Comparing environmental impacts and diet quality in individual diets

An individual’s food choices largely contribute to both their environmental impact1 and their diet quality2, but little is known about the relationship between the two3. We investigate how these food choices are influenced by an individual’s dietary pattern preferences, gender, and culture, and how these shape someone’s environmental impacts and their beneficial and discouraged nutrient intakes.

Relationship between Environmental Impacts and Nutrition

We compared the environmental impacts (for climate change, water scarcity footprint, and biodiversity loss) of the daily food intake of over 1400 individuals throughout Europe with their daily nutrient consumption based on data collected through the Food4Me study4. Though there was a wide range of eating patterns, nutrient intake, and impacts among individuals, countries and genders, in general it was found that there was good correlation between environmental impacts and kilocalorie intake, especially for climate change and water scarcity footprint (r2 = 0.66 and 0.63, respectively). The relationship was less clear when comparing beneficial nutrient intake and environmental impacts (r2 = 0.23 for climate change) – individuals consuming adequate amounts of beneficial nutrients daily had climate change impacts ranging from 4 to 20 kgCO2 equivalents per day. Those with high beneficial nutrient intake and lower than average impacts (less than 6.1 kgCO2 equivalents per day) tended to consume less meat, dairy, and sweets than others with high beneficial nutrient intakes. The relationship between climate change impacts and high intakes of discouraged nutrients (saturated fat, sugar, and sodium) and increased climate change impacts were correlated (r2 = 0.54).

Variations in Dietary Patterns, Gender, and Country

We found that women, on average, had lower impacts per kilocalorie than their male counterparts, largely due to their considerably lower red meat consumption (which is associated with higher environmental impacts compared to other foods5) and higher fruit and vegetable consumption compared to men. However, men did have slightly higher beneficial nutrient intake compared to women, meaning they were more likely to meet the required beneficial nutrient recommendations. Vegetarians, while having lower than average impacts, did also have a tendency to consume inadequate beneficial nutrients. Diets in which no red meat was consumed had both lower than average impacts while also maintaining an average beneficial nutrient consumption. Differences between countries were large for both impacts and nutrient consumption, and a higher impact diet did not necessarily equal higher nutrient intake (as shown with Spanish subsets), as a higher nutrient intake diet did not mean statistically higher impacts (Irish subsets).

Best Practice Diets

Based on the eating patterns of the population investigated here, in order to achieve a good quality (which was a combination of adequate beneficial nutrient intake as well as low intakes of discouraged nutrients), low impact (in all three impact categories investigated) diet, intakes of meat, sweets, fats, and drinks should decrease (between 37 and 66%), and vegetable and cereal intakes should increase by 60% and 65%, respectively. Research showed that impact reductions are more limited, but still possible, in people already eating good quality diets (high beneficial nutrient intake and low harmful nutrient intake), and they had an average climate change impact of 5.1 kgCO2 equivalents. Individuals with poor quality diets (high discouraged nutrient intake) tended to have higher impacts than average (8.6 kgCO2 equivalents). Individuals with poor quality diets should focus on reducing their intakes of many food groups (meats, sweets, drinks, etc.), while also increasing their intakes of fruits, vegetables, and cereals. This would lead to not only a reduction in their impacts, despite an increased intake in some foods, but also lead to better quality diets.

  1. Tukker, A. et al. Environmental impacts of changes to healthier diets in Europe. Ecol. Econ. 70, 1776–1788 (2011).
  2. WHO/FAO. Globalization, Diets and Noncommunicable Diseases. World Heal. Organ. 1–185 (2003). doi:9241590416
  3. Heller, M. C., Keoleian, G. A. & Willett, W. C. Toward a life cycle-based, diet-level framework for food environmental impact and nutritional quality assessment: A critical review. Environ. Sci. Technol. 47, 12632–12647 (2013).
  4. Celis-Morales, C., Livingstone, K. M. & Marsaux, C. F. M. Design and baseline characteristics of the Food4Me study: a web-based randomised controlled trial of personalised nutrition in seven European countries. Genes Nutr. 10, (2015).
  5. Westhoek, H. et al. Food choices, health and environment: Effects of cutting Europe’s meat and dairy intake. Glob. Environ. Chang. 26, 196–205 (2014).