Generated Summary
This global modeling analysis combined analyses of nutrient levels, diet-related and weight-related chronic disease mortality, and environmental impacts for more than 150 countries. The study examined three sets of diet scenarios. The first set focused on environmental objectives, replacing animal-source foods with plant-based foods. The second set addressed food security objectives, reducing levels of underweight, overweight, and obesity. The third set, based on public health objectives, consisted of four energy-balanced dietary patterns: flexitarian, pescatarian, vegetarian, and vegan. The methodology involved calculating nutrient intake, estimating changes in mortality using a comparative risk assessment, and analyzing environmental impacts. The environmental analysis considered greenhouse gas emissions, cropland use, freshwater use, nitrogen application, and phosphorus application. The study’s objective was to analyze the relationship between the health and environmental impacts of dietary changes across different regions and dietary strategies. The focus was on how different sustainable diet approaches impact health and environmental factors, particularly in relation to chronic disease mortality and environmental footprints.
Key Findings & Statistics
- Replacing animal-source foods with plant-based ones was particularly effective in high-income countries, lowering premature mortality by up to 12% (95% CI 10–13) with complete replacement.
- Reducing underweight and overweight led to similar reductions in premature mortality (up to 10% [95% CI 9–11]).
- Following public health objectives, adopting energy-balanced, low-meat dietary patterns led to a 19% (95% CI 18–20) reduction for the flexitarian diet and a 22% (18–24) reduction for the vegan diet.
- Greenhouse gas emissions were reduced by 54–87%, nitrogen application by 23–25%, phosphorus application by 18–21%, cropland use by 8–11%, and freshwater use by 2–11% with balanced dietary patterns.
- Reductions in premature mortality due to diet patterns in 2030 showed that reductions in obesity contributed the most (61-65% across the scenarios) to the overall reduction in premature mortality.
- Reductions in underweight contributed 42-43%.
- Reductions in red meat consumption 8-11%
- Reductions in fish intake led to a 0.3-1% increase in premature mortality across the scenarios.
- Across disease endpoints, the averted premature deaths were about a quarter each from coronary heart disease (25–29%) and non-cardiovascular causes (25–30%), a fifth (19–21%) from cancer, followed by stroke (14–18%) and type 2 diabetes (8–10%).
- For the scenarios reducing animal-source foods (ani scenarios), reductions in premature mortality were positively associated with reductions in greenhouse gas emissions.
- In the ani-100 scenario, the reduction in premature mortality was 12% in high-income countries.
- In the flexitarian scenario, the reduction in premature mortality was 19% (95% CI 18-20).
- In the vegan scenario, the reduction in premature mortality was 22% (18-24).
Other Important Findings
- The study found that approaches for sustainable diets are context-specific.
- Replacing animal-source foods with plant-based diets led to improvements in nutrient levels and reductions in premature mortality, particularly in high-income countries.
- Adopting energy-balanced, low-meat dietary patterns improved nutrient supply and led to significant reductions in premature mortality.
- The environmental impacts of dietary changes varied across regions.
- In low-income countries, adoption of healthier diets can increase demand for environmental resources due to inefficient production systems.
- The study highlighted the importance of improving energy balance and changing dietary composition for achieving sustainable diets.
- In high-income and middle-income countries, replacing animal-source foods led to reduced cropland use, nitrogen, and phosphorus application.
- In low-income countries, increases in demand for legumes and vegetables can increase resource use.
Limitations Noted in the Document
- The study acknowledges that it was not able to include all aspects of sustainable diets, such as biodiversity and economic aspects.
- The analysis abstracts from real-world complexities, such as time lags between diet adoption and mortality changes.
- The study notes that residual confounding with other parameters cannot be ruled out.
- The study focuses on those risk factors that could be included on the basis of food-availability data, and does not include risk factors that would have required different methods.
- The environmental assessment is based on current environmental impacts, and the scenario changes are in line with other assessments with similar detail.
Conclusion
The study concludes that sustainable diets combine health and environmental benefits. It emphasizes that public health approaches focused on dietary changes towards plant-based diets, in line with evidence on healthy eating, perform better in reducing environmental pressures and improving health outcomes. The research highlights the regional differences in the health and environmental impacts of dietary changes. Environmental strategies like substituting animal-source foods are particularly effective in high-income countries in improving nutrient levels and lowering premature mortality, but have limited effectiveness in low-income countries. The study emphasizes the importance of addressing dietary composition and energy intake as part of food-based dietary guidelines. The study suggests that updating national dietary guidelines to reflect the latest evidence on healthy eating can be important for improving health and environmental sustainability. This study provides a comprehensive framework for analyzing the impacts of sustainable diets across different regions and emphasizes the need for context-specific strategies that balance environmental and health impacts. The results underscore the need for cross-cutting regulatory approaches that focus on the whole food environment, and include multiple incentives, including fiscal ones and support, and positive reinforcement for individuals, to promote dietary changes at the population level. The final takeaway of the research is that the combination of dietary composition and energy intake is a valuable strategy for achieving sustainable diets.
IFFS Team Summary
- Models at sustainable diets globally, in the context 150 low, middle and high income countries, and the relative ecological impact
- Uses a standard nutritional profile for incremental levels of meat reduction, health prevention, as well as semi veg, veg, and vegan diets
- i.e. each diet must attain certain level of calories, protein, and micronutrients
- i.e. each diet must attain certain level of calories, protein, and micronutrients
- Diets that were the most plant based, especially vegan achieved the most ecological benefits AND greatest health benefits
- “ Flexitarians ” reduce premature mortality by 19%, and vegans by 21% (the document actually mentions vegans)
- See FULL ENTRY in the Food Security Reference List for Animal Agriculture Ecology and Food Security list
- more ecological information is given there
- more ecological information is given there