Food production is a main contributor to climate change, constituting around one-quarter of carbon emissions worldwide.
A study that analyzed the real-world diets of thousands of people in the United States reported that the carbon footprint of what people consume could be significantly decreased by varying just one food each day.
We found that making one substitution of poultry for beef resulted in an average reduction of dietary greenhouse gases by about a half.
Diego Rose, PhD, Study Lead Author, Professor, and Director of Nutrition, Tulane University
Rose will exhibit the work at Nutrition 2019, the American Society for Nutrition annual meeting, conducted from June 8th to 11th, 2019 in Baltimore.
“To our knowledge, this is the only nationally representative study of the carbon footprint of individually chosen diets in the U.S.,” stated Rose. “We hope this research will raise awareness about the role of the food sector in climate change and the sizable impact of a simple dietary change.”
The new research is conducted on the basis of the diet information obtained from over 16,000 participants in the 2005–2010 National Health and Nutrition Examination Survey. A section of this survey asked participants to recall all the foods they ate in the last 24 hours. The scientists used this information to find out which foods had the highest greenhouse gas emissions and to estimate a carbon footprint for each individual diet.
They identified that the 10 foods with the highest environmental footprint were all pieces of beef and that around 20% of participants were estimated to eat one of these high-carbon foods. Using simulation, the scientists estimated a new carbon footprint for each diet by substituting beef with the nearest associated poultry product. For instance, ground beef was replaced with ground turkey and the broiled beef steak was replaced with broiled chicken. Each replacement was done only one time for each person who ate one of the high-carbon foods.
Animal foods are proven to contribute more to greenhouse gas emissions when compared to plant foods. Ruminant animal foods like beef and lamb, in particular, have high carbon footprints since sheep and cows also liberate methane gas.
“Our simulation showed that you don’t have to give up animal products to improve your carbon footprint,” said Rose. “Just one food substitution brought close to a 50% reduction, on average, in a person’s carbon footprint.”
The scientists intend to extend this work, which addressed dietary greenhouse gas emissions, to include other environmental effects like water use.
While it is not the focus of this study, they denote that food waste and overeating also elevate the carbon footprint of the diet. Therefore, in addition to consuming low-carbon foods, better meal planning and consuming remains can also help decrease carbon footprint.