Eating a healthy diet can reduce food costs and lower greenhouse gas emissions compared with what most people currently eat, according to a new global study examining the links between food prices, nutrition, and climate impact. The research shows that environmentally responsible eating does not necessarily require higher spending or specialised products, challenging a common assumption about sustainable diets.

The study was led by researchers at Tufts University’s Friedman School of Nutrition Science and Policy. They aimed to identify which locally available foods could meet basic nutritional requirements at the lowest possible cost and with the smallest climate footprint. These optimised diets were then compared with what people typically consume in different countries. The findings, recently published in Nature Food, suggest that every day, lower-cost food choices often align more closely with both health and climate goals than expected.

Using global dietary benchmarks known as Healthy Diet Basket targets—widely employed by United Nations agencies and national governments—the researchers modelled diets that satisfied nutritional needs while minimising either greenhouse gas emissions or monetary cost. They then contrasted these idealised diets with those based on the most commonly consumed foods. Across most food groups, less expensive items tended to generate fewer emissions, mainly because they require less energy, fertiliser, and land-use change during production.

The analysis drew on three primary sources of data for each food item: its price and availability in individual countries, its share of national food supplies, and its average greenhouse gas emissions. For each country, five dietary patterns were modelled, including the healthiest possible diet with the lowest emissions, the most nutritious diet at the lowest cost, and three diets reflecting typical consumption patterns.

In 2021, a healthy diet based on the most commonly eaten foods produced an average of 2.44 kilograms of CO₂-equivalent emissions per person per day and cost about $9.96 globally. By contrast, a diet designed specifically to minimise climate impact produced just 0.67 kilograms of emissions for $6.95. A diet focused solely on minimising cost, even less—$3.68 per day—while producing 1.65 kilograms of emissions. A blended approach, combining commonly eaten foods with lower-cost healthy alternatives, sat between these extremes, remaining significantly cheaper and less polluting than typical diets.

The researchers found that, in general, choosing cheaper options within each food group is an effective way to reduce dietary emissions. However, there are essential exceptions at the very lowest-cost and lowest-emission extremes. Among animal-source foods, milk is often the cheapest option and produces far fewer emissions than beef and other meats. Still, certain fish, such as sardines and mackerel, can offer even lower emissions at slightly higher cost. Among starchy staples, rice is frequently the least expensive option but has higher emissions than wheat or maize because methane is released from flooded rice paddies.

Overall, the study highlights a potential win–win for consumers and policymakers alike: healthier, more affordable, and more climate-friendly diets. While cutting emissions in other sectors often requires costly investments, everyday food choices can deliver environmental benefits simply by prioritising value for money—so long as key trade-offs are understood.

More information: Yan Bai et al, Environmental impacts and monetary costs of healthy diets worldwide, Nature Food. DOI: 10.1038/s43016-025-01270-4

Journal information: Nature Food Provided by Tufts University