Low carbon diets are not only good for the planet, they are also healthier

A new study examining the carbon footprint of what more than 16,000 Americans consume each day is good news for environmentally conscious consumers: more climate-friendly diets are also healthier.

The study, conducted by researchers at the University of Michigan and Tulane University, is the first to compare the impact on climate and nutritional value of American diets using real data on what Americans say eat.

Online publication is planned for the newspaper. American Journal of Clinical Nutrition January 24th.

"We hope these results will help the public and policy makers recognize that improving the quality of food can also help the environment," said Martin Heller, co-author of the 39, study of the UM Center for Sustainable Systems at the School for Environment and Sustainability.

"People whose diets reduced the carbon footprint were consuming less red meat and dairy products – which contribute to a greater share of greenhouse gas emissions and are high in saturated fat – and consumed more calories. healthier foods like poultry, whole grain cereals and vegetable protein, "said lead author Diego Rose, professor of nutrition and food safety at Tulane University School of Public Health and Tropical Medicine.

Since food production is a major contributor to climate change, researchers have sought to find out more about the consequences of Americans' daily food choices. They built an extensive database of greenhouse gas emissions related to food production and linked it to an extensive federal survey asking people what they ate on a diet. 24 hours period.

The researchers ranked diets by the amount of greenhouse gas emissions per 1,000 calories consumed and divided them into five equal groups. Next, they badessed the nutritional value of the foods consumed in each diet using the US Healthy Eating Index, a federal measure of food quality, and compared the groups with the lowest impacts to the most important ones. .

Americans in the lower carbon group ate a healthier diet, as measured by this index. However, these diets also contained a greater number of unhealthy products, namely added sugars and refined cereals. They also had a smaller amount of important nutrients – such as iron, calcium and vitamin D – probably because of lower intakes of meat and dairy products.

Overall, lower-impact group diets were healthier, but not for all measures. Rose says that's because diets are complex with many ingredients that each influence nutritional quality and environmental impacts.

"This explains the nuanced relationship we observed between these results," he said.

The group's diets with the greatest impact represented five times the emissions of those in the group with the lowest impact. High-impact diets had higher amounts of meat (beef, veal, pork and game), dairy products and solid fat per 1,000 calories than low-impact diets.

Overall, high – impact diets were more concentrated in total protein and animal protein foods. A related study released last year by the researchers found that 20% of Americans were responsible for nearly half of the US-related greenhouse gas emissions.

"The good news is that there are win-win solutions with healthier diets for men and the planet," Heller said. "Significant reductions in food-related emissions do not require a complete elimination of food: moving from red meat to beans, eggs or chicken can lead to significant improvements in both health and safety. and on the carbon footprint of our diet. "

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University of Michigan