Abstract
Food choices are shifting globally in ways that are negatively affecting both human health and the environment. Here we consider how consuming an additional serving per day of each of 15 foods is associated with 5 health outcomes in adults and 5 aspects of agriculturally driven environmental degradation. We find that while there is substantial variation in the health outcomes of different foods, foods associated with a larger reduction in disease risk for one health outcome are often associated with larger reductions in disease risk for other health outcomes. Likewise, foods with lower impacts on one metric of environmental harm tend to have lower impacts on others. Additionally, of the foods associated with improved health (whole grain cereals, fruits, vegetables, legumes, nuts, olive oil, and fish), all except fish have among the lowest environmental impacts, and fish has markedly lower impacts than red meats and processed meats. Foods associated with the largest negative environmental impacts—unprocessed and processed red meat—are consistently associated with the largest increases in disease risk. Thus, dietary transitions toward greater consumption of healthier foods would generally improve environmental sustainability, although processed foods high in sugars harm health but can have relatively low environmental impacts. These findings could help consumers, policy makers, and food companies to better understand the multiple health and environmental implications of food choices.
Generated Summary
This study investigates the multifaceted impacts of food choices on both human health and the environment. It employs a comprehensive approach, examining how the consumption of 15 different food groups is associated with 5 health outcomes and 5 environmental degradation aspects. The research utilizes meta-analyses of dose-response relationships and life cycle assessments (LCAs) to quantify these impacts. The core methodology involves analyzing the effects of consuming an additional serving per day of each food group on health outcomes (type II diabetes, stroke, coronary heart disease, colorectal cancer, and mortality) and environmental aspects (GHG emissions, land use, water use, acidification, and eutrophication). The study aims to provide insights for consumers, policymakers, and food companies to make informed decisions, supporting international sustainability targets such as the UN’s Sustainable Development Goals and the Paris Climate Agreement.
Key Findings & Statistics
- The study examined the impact of 15 food groups on 5 health outcomes and 5 environmental outcomes.
- Food production emits approximately 30% of global greenhouse gasses (GHGs).
- Agricultural land use occupies approximately 40% of Earth’s land.
- Poor dietary quality is a risk factor for 9 of the top 15 global morbidity risk factors.
- Consumption of an additional serving per day of each of 15 foods is associated with 5 health outcomes in adults and 5 aspects of agriculturally driven environmental degradation.
- Foods associated with a larger reduction in disease risk for one health outcome are often associated with larger reductions in disease risk for other health outcomes.
- Foods with lower impacts on one metric of environmental harm tend to have lower impacts on others.
- Of the foods associated with improved health (whole grain cereals, fruits, vegetables, legumes, nuts, olive oil, and fish), all except fish have among the lowest environmental impacts, and fish has markedly lower impacts than red meats and processed meats.
- Foods associated with the largest negative environmental impacts—unprocessed and processed red meat—are consistently associated with the largest increases in disease risk.
- Consuming an additional serving per day of the 7 foods (nuts, whole grains, fruits, vegetables, legumes, olive oil, and fish) is associated with a significant reduction in risk for 20 of the 34 health endpoints.
- The Spearman rank-order correlations showed that a food group that benefitted or harmed one health metric tended to have similar affects on the other health metrics.
- 8 of 10 Spearman correlations were significant and positive (P < 0.05)
- Nuts, minimally processed whole grains, fruits, vegetables, legumes, olive oil, and fish are associated with significantly (P < 0.05) reduced mortality and/or reduced risk for one or more diseases.
- Consuming an additional serving per day of the 7 foods is associated with a significant reduction in risk for 20 of the 34 health endpoints for these foods and no significant change in disease risk for 14 of 34 health outcomes.
- Daily consumption of an additional serving of dairy, eggs, and chicken is not significantly associated with disease incidence for 12 of the 14 health endpoints.
- Consumption of sugar-sweetened beverages, unprocessed red meat, and processed red meat are consistently associated with increased disease risk.
- Sugar-sweetened beverage consumption is associated with a significant increase in CHD, type II diabetes, and stroke.
- Consumption of unprocessed and processed red meat is associated with significant increases in disease risk for all 5 health outcomes examined.
- A daily serving of processed red meat is associated with the largest mean increase in risk of mortality and incidences of CHD, type II diabetes, and stroke.
- The mean GHG emissions, land use, acidification, and eutrophication per serving of food produced for the 15 food groups differed by 2 orders of magnitude.
- Unprocessed red meat had twice the water impact of dairy, nuts, processed red meat, and olive oil.
- Foods that have a low mean relative environmental impact per serving for 1 environmental indicator often also have low mean relative environmental impacts for the other 4 environmental indicators.
