Can restaurant menus help diners choose climate-friendly meals?

Figuring out the right meal to eat when dining out can feel like a herculean task. Is it healthy? Is the price worth the amount of food? Should I risk trying something new or stick with my usual go-to item? But there’s one more important question that you might be overlooking: Is this meal good for the planet?

New research suggests restaurants can help customers pick more climate-friendly options with a lower carbon footprint — fewer greenhouse gas emissions — using a few simple design changes to their menus. The findings were published Wednesday in the journal PLOS Climate.

“Our study suggests that people are willing to consider the climate crisis in their dish choices,” Benedikt Seger, lead author of the study and a researcher in the psychology department at Julius-Maximilians-Universitat Wurzburg in Germany, tells Inverse.

What’s new — Researchers found that two key changes to the design of restaurant menus can provide a psychological “nudge” in the right direction, prompting customers to choose more climate-friendly options than they would otherwise.

These two measures include carbon labels indicating the number of greenhouse gas emissions associated with a particular menu item, as well as putting lower-emission meat and plant-based options as the default menu option. So instead of having a default dish with beef and allowing customers to swap it out for a lower-emission alternative, the menu might have the default option be tofu or chicken.

The researchers also designed the carbon labels to match a stoplight warning system. A green label indicates a low-emission, plant-based option like falafel, a yellow label means a medium emission meat item like chicken, and a red label signifies a high-emission option like beef.

“Our primary motivation was to establish how soft measures such as carbon labels and default switches in restaurants can contribute to the struggle against the climate crisis in the context of dining,” Seger says.

According to the paper, these two measures taken together “significantly reduce” the number of high-emission dishes that customers chose, thereby confirming the researchers’ assumption that “using climate-friendly dishes as default options fosters climate-friendly dining.” On average, the menu design resulted in a 31 percent decline in greenhouse gas emissions per dish when the lower-emission dish was positioned as the default.

How they figured it out — The researchers first conducted a pilot study with 100 participants to determine which dishes to include on a potential menu for each restaurant and designed their study based on real restaurant menus. The researchers settled on two types of restaurant menus and tested both with participants. The first was an unchanging menu featuring dishes that couldn’t be modified. The second option consisted of variable menus informing diners they could swap out the default protein in their meal for alternative higher or lower-emission options.

The final study involved 256 volunteers, largely from Germany, who viewed menus from nine hypothetical restaurants before ultimately choosing one dish from each restaurant. Some volunteers received menu items with labels indicating carbon emissions and others did not. Researchers asked questions to make sure participants understood the meaning of the carbon labels.

Since the study occurred in the summer of 2020 as the Covid-19 pandemic was underway, the researchers conducted the study online. This choice came with some drawbacks. For example, you can’t replicate online the smells and other psychological factors — like having to actually pay for a meal — that could influence a diner’s choice in a real restaurant.

“Indeed, that's one of the weaknesses of our study, and we're quite sure that the effects we found in the online study could be somewhat weaker when applied to real restaurant settings,” Seger says.

But an online study also provided new avenues for the researchers to explore, such as testing out menu options in a wide range of cuisines ranging from Italian to Indian food.

Why it worked — “There are several psychological concepts that can explain why the default changes and the carbon labels should (and actually did) change dish choices,” Seger says.

The first reason is obvious: The menu provided information about the environmental impact. But the information was also delivered using the attention-grabbing stoplight system. Most people understand the use of red color for high-emission choices, which offers a warning to consumers much like a red stoplight does for drivers.

“So the red label says: ‘You shouldn't eat that because it harms our climate,” Seger explains.

Finally, placing a more environmentally-friendly option — like tofu in coconut curry instead of beef — in the default position can establish plant-based options as a socially normal choice, thereby changing consumer attitudes toward vegetarian meals.

But there were other variables that complicated the outcome of the study. For example, men chose higher-emission foods at a significantly higher rate than women, and individuals who typically eat meat-heavy diets were less likely to switch to vegetarian or vegan meals even when the menus include default, low-emission options or carbon labels.

“However, this does not mean that the labels have no influence on their decision,” Seger says.

Participants who normally eat meat may not always choose plant-based options because of the menu design, but the labels and default options can compel them to switch from high-emission meat options — like beef — to lower ones such as chicken.

Seger adds that the effect of the menu changes on participants’ behavior was “stronger than we expected.”

Why it matters — Recent reports suggest that changing food habits are already reducing the climate impact of our food choices, but we need to more urgently reduce our greenhouse gas emissions to keep global temperatures from dangerously rising, according to a landmark report by the UN Intergovernmental Panel on Climate Change (IPCC).

A 2021 study found that the food industry contributes one-third of global greenhouse gas emissions. Meat alone is responsible for 60 percent of greenhouse gas emissions from the food industry — twice the amount of plant-based foods — due to practices like cutting down trees for grazing land and methane emissions from cow belches.

Yet most studies analyzing how consumers can eat more climate-friendly options focus on cooking in the home, not eating out. A 2020 study suggests that labeling restaurant menus with calorie amounts can guide diners toward healthier eating (though other research finds calorie labels have little impact on consumer decisions) so a similar psychological process could potentially steer us toward a greener plate for the planet.

What’s next — Seger hopes their findings will help climate-minded restaurants tailor their menus to feature climate-friendly choices.

“We want to encourage restaurant owners to switch to green defaults and introduce carbon labels,” Seger says.

If some restaurants start voluntarily adopting these measures, Seger believes others will likely follow suit, so it won’t be necessary for governments to introduce legal mandates for carbon labels.

“In our view, the most important thing is that these menu design measures become more popular and we hope this study contributes to that,” Seger concludes.