Replacing beef on your plate with chicken will cut your dietary carbon footprint by half, according to a first-ever national study of U.S. eating habits and their carbon footprints.

To find out what Americans are actually eating, the National Health and Nutrition Examination Survey asked more than 16,000 participants to recall all the foods they had consumed in the previous 24 hours.

Researchers then calculated the carbon emissions of what people said they ate. If a meal involved beef, such as broiled beef steak, researchers estimated what the carbon footprint would be had they chosen to eat broiled chicken instead.

“We knew eating chicken instead of beef would lower carbon emissions related to diet but it was much lower than expected,” says Diego Rose, a researcher at Tulane University’s School of Public Health and Tropical Medicine and lead author of the study.