could affect the environment, from selecting what to have for lunch to choosing how to commute to work.

"In my opinion, this is just one piece of the puzzle—an important piece, but one piece of the puzzle in fighting climate change," Berry said. "I hope that this motivates additional research thinking about CO₂e communications and disclosures in other contexts as well."