A global analysis led by researchers at the Friedman School of Nutrition Science and Policy at Tufts University, published in Nature Food, finds that many healthy diets can be both cheaper and lower in greenhouse gas emissions than commonly eaten diets. The study is intended to inform policy discussions about reducing emissions from the food system without increasing food insecurity.
The authors used the Healthy Diet Basket targets that UN agencies and national governments use for global monitoring. They identified locally available foods that meet basic nutritional needs and compiled three data types for each item: availability and price in each country, how much of the country’s food supply it represents, and the global average greenhouse gas emissions associated with that product. For each country they modeled five diets: the healthiest diet with the lowest emissions, the healthiest diet at the lowest cost, and three versions based on the most commonly consumed foods.
The numerical results include: the common-products healthy diet (reference year 2021) at 2.44 kilograms CO2-equivalent per person per day and a cost of $9.96 per day; the benchmark diet to minimize climate harms at 0.67 kilograms and $6.95 per day; the healthy diet designed to minimize monetary cost at 1.65 kilograms and $3.68 per day; and a blended scenario at 1.86 kilograms and about $6.33 per day.
In most food groups the lowest-cost options also had lower emissions because they generally use less fossil fuel and cause less land-use change. Important tradeoffs appear at the extremes: milk is often the least expensive animal-source option and emits much less than beef, while small fish such as sardines and mackerel can have even lower emissions at intermediate cost per calorie. Rice is often the cheapest starchy staple but can produce more methane than wheat or corn in some countries because flooded paddies emit microbial methane. The researchers note that some emissions reductions will require investment, but choosing cheaper items at the grocery store can often reduce a diet’s climate footprint.
Difficult words
- greenhouse gas emissions — gases released by human activity that warm climate
- food insecurity — lack of reliable access to enough food
- land-use change — change in how land is used or managed
- tradeoff — situation where gaining something loses something elsetradeoffs
- benchmark — standard used for comparison or measurementbenchmark diet
- availability — whether something can be obtained or found
- methane — a greenhouse gas from decomposing organic mattermicrobial methane
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How could governments use the study's finding to reduce food-system emissions without increasing food insecurity?
- What tradeoffs should consumers consider when choosing cheaper animal-source foods like milk versus beef?
- Name some affordable local foods in your area that might lower both diet cost and emissions. Why?
Related articles
How mangroves survive saltwater
Scientists studied mangrove trees to learn why some plants tolerate repeated saltwater flooding. They found small cells and thicker cell walls help mangroves stay strong in salty, waterlogged conditions and suggest this could help make crops more salt-tolerant.
Uzbekistan builds large waste-to-energy plants with Chinese partners
Uzbekistan began construction of two waste-to-energy plants with Chinese firms in July 2025 and plans at least seven plants by 2027. The projects aim to burn waste and produce electricity, but critics raise transparency and health concerns.
Chepang Landscape proposed as an OECM in Nepal
The Government of Nepal has proposed the Chepang Landscape as an Other Effective area-based Conservation Measure (OECM). The area is community-managed and important for biodiversity, but land-rights and cultural concerns must be addressed.
