Food choices play a crucial role in both human health and environmental sustainability. High consumption of animal-based products not only contributes to greenhouse gas (GHG) emissions but is also linked to obesity and various non-communicable diseases. Despite advancements in food production efficiency, GHG emissions continue to rise, intensifying climate change. Concurrently, over 800 million people face hunger, with many unable to access a nutritious diet.
Previous studies have indicated that adopting healthier diets, such as the planetary health diet proposed by the EAT-Lancet Commission, could reduce GHG emissions and improve health outcomes. However, further research is needed to understand the impact of these dietary changes on different demographic groups.
About the Study
A recent study analyzed GHG emissions from diets in 139 countries for the year 2019. Researchers used data on 140 food products to estimate emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (NOx) from the entire food supply chain, from production to consumption. The study assessed emissions based on household expenditure information, with the potential effects of adopting the planetary health diet modeled for each country.
Data sources included global food production and trade monitors, as well as household expenditure surveys. Findings were adjusted to account for food waste at the household level to better reflect actual dietary intake and its impact on GHG emissions.
Study Findings
In 2019, global dietary emissions totaled 11.4 gigatons of CO2, with China and India being the largest contributors. Emission levels varied widely by country, with Bolivia having the highest per capita emissions and Haiti and Yemen the lowest. Animal-based products, especially red meat and dairy, were significant contributors to emissions despite providing fewer calories compared to plant-based foods.
Regionally, emissions from animal-based products were highest in Australia, the United States, and East Asia, while plant-based emissions were more prominent in Southeast Asia and sub-Saharan Africa. Wealthier populations generally had higher emissions due to greater consumption of animal-based foods, while poorer populations relied more on staple foods like grains and tubers, leading to lower emissions.
The study projected that adopting the planetary health diet could reduce global emissions by 17%, with the most significant reductions from decreased red meat consumption. However, emissions might rise in low-income countries as their diets become more diverse.
Conclusions
The study underscores the uneven distribution of dietary emissions and the potential for sustainable diets to reduce global emissions. Transitioning to the EAT-Lancet planetary health diet could cut emissions by 17%, but effective implementation would require region-specific policies. Low-income countries face barriers to adopting healthier diets due to high costs and limited availability of nutritious foods. Addressing these challenges will involve improving agricultural efficiency, increasing the availability of affordable nutrient-rich foods, and supporting vulnerable populations.
Significant changes in food production and consumption would also impact agricultural markets, necessitating careful policy planning to mitigate potential negative effects on food prices and producers.
Study Limitations and Future Research
The study has notable limitations, including reliance on regional data for food waste and consumption patterns, which may not accurately represent national variations. Additionally, the assumption of consistent food prices and consumption patterns across income groups may not reflect actual conditions. Key populous countries were also excluded from the data, potentially affecting global estimates.
Future research should explore the effects of shifts in food supply sources, such as changes in domestic production and imports, on GHG emissions. Further studies should also assess the economic impacts of dietary changes on household incomes, particularly in regions reliant on food production. Incorporating price elasticity models could provide insights into the long-term feasibility and economic consequences of adopting more sustainable diets.