A major review in Frontiers in Science highlights how tackling unsustainable food systems—reflected by our changing food environment—is urgent for both health and climate.

The paper reviews evidence that both obesity and environmental harms result from a profit-led food system that encourages high intake and poor health. The authors say that our food environment promotes high-calorie, low-fiber products such as some ultra-processed foods (UPFs)—the most calorific of which encourage weight gain. Those same production systems, especially involving animals, release large amounts of greenhouse gases and put pressure on land and water.

The comprehensive review, led by Prof Jeff Holly at University of Bristol, UK, says that addressing the food environment can therefore deliver double benefits for health and climate. The authors recommend using subsidies for healthy foods, taxes and warning labels for particularly unhealthy foods, and restrictions on aggressive marketing of high-calorie, low-fiber products, particularly in low-income communities and to children.

They also counter the perception that weight-loss drugs are a panacea for obesity, as they do not address the systemic drivers which also harm the climate. “While obesity is a complex disease driven by many interacting factors, the primary driver is the consumption-driven transformation of the food system over the last 40 years,” said Prof Holly. “Unlike weight loss drugs or surgery, addressing this driver will help humans and the planet alike.”

By 2035, half the world’s population is projected to be living with overweight or obesity—diseases which increase the risk of serious conditions such as heart disease and cancer. Meanwhile, global heating now kills one person every minute around the world, accounting for around 546,000 deaths per year over the period 2012-2021, up 63% from the 1990s.

Food production is responsible for between a quarter and a third of total greenhouse gas emissions, and is the leading cause of land clearance, which drives deforestation and biodiversity loss. The authors note that even if fossil fuel emissions ended today, current food systems alone could still push global temperatures beyond the 2°C threshold. Ruminant meat production is particularly impactful, with beef generating far greater emissions than plant-based sources.

“We can’t solve the climate crisis without transforming what we eat and how we produce it,” said first author Prof Paul Behrens from University of Oxford, UK and Leiden University, the Netherlands. “To tackle the climate crisis, we must tackle food systems that push up emissions and push us toward energy-dense and highly processed diets full of animal products.”