Alignment in health and environmental impacts of foods

The impacts assessed by the paper were:

• Health
  • Mortality
  • Coronary heart disease
  • Colorectal cancer
  • Diabetes
  • Stroke
• Environmental
  • Acidification potential
  • Eutrophication potential
  • Greenhouse gas emissions
  • Land use
  • Scarcity-weighted water use

The figure below summarises the results as radar plots. Plots where the points are closer to the centre indicate “better” outcomes for that food type when ranked against the other food types (health on the left of each plot, environment on the right of each plot), as seen for (for example) fruits and vegetables. Plots where the points are further from the centre (e.g. unprocessed red meat and processed red meat) indicate that the food type ranks “worse” than the other food types. Some tradeoffs can be seen - for example, the water use of nuts and the relatively high environmental impacts of fish versus its relatively beneficial health impacts.

The authors conclude that dietary changes that reduce health risks would also tend to contribute to meeting sustainability goals since, as shown in the figure below, shifting from unprocessed and processed red meat towards foods such as whole grains, fruits, legumes and nuts would generally reduce both mortality and environmental impacts. Food types of intermediate health and environmental impacts (e.g. dairy, fish and chicken) could also be useful if they replace processed or unprocessed red meat.

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.

Reference

Clark, M.A., Springmann, M., Hill, J. and Tilman, D., 2019. Multiple health and environmental impacts of foods. Proceedings of the National Academy of Sciences, p.201906908.

Read the full paper here. See also a blog post from the LEAP team here: Assessing health and environmental impacts of foods - Small changes made by individuals can improve health and the planet. See the Foodsource resource Which diets generate fewer GHG emissions and other environmental impacts?