- Minimally processed plant source foods, olive oil, and sugar-sweetened beverages consistently have among the lowest environmental impacts for all indicators, often having a relative environmental impact of less than 5 for all 5 environmental indicators.
- Producing a serving of unprocessed red meat has the highest impact for all 5 environmental indicators, with a relative environmental impact ranging from 16 to 230.
- Producing a serving of processed red meat has the second highest mean impact on acidification, GHG emissions, and land use and the third highest mean impact for eutrophication.
- Whole grain cereals, fruits, vegetables, nuts, and olive oil have an AREI of 4 or less per serving.
- Fish, the other food group that is associated with a significant reduction in mortality, has an AREI of 14 per serving.
- Unprocessed red meats (AREI = 73) and processed red meats (AREI = 37) have the highest AREIs while sugar-sweetened beverages (AREI = 0.95) have the lowest AREIs of all foods in this analysis.
Other Important Findings
- Foods associated with improved adult health (whole grain cereals, fruits, vegetables, legumes, nuts, olive oil, and fish) often have low environmental impacts.
- The same dietary transitions that would lower incidences of noncommunicable diseases would also help meet environmental sustainability targets.
- Foods associated with improved adult health also often have low environmental impacts, indicating that the same dietary transitions that would lower incidences of noncommunicable diseases would also help meet environmental sustainability targets.
- Dietary transitions towards greater consumption of healthier foods (whole grain cereals, fruits, vegetables, legumes, nuts, olive oil, and fish) would generally improve environmental sustainability.
- The health outcomes reported here are the relative risks (RRs) of disease resulting from consuming an additional serving of a food per day relative to the average intake of that food observed in a cohort study.
- The health outcomes reported here were estimated by tracking the dietary patterns and health outcomes of tens of millions of individuals.
- The health outcomes reported here control for body mass index.
- The mean GHG emissions, land use, acidification, and eutrophication per serving of food produced for the 15 food groups differed by 2 orders of magnitude.
- The general pattern, and the large variation around the mean scarcity-weighted water use, merits further exploration.
- Foods that have a low mean relative environmental impact per serving for one environmental indicator often also have low mean relative environmental impacts for the other four environmental indicators.
- The variation around the mean health and environmental impacts can result from differences among foods within each food group, food preparation, or production methodology.
- Producing a serving of unprocessed and processed red meats has environmental impacts 10 to 100 times larger than those of plant source foods for GHG emissions, land use, acidification, and eutrophication.
- The health benefit of consuming a second additional serving per day is often smaller than the health benefit of consuming the first additional serving per day.
Limitations Noted in the Document
- The study acknowledges that the health outcomes reported are most relevant and applicable to individuals whose diets and lifestyles are similar to those typically found in higher-income regions.
- The health estimates reported here control for body mass index.
- The inability to fully control for potential dietary confounders (e.g., reduced consumption of red meat when chicken consumption increases) likely influences the observed associations between consumption of chicken and disease risk in particular, and between food consumption and health outcomes more generally.
- The study does not include the potential health implications of consuming an additional serving of one food without reducing consumption of another food (i.e., thereby leading to increased calorie intake and possibly weight gain).
- Health analyses using different methodologies have linked consumption of trans fats and ultraprocessed foods with increased disease risk, but these foods were not included in the dose-response metaanalyses.
- The study’s environmental data primarily come from LCAs, and there could be variation in the environmental impacts of food production across regions.
Conclusion
The study’s findings highlight the interconnectedness of food choices, human health, and environmental sustainability. The research demonstrates that dietary shifts towards foods associated with improved health outcomes often coincide with lower environmental impacts. Specifically, diets rich in whole grains, fruits, vegetables, legumes, nuts, olive oil, and fish not only reduce the risk of noncommunicable diseases but also contribute to environmental sustainability goals. The results suggest that dietary transitions could reduce the risk of diet-related noncommunicable diseases and help meet international sustainability targets. The study highlights the importance of considering both health and environmental factors when making food choices and formulating food policies. Furthermore, the research indicates that food consumption and production are linked with other aspects of human health and environmental degradation. These results underscore that improving food systems could yield multiple health and environmental benefits globally, highlighting the potential of public and private solutions to shift food consumption toward healthier and more environmentally sustainable outcomes.
IFFS Team Summary
- Article demonstrates that healthy plant based foods are concurrently beneficial for the environment and health
- Note regarding fish:
- This paper ONLY considers eutrophication (a consequence of land based ag) and acidification (a consequence of climate change)
- Does not consider the biodiversity impact of massive fishing, plastic waste from fishing, by-kill of non target fish and other species, etc …
- the article misses the massive impact of fishing on the ocean biome