New Delhi: Adolescents and young adults generate the highest individual food-related greenhouse gas emissions globally, but older people are now the fastest-growing contributors to dietary emissions as populations age, according to a new international study.
The research, led by the University of Birmingham in the UK and published in the journal Nature Food, analysed dietary patterns across 149 countries and 22 age groups between 2000 and 2019.
The study found that while teenagers and young adults generally have the highest per capita environmental impact from food consumption, the rapid growth in older populations is increasingly driving global dietary greenhouse gas (GHG) emissions, particularly in high-income countries.
India and China show different dietary drivers
The researchers found that rising dietary emissions in India and China—the world's two most populous countries—were driven by different food choices.
In India, dairy products accounted for more than 90 per cent of the increase in per capita dietary emissions and contributed about half of total dietary emissions across all age groups in 2019.
In China, meat consumption was the dominant factor. Meat-related emissions accounted for more than 40 per cent of total per capita dietary emissions among adolescents and young adults, contributing over one-third of the increase in dietary emissions within those age groups between 2000 and 2019.
Population ageing increasing global emissions
The study estimated that global dietary emissions increased by 2.1 gigatonnes of carbon dioxide equivalent (GtCO₂e) between 2000 and 2019.
Older adults accounted for the largest share of this increase, contributing 25.4 per cent of the global rise in emissions.
Researchers said this trend is largely linked to demographic changes rather than worsening diets among older people. As populations age because of longer life expectancy and lower birth rates, the overall contribution of seniors to food-related emissions has increased.
In high-income regions, including the United States, Western Europe and Japan, older adults accounted for between 22 and 29 per cent of national diet-related emissions.
Meat remains the biggest global driver
The researchers identified increasing meat consumption, particularly red meat, as the single largest contributor to rising dietary emissions worldwide. They also found that higher meat intake often coincided with declining nutritional quality.
Lead author Yuli Shan, professor at the University of Birmingham, said the findings challenge the assumption that older people are the most carbon-intensive consumers.
He said emerging economies face a growing policy dilemma as rising incomes encourage greater consumption of animal products, increasing emissions while governments must also ensure adequate nutrition.
The researchers called on policymakers to consider age-specific dietary trends when designing climate and food policies aimed at reducing emissions while maintaining nutritional security.
