Should restaurants put carbon footprint labels on their menus?

The food and beverage industry—a major supply chain that encompasses farming, processing, and food distribution practices—is part of the global food production system, which is currently responsible for around 26 percent of the world’s greenhouse gas (GHG) emissions. The United States has the largest food and beverage industry in the world and is also the largest market for eating out in restaurants and cafes based on consumer spending.

For restaurant owners, this is a huge opportunity to push for sustainable eating. New research seems to suggest that it’s possible for restaurants to move their customers toward low-emissions eating through menu design reconfigurations.

Putting carbon labels on menus and switching defaults may reduce carbon emissions

A recent study published in PLOS Climate found that the design of restaurant menus is capable of influencing customers’ dish choices. Make those dish choices more climate-friendly, and there’s a chance for a reduction in the carbon footprint of the meal. 

The authors created various menus for nine different hypothetical restaurants while employing two different interventions: indicating the amount of GHG emissions of each dish (also known as the carbon label) and putting lower-emission dish choices as the default menu option. The carbon labels also had a stoplight-colored signal to indicate the degree of GHG emissions, which meant that red was used for high-emission, yellow for medium-emission, and green for low-emission dishes.

About 265 participants—the majority of whom were German residents—chose dishes online after viewing nine menus. Each of the nine menus had two types: one with carbon labels and one without. Three menus were unitary, offering dishes that were either high-, medium-, or low-emission. Meanwhile, six menus were modular, which meant that every dish had a high-, medium- or low-emission option. The modular menus either had no default option or have either red or green dishes as the default.

Based on the experiments, participants reduced the choice of red dishes when carbon labels were present and the defaults were switched, like making the veggie burger the standard instead of the beef burger, says author Benedikt Seger, postdoctoral research scientist in the department of Developmental Psychology at the University of Würzburg. It also increased the decision to munch on green dishes to a limited extent.

“The default switches were associated with a reduction of 300 to 500 grams of CO2 equivalent, depending on whether we compare them to menus without any defaults or menus where the ‘red’ dish was the default,” says Seger. Meanwhile, the carbon labels were associated with an average reduction of 200 grams of CO2 equivalent, he adds.

Conducting the experiments online was one of the limitations of the study since real restaurant settings would have more influence on customers’ dish choices, such as the order of other guests. “We would expect that the CO2 reduction effect of carbon labels and default switches would be lower [in real restaurants] than in our online study,” says Seger. 

The overall design of the menu must be considered

Although the study showed promising results, carbon labels may not be effective if customers don’t look at them in the first place. A 2019 study published in the Journal of Sustainable Tourism found that carbon labels on restaurant menus are not enough to influence customers to order low-emission dish choices because customers don’t always pay attention to the labels.

“We measured their eye movements, so we know exactly how much attention they paid to [the carbon labels],” says author of the 2019 paper Sara Dolnicar, social scientist at The University of Queensland, Australia. “People are fascinated when they first see them, but then focus on the food, not the emissions.” According to their findings, the participants only spent about 5 percent of their time looking at carbon labels, which indicates that it doesn’t play a big role in their dish choices. However, there are a few consumers who do care about the carbon labels, she adds.

But the two studies had a big difference in menus—the decision to include food photos or not.

The carbon labels in the 2019 study did not grab the participants’ attention because the menus included colored pictures of the dishes, argues Seger. This has implications for other informative menu elements as well, such as health, organic, and veggie labels. “The more such labels we include, the less potential each of them has to change customers’ behavior, because attention is a limited resource,” he adds.

There are various explanations as to why the menu design interventions in the 2022 study worked. For instance, having a stoplight-colored scale helps because green labels are more socially approved than red ones, says Seger. Moreover, switching the defaults and making low-emission dishes the standard can be effective because default choices function as recommendations, which tell the customer that it is “normal” or “usual,” he adds.

The challenge is to find a balance of reducing emissions without upsetting customers, says Dolnicar. “Defaults are always the most powerful option,” she adds. “The best default, of course, is to just sell vegetarian dishes, but gentler nudges could help also.” Rearranging the order of the meals on the menu, or having a low-emissions menu as the default and providing a conventional menu only upon request, may be beneficial. 

The best part of these changes for restauranteurs is that they don’t require changes to the food that they offer and may even encourage other restaurants to follow suit, says Seger. In the long run, customers may also change their habitual dining behavior, he adds.

“To put it simply, we need to cut carbon emissions in every sphere of life,” says Seger. “So why should dining make an exception?”