Young adults and aging populations drive food-related GHG emissions, study urges age-specific strategies

A study has found age to be an important factor in shaping food-related greenhouse gas (GHG) emissions, driven by differences in nutritional needs, demographic change, and dietary patterns. Adolescents and young adults showed the highest dietary GHG emissions per capita globally. Another contributing factor is the expanding senior population in high-income countries. 

The international study was carried out by researchers from institutions across Germany, the UK, the Netherlands, China, and Hong Kong. They compared dietary emissions and nutritional quality across 149 countries and included 22 age groups between five time periods spanning 2000 and 2019.

“Understanding who contributes to dietary emissions is essential for designing effective climate solutions. Sustainable diets, therefore, need to account for differences across life stages, nutritional requirements, and regional contexts,” says co-author of the study Yuli Shan, professor at the University of Birmingham, UK.

Carbon-heavy diets

Published in nature food, the study found that the consumption of meat and dairy products, which are major sources of dietary emissions, remains high, especially in high-income countries.

The researchers also observed a high impact from changing consumption patterns. In the two most populous countries, China and India, increased consumption of meat and dairy was reported.

In the two most populous countries, China and India, increased consumption of meat and dairy was reported.“Chinese adolescents and young adults contributed 34.3% and 35.1%, respectively, to the total per capita dietary emission increase within each age group from 2000 to 2019. By contrast, in India, per capita emission growth was dominated by dairy products, which accounted for over 90% of the total dietary emission increase and approximately half of the total dietary emissions across all age groups in 2019,” reads the study.

In the remaining Southeast Asia region and Indonesia, the dominant dietary emission source is refined grains, rice in particular. The study notes that refined grains accounted for up to 51% of dietary emissions in 2019 among young adults and adolescents in these regions.

“In many low- and middle-income countries, dietary shifts toward certain nutrient-rich foods have improved nutritional quality, but have also contributed to rising emissions. This means that simply reducing certain types of food may have unintended health effects,” highlights study co-author Klaus Hubacek, professor at the University of Groningen, the Netherlands.

To reduce food-related GHG emissions, the study suggests improving food production systems, supporting sustainable dietary transitions, and tailoring any steps for improvement to local conditions.

The researchers note that to transform the food system into a more sustainable one, there is a need for demographic shifts, nutritional needs, and dietary patterns to be addressed at a local level rather than following a universal approach.

“For younger populations, this highlights the importance of education and sustainable food environments, including approaches that encourage schoolchildren to switch to healthier meals with lower carbon emissions,” adds co-author of the study Prajal Pradhan, an associate professor at the University of Groningen.

Dietary patterns driving emissions

Looking beyond geographical dietary patterns, the study found that adolescents aged 11 to 19 and young adults aged 20 to 29 had the overall highest emissions per capita globally, with exceptions for some countries in sub-Saharan Africa and Oceania.

Young people had the overall highest emissions per capita.Across regions, the lowest emission per capita group was children aged zero to 10 due to their lower energy requirements and caloric intake compared with older age groups, the authors note.

The study details that in multiple Asian regions, including Japan, China, the rest of South Asia, and Southeast Asia, including Indonesia, increases in meat-related emissions among adolescents were generally about twice as high as those among children or seniors.

In high-income countries such as the US, Japan, and countries in Western Europe, emissions were predominantly driven by an expanding senior population, rather than dietary choices among this population.

“Older people are often seen as having a higher contribution to carbon emissions. We found a more nuanced pattern: the increasing contribution of seniors to dietary emissions is driven largely by a rising share of seniors in the population, rather than more carbon-intensive diets among seniors,” comments study co-author Yanxian Li, a prior Ph.D. student at the University of Groningen during the research and now with Chongqing University, China.

The study concludes that “dietary-emission mitigation priorities should move beyond one-size-fits-all approaches and account for differences across age groups.”