Researchers explored how different dietary changes could reduce the carbon footprint of food consumption.
A single change at the dinner table could have a bigger climate impact than many people realize.
Researchers in the UK found that replacing just one beef steak per week with salmon could significantly reduce food-related carbon emissions over time. In fact, the projected savings are comparable to the emissions associated with a round-trip flight from London Heathrow to Marrakech, Morocco. The finding comes from a broader study that examined how different eating patterns could shape the UK’s environmental footprint through 2050.
The study, published in Environmental Research: Food Systems, arrives as governments and scientists increasingly focus on food systems as a major source of greenhouse gas emissions. While transportation often dominates climate discussions, food production accounts for a substantial share of global emissions, with livestock production among the largest contributors.
Researchers from the University of Bristol and the University of Southampton analyzed data from 4,000 households in the UK’s Family Food Dataset to estimate how various dietary shifts could affect future emissions. Their analysis compared five scenarios:
- Business as Usual (BAU): Continuing current dietary trends
- REDUCE: Eating less meat and dairy overall
- SWAP: Replacing one beef steak with salmon each week
- NHS Eatwell: Following official NHS dietary recommendations
- Planetary: Adopting the EAT-Lancet Planetary Health Diet
Modeling the Climate Impact of Dietary Changes
If eating habits continue to change at the same pace seen between 2001 and 2021, the researchers estimate that food-related emissions would decline by 15% by 2050 under the BAU scenario. That reduction is roughly equivalent to the carbon footprint of a round-trip flight between London Heathrow and Madrid, Spain (2,486 km (1,545 miles)).
The simple salmon swap produced a much larger effect. Replacing one serving of beef steak per week with UK-produced salmon was projected to reduce emissions by 28% by 2050. The savings are comparable to the emissions from a round-trip flight between London Heathrow and Marrakech, Morocco (4,583 km (2,848 miles)).
The REDUCE scenario cut emissions by 39%, equivalent to a round-trip flight to Cyprus (6,565 km (4,080 miles)). Following the NHS Eatwell diet lowered emissions by 42%, comparable to a round-trip flight to Tel Aviv, Israel (7,186 km (4,465 miles)). The Planetary diet delivered the largest reduction at 49%, roughly equal to the emissions from a round-trip flight between Heathrow and Baku, Azerbaijan (8,024 km (4,986 miles)).
The researchers say that adopting dietary changes such as these could help countries meet carbon reduction goals.
Lead author Dr. Jenny Baverstock, Honorary Research Fellow in Bristol’s School of Biological Sciences and former Principal Enterprise Fellow at the University of Southampton, said: “Taking forward simple changes in our diets and also following existing recommendations from the NHS Eatwell guide could see important reductions in carbon emissions that are necessary for environmental sustainability. Our simple swap offers a nutritional/health advantage as well as an environmental one which is ideal as these two need to go hand in hand and not be traded off against each other.”
Food Systems and Emissions
Worldwide, food and agriculture account for 26% of human-caused emissions. In the UK, the sector contributes about 20%. Researchers note that emissions have already been declining and could fall further through dietary changes, helping support the UK government’s goal of reaching net-zero emissions by 2050.
Animal agriculture generates 82.5% of emissions linked to the global food sector. Red meats such as beef, lamb, and pork are among the largest contributors. Lower-impact protein sources, including fish, chicken, and legumes, offer alternatives that produce fewer emissions.
The researchers selected beef and salmon because the swap is relatively simple and realistic for many consumers. Both foods are also commonly produced in the UK.
By 2050, the model projected that this single dietary change would reduce emissions by 7.30 kg of CO2 per person each week (16.1 pounds), highlighting the potential impact of small adjustments in food choices.
The researchers acknowledge that changing eating habits across an entire population is difficult and would involve tradeoffs. Any transition would likely require support for livestock farmers as well as measures to ensure sustainable growth in the fishing industry.
At the same time, seafood consumption in the UK is currently 31% below government recommendations. Researchers also point to strong evidence linking processed meat and unprocessed red meat consumption to a higher risk of developing type 2 diabetes.
Professor Guy Poppy, Pro Vice-Chancellor for Research and Innovation at the University of Bristol and a co-author of the study, said: “Given the public concern about planetary health this substitution of salmon for beef may gain traction with the public if, as well as promoting individual health there is more awareness around eating more sustainably. This offers an easy choice for people whom want to reduce their environmental footprint.
“In 2026, we face unprecedented trade challenges with the turbulence of the trade tariffs levied by the US and counter responses globally which raise questions around national food security and the role of a global food system. This might create additional opportunities for the UK to examine the domestic supply of fish for future stability, in particular, protein security.”
Reference: “Adapting the source of protein in diets to reduce carbon emissions: a UK case study exploring aquaculture” by Jenny Baverstock, Daniel Romero-Saavedra and Guy Matthew Poppy, 26 May 2026, Environmental Research: Food Systems.
DOI: 10.1088/2976-601X/ae6709
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