Led by researchers from the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University, the study identified the locally available food items that would meet basic nutritional needs with the absolute lowest possible level of greenhouse gas emission and the lowest monetary cost, and compared those diets with foods actually consumed.

The findings, which appear in the journal Nature Food, challenge the widespread assumption that climate-friendly healthy eating requires paying more for premium products.

“People can’t see or taste the emissions caused by each food, but everyone can see the item’s price—and within each food group, less expensive options generally cause less emissions,” says Wiliam A. Masters, senior author and a professor at the Friedman School.

As governments and international organizations explore how to cut food system emissions without worsening food insecurity, the findings address a potential win-win: healthy diets that are both cheaper and more climate friendly.

For the study, Masters and his co-investigators sought to identify which foods would be the most sustainable way to meet nutritional requirements, based on the Healthy Diet Basket targets used for global monitoring by UN agencies and national governments around the world.

The team analyzed three kinds of data about each food item: its availability and price in each country, how much of each country’s food supply it accounted for, and the global average greenhouse gas emissions associated with that product.