A study by the Johns Hopkins University Bloomberg School of Public Health has found that including climate impact labels on a sample fast food menu influenced participants’ food choices in favour of more climate-friendly items.

For the study, lead author Julia Wolfson, PhD, associate professor in the Department of International Health at the Bloomberg School and her co-authors said that they wanted to test how signalling climate change impacts of fast-food menu items might prompt people to opt for less red meat.

Red meat is something that the BBC has said produces the most greenhouse gas emissions, including methane. Additionally, eating red meat has been linked to health problems such as colorectal cancer, stroke, type 2 diabetes, and other illnesses.

For the investigation over 5,000 online participants were shown a sample menu resembling a fast food menu and asked to choose a single item for dinner.

One group of participants received a menu with non-red meat menu items such as chicken sandwiches labelled “low climate impact.” Another group received a menu with red meat items (burgers) labelled “high climate impact.” A third control group received menus with QR codes on all items and no climate labels.

Both the high and low climate impact labels markedly reduced red meat selections compared to the control group, with the high impact labels having a strong effect. Menus with a “high climate impact” label on burgers increased non-beef choices by 23 percent compared to the control group.

Menus that included “low climate impact” labels increased non-beef choices, such as a chicken sandwich or a salad, by about 10 percent more participants than those in the control group.

Commenting on the results of the study, lead study author Julia Wolfson, PhD, associate professor in the Department of International Health at the Bloomberg School, said: “These results suggest that menu labelling, particularly labels warning that an item has high climate impact, can be an effective strategy for encouraging more sustainable food choices in a fast-food setting.”

In addition to being asked to choose an item for dinner, participants were asked to rate how healthy they thought the item they ordered was. No matter which type of label was on the menu viewed, participants who selected a more sustainable item perceived their choice to be healthier compared to those who selected a beef item.

Utilising the Nutritional Profiling Index to measure the healthfulness of foods on a 100-point scale, (with 64 and lower considered healthful) the researchers found that the choices of the “high climate impact” label group scored slightly better than those of the control group and the “low climate impact” group. However, none of the items on the menu scored high enough to be considered optimally healthful.

Overall, the results suggest that positively framed “low climate impact” labels are less effective in encouraging sustainable food choices compared to “high climate impact” labels. At the same time, the authors noted that climate labels may have the unwanted side effect of making a choice seem healthier than it is.

“An undeserved health halo conferred to unhealthy menu items could encourage their overconsumption,” explained Wolfson.

“We have to look for labelling strategies that create ‘win-wins’ for promoting both more sustainable and healthy choices.”