Integrating Sustainability and Nutrition through Dietary Pattern Optimization: A Life Cycle Assessment of Canada’s Food Guide

Abstract

An ideal diet should meet nutritional needs, promote health, while have less of an environmental impact. Recent studies have highlighted the significance of environmental impacts of food consumption in the context of climate change. However, research examining the environmental impacts of dietary choices in Canada is limited. The 2019 Canada’s Food Guide (CFG), despite being the official and most authoritative food guide in Canada, does not evaluate its environmental impacts. Furthermore, existing studies on sustainable diets often rely on hypothetical dietary patterns (DPs), lacking real-world data on Canadians' dietary intake.

This study aims to address these gaps by (1) evaluating the environmental impacts and nutritional aspects of dietary patterns (DPs) based on the 2019 CFG for Ontarian adults from linear optimization, (2) comparing the nutrition quality and environmental impacts of these optimized diets with those of Ontario average consumption from the 2015 Canadian Community Health Survey – Nutrition (CCHSN) and National Nutritious Food Basket (NNFB), and (3) exploring the trade-offs between nutrition and multiple environmental impacts. The Nutrient Rich Foods Index 9.3 (NRF 9.3) was applied to assess nutrition quality, and Life Cycle Assessment (LCA) was used to evaluate global warming potential (GWP), eutrophication (EU), and water footprint (WF) from farm to fork.

Results showed that optimized diets significantly reduce meat and dairy intake while increasing plant-based proteins. Optimized diets achieved a 36.1% to 51.1% reduction in GWP (3.2-4.1 kg CO2 eq) and a 34.3% to 54.2% reduction in EU compared to the Ontario average consumption, while maintaining a high nutritional quality. However, the study also identified trade-offs, such as an increased WF due to the higher inclusion of water-intensive foods like nuts. This research contributes to the development of dietary guidelines that align with both human health and planetary boundaries, providing valuable insights for future updates to the CFG and informing policy decisions aimed at fostering healthier and more sustainable food systems. However, the study is limited by the data availability and the focus on specific environmental impact categories. Future studies should explore a broader range of food items as well as environmental indicators, expand to other regions in Canada, and consider the cultural and economic factors that influence food choices. Overall, this research contributes to a more comprehensive understanding of the environmental impacts of food consumption in Canada and supports efforts to promote sustainable food systems.