Embargoed copy of the research paper available on request
Teenagers and young adults tend to have the highest individual environmental impact from their diets, but population ageing is contributing to increases in global dietary greenhouse gas (GHG) emissions - not because older people eat worse diets, but because of increasingly ageing populations.
Publishing their findings today (16 July) in Nature Food , an international research team led by the University of Birmingham, calls on policymakers to consider the urgent implications for food systems and sustainability.
The study highlights that rising emissions are often linked to poorer diet quality, creating a dual crisis of climate pressure and worsening nutrition outcomes. There is also a global inequality dimension, as in Low- and Middle-income Countries (LMIC), higher-emission diets often coincide with improving nutrition.
After analysing diets across 149 countries and 22 age groups – using data from 2000–2019 - researchers found that adolescents (11–19) and young adults (20–29) produce the highest per‑capita food-related GHG emissions worldwide.
The study reveals an important second trend: seniors (60+) are now the fastest-growing contributors to total dietary emissions, particularly in high-income countries, due to population ageing.
Researchers' key findings included:
Corresponding author Professor Yuli Shan, from the University of Birmingham, said: “Our findings challenge the dominant narrative that older populations are the most carbon-intensive consumers and prompts policymakers to face some tough challenges.
“In emerging economies, rising incomes are driving increased consumption of animal products, sharply increasing emissions among younger populations. This creates a growing dilemma for policymakers, namely, how to reduce emissions without undermining nutrition.
Leading author Yanxian Li, from Chongqing University, said: “We must rethink climate responsibility or face a policy blind spot if interventions focus on only one age group - identifying clear intervention points by age group, whether children and adolescents, young adults, or seniors.”
The study challenges ‘one-size-fits-all' climate solutions focused on diet alone, calling instead for targeted strategies tailored to age groups and development stages:
Another corresponding author Professor Klaus Hubacek, from the University of Groningen, said: “In many low- and middle-income countries, increases in emissions have occurred alongside improvements in nutritional quality, meaning that simply reducing certain types of food may have unintended health effects”.
“Food systems already account for around a third of global greenhouse gas emissions. Our research shows that - with the global population both growing and ageing - who we are, as much as what we eat, is becoming a defining factor in future climate trajectories,” said Prajal Pradhan, an associate professor at the University of Groningen and a co-author.
The rise in food-related emissions linked to older people is mostly due to there being more of them, not because their diets are especially harmful. Most of the rise in emissions among older people is simply because people are living longer and having fewer children.
In high‑income regions, older adults now account for the largest share of diet‑related emissions, reaching 22–29% of national totals across countries such as the U.S., Western Europe, and Japan. The increase is driven by population ageing rather than more carbon‑intensive diets.
Teenagers and young adults tend to eat more foods that have a high environmental impact, such as meat, dairy, sugary foods, and drinks. In developing countries, as incomes rise, young people are eating more food overall, which increases emissions further.
ENDS
For more information, please contact Tony Moran, International Communications Manager t.moran@bham.ac.uk or +44 (0)7827 832312
‘Youth lead current dietary emissions while seniors increasingly drive total emission growth’ - Yanxian Li, Jin Yan, Pan He, Prajal Pradhan, Shuai Fang, Yuli Shan , Franco Ruzzenenti, and Klaus Hubacek is published in Nature Food .
Notes for editors
Nature Food
Data/statistical analysis
People
Youth lead current dietary emissions while seniors increasingly drive total emission growth
22-Jul-2026