Changes in diet have been discussed as a way to reduce carbon emissions within the food system, but there has been little research to date on the affordability and feasibility of low-carbon food choices in the U.S. Until now.

A new study by the University of Connecticut offers the most comprehensive estimate of greenhouse gas emissions generated by U.S. consumer food purchases. The findings suggest that if Americans directed their food purchases away from meats and other animal proteins, they could help reduce greenhouse gas emissions.

Food purchases accounted for 16 percent of U.S. greenhouse gas emissions in 2013, according to the study, published June 7 in the journal Food Policy. By comparison, commercial/residential activity accounted for 12 percent, and industrial activity accounted for 21 percent of the nation’s greenhouse gas emissions.

The study was led by researchers at the UConn Rudd Center for Food Policy and Obesity; UConn Zwick Center for Food and Resource Policy; Tufts University Friedman School of Nutrition Science and Policy; the University of Missouri; and the U.S. Department of Agriculture’s Economic Research Service.

“We found that households that spend more of their weekly food budget on beef, chicken, pork, and other meats are generating more greenhouse gas emissions,” says Rebecca Boehm, the study’s lead author and a postdoctoral fellow at UConn. “Encouraging consumers to make food choices that are lower in greenhouse gas emissions can make a real difference addressing climate change.”

Key findings include:

• Industries that produce beef, pork, and other red meat generated the largest share of greenhouse gas emissions from household purchases, approximately 21 percent, followed by fresh vegetables and melons (11 percent), cheese industries (10 percent), and milk products and butter (7 percent).
• Greenhouse gas emissions generated by household food spending varied by race and educational attainment. More than 80 percent of households generating very high greenhouse gas emissions from their food spending (top fifth of households) were white. Twenty-six percent of households in the highest (top fifth) tier of greenhouse gas emissions had a survey respondent with a college degree, compared to approximately 12 percent in the bottom fifth for greenhouse gas emissions.
• Participation in the federal Supplemental Nutrition Assistance Program (SNAP) was associated with less greenhouse gas emissions from food spending (when not accounting for other household characteristics). Approximately 24 percent of households in the bottom fifth for greenhouse gas emissions participated in SNAP; only 9 percent of households in the top fifth for greenhouse gas emissions participated in SNAP.

“For the first time, our study shows the association between the greenhouse gas emissions generated by the food system, household food spending patterns, and sociodemographic characteristics,” Boehm says. “These findings can inform the debate on which diets and food spending patterns can best mitigate greenhouse gas emissions from the food system, while informing educational efforts to encourage low-carbon diets among the U.S. population.

“This study is a major advancement in understanding the contribution of U.S. food choices to climate change,” according to Boehm.

Study co-authors include Parke Wilde and Sean B. Cash of the Friedman School of Nutrition Science and Policy at Tufts University, Shelly Ver Ploeg of the USDA Economic Research Service, and Christine Costello of the University of Missouri.

The study was supported by the Zwick Center, the Friedman Family Foundation Doctoral Fellowship, and the Tufts Institute of the Environment.