Lower-carbon diets are good for people, planet

Diets with less red meat, dairy help lower carbon footprint

A new Tulane University study concludes that diets that are more climate-friendly are good for the planet and people too.

“People whose diets had a lower carbon footprint were eating less red meat and dairy, which contribute to a larger share of greenhouse gas emissions and are high in saturated fat, and consuming more healthful foods like poultry, whole grains and plant-based proteins,” according to Diego Rose, lead author and a professor at Tulane University School of Public Health and Tropical Medicine.

The study was published in the American Journal of Clinical Nutrition, and also by EurekAlert, an online publication of the American Association for the Advancement of Science.

Researchers from Tulane and the University of Michigan tracked the impact of Americans’ daily food choices and their connection to climate change with a database of greenhouse gas emissions related to food production and linked it to a large federal survey that asked people what they ate over a 24-hour period.

Diets were ranked by the amount of greenhouse gas emissions per 1,000 calories consumed and divided into five equal groups. Then researchers rated the nutritional value of foods consumed in each diet using the U.S. Health Eating Index, a federal measure of diet quality, and compared the lowest to the highest-impact groups on this and other measures.

Americans in the lowest carbon footprint group ate a healthier diet, as measured by this index. However, these diets also had more of some low-emission foods that aren’t healthy, namely added sugars and refined grains, and lower amounts of important nutrients, like iron calcium and vitamin D, likely because of lower intake of meat and dairy.

Diets in the highest impact group accounted for five times the emissions of those in the lowest impact group. They had higher amounts of meat, dairy and solid fats per 1,000 calories than the low-impact diets. Overall, the high-impact diets were more concentrated in total proteins and animal protein foods. A companion study released earlier this year found that 20 percent of Americans accounted for almost half of the U.S. diet-related greenhouse gas emissions.

Rose said he hoped the research will held the public and policymakers recognize that improving diet quality can also help the environment.

“For example, if we reduce the amount of red meat in our diets and replace it with other protein foods such as chicken, eggs or beans, we could reduce our carbon footprint and improve our health at the same time,” he said.