Food production is an important contributor to climate change, accounting for about a quarter of carbon emissions globally. If Americans changed their diets by swapping out one item each day, they could reduce their carbon footprint from food, according to a Tulane study that examined the diets of thousands of people in the United States.
“We found that making one substitution of poultry for beef resulted in an average reduction of dietary greenhouse gases by about a half,” said lead study author Diego Rose, professor and director of nutrition at the Tulane School of Public Health and Tropical Medicine.
Rose presented the research at Nutrition 2019, the American Society for Nutrition annual meeting, held in Baltimore in June.
The study is based on diet information from more than 16,000 participants in the 2005–10 National Health and Nutrition Examination Survey. A portion of this survey asked participants to recall all the foods they consumed in the previous 24 hours. The researchers used this information to determine which foods had the highest greenhouse gas emissions and to calculate a carbon footprint for each individual diet.
They found that the 10 foods with the highest impacts on the environment were all cuts of beef and that about 20% of participants reported consuming one of these high-carbon foods. Using simulation, the researchers calculated a new carbon footprint for each diet by replacing beef with the closest related poultry product. For example, a broiled beef steak was replaced with broiled chicken and ground beef with ground turkey.
Animal foods are known to contribute more to greenhouse gas emissions than plant foods. Ruminant animal foods such as beef and lamb have particularly high carbon footprints because cows and sheep also release methane gas.“
Our simulation showed that you don’t have to give up animal products to improve your carbon footprint,” Rose said. “Just one food substitution brought close to a 50% reduction, on average, in a person’s carbon footprint.”