ANN ARBOR, Mich. — Forget low-carb diets. It’s lower-carbon diets that may be the best option. A new study finds that not only are lower-carbon diets better for the environment, they’re also great for our bodies.
The study, conducted by researchers from the University of Michigan and Tulane University focused the carbon footprint of what more than 16,000 Americans eat each day. The authors say this study was the first of its kind to compare the climate impact and nutritional value of diets using real-world, real-time data.
“We hope these findings will help the public and policymakers recognize that improving diet quality can also help the environment,” says study co-author Martin Heller, a researcher at the UM Center for Sustainable Systems at the School for Environment and Sustainability, in a release.
Carbon-heavy foods like red meat and dairy are also generally less healthy than foods relying on fewer carbon emissions, like poultry, whole grains, and plant-based proteins. Previous research has shown that just eliminating beef from the American diet would allow the nation to fulfill 50 to 75 percent of its target greenhouse gas reductions by 2020,
For this study, the researchers created a database containing the greenhouse emissions from the production of different food products and cross-referenced it with a large, national survey that asked participants what they ate over a 24-hour period. Then they ranked participants’ diets by the amount of greenhouse gas emissions per 1,000 calories and split them into five groups, which were rated from highest to lowest impact when it came to carbon footprint.
The authors found that diets in the lowest-impact group also tended to be healthier, as measured using the U.S. Healthy Eating Index, a federal standard of diet quality. The highest-impact diets were, not surprisingly, found to include more animal-based proteins, particularly red meat and high-fat dairy products.
“The good news here is that there are win-win solutions with diets that are healthier for people and planet,” says Heller. “Big reductions in food-related emissions don’t require eliminating foods entirely: moderate shifts away from red meat and toward beans, eggs or chicken can lead to significant improvements in both health and our diet’s carbon footprint.”
Heller warns, however, that some of these lower-impact diets did contain items that had more added sugars or refined grains, which should be avoided. The lack of meat and dairy also meant lower intake of iron, calcium, and vitamin D.
The study was published in the American Journal of Clinical Nutrition.