For the study, over 5,000 online participants were shown a mock fast food menu and asked to select a single item for dinner. One group of participants received a menu with non-red meat menu items labelled 'low climate impact,' such as chicken sandwiches. Another group received a menu with red meat items- 'burgers'- labelled 'high climate impact'. A third control group was given menus that had QR codes on every item but no climate labels.
When compared to the control group, both the high and low-climate-impact labels significantly reduced red meat selections, with the high-impact labels having the strongest effect. In comparison to the control group, menus with a 'high-climate impact' label on burgers increased non-meat choices by 23%.
Menus with 'low-climate impact' labels increased non-meat options like a chicken sandwich or a salad by about 10% more participants than the control group. The study was published online in JAMA Network Open on December 27.
"These findings suggest that menu labelling, particularly labels warning that an item has a high climate impact, can be an effective strategy for encouraging more sustainable food choices in a fast food setting," said study lead author Julia Wolfson, PhD, an associate professor in the Bloomberg School's Department of International Health. Using menu labels to promote healthy and sustainable food options has long been considered a viable strategy.
Wolfson and her co-authors wanted to see if signalling the climate change impacts of fast food menu items would cause people to eat less red meat. Consumption of red meat has been linked to health issues such as colorectal cancer, stroke, type 2 diabetes, and other illnesses. Because meat production is the largest contributor of greenhouse gas emissions in the food and agriculture sector, reducing red meat consumption would also help to reduce greenhouse gas emissions, which would help to reduce climate change.
The study included 5,049 participants from across the country and ran from March 30 to April 13, 2022. Green "low climate impact" labels appeared on vegetarian, chicken, and fish menu items. All beef burger options had "high climate impact" labels that were red. The authors created the high/low impact climate categories based on evidence that meat has a higher climate impact than other proteins. In addition to selecting a dinner item, participants were asked to rate how healthy they thought the item they ordered was.
Participants who chose a more sustainable (i.e., non-meat) item perceived their choice to be healthier than those who chose a meat item, regardless of the type of label on the menu viewed. The Nutritional Profiling Index was used by the researchers to assess the healthfulness of the sample menu items. The Index rates the healthfulness of foods on a scale of 100, with 64 being considered healthy. The researchers discovered that the 'high-climate impact' label group performed slightly better than the control group and the 'low-climate impact' group. However, none of the menu items received a high enough score to be considered optimally healthy.
While the findings are encouraging overall, they suggest that positively framed 'low climate impact' labels are less effective in encouraging sustainable food choices than 'high climate impact' labels. At the same time, climate labels may have the unintended consequence of making a choice appear healthier than it is. "An undeserved health halo conferred on unhealthy menu items may encourage their overconsumption," Wolfson added, "so we must look for labelling strategies that create 'win-wins' for promoting both more sustainable and healthy choices."
