Carbon Footprints of Dietary Patterns in Ontario, Canada: Insights for Creating Sustainable and Nutritionally-Balanced Diets

The current global food system, from production to consumption, is estimated to contribute to 30% of global greenhouse gas emissions, to use 70% of available fresh water, and to cause up to 80% of deforestation. With increasing income and wealth, our eating habits have shifted towards diets that are high in animal-based products and have high-sugar content, resulting in overconsumption of calories and protein. These changes are contributing to increasing rates of obesity and non-communicable diseases, such as diabetes, cancer, and cardiovascular disease. Projected increases in population and income are expected to exacerbate health and environmental burdens. Thus, it is crucial to understand how to shift towards dietary patterns that are nutritionally-balanced and reduce environmental impacts. Many studies have assessed the environmental impacts of food consumption in various countries and regions, but have been mostly focused in Europe. Impacts have been evaluated based on a snapshot of food consumption, i.e. on a day, month or year basis. As people’s dietary patterns can change over time, it is important to understand historical and current food consumption to determine which factors reduce environmental impacts. Thus, the purpose of this research is to evaluate the changes in Ontarians’ food consumption, nutritional profile, and carbon footprint of dietary patterns over 10 years. We formulated representative dietary patterns by considering actual food intake data for up to 10,000 Ontarian residents from the Government of Canada’s 2004 and 2015 Canadian Community Health Survey. We used Life Cycle Assessment to quantify environmental impacts of the dietary patterns, from production to consumption. We also considered food waste along the food supply chain. Preliminary findings show that Ontarians are shifting from red meat to chicken and fish, and are consuming more dark-green vegetables and fresh fruits and less food products with high-level sugar content, such as sweets, soft drinks, and alcoholic beverages. These changes have resulted in small reductions in the carbon footprint of most dietary patterns, but more drastic dietary shifts are needed to reduce the carbon footprint of dietary patterns. Because Ontarians are not eating a nutritionally-balanced diet, we also present the carbon footprint of nutritionally-balanced representative dietary patterns based on Canada’s Food Guide and the Harvard Healthy Eating Plate. This research could be helpful to inform: i) decision-makers, government bodies, and nutritionists to find new strategies to shift food consumption towards low carbon-intensive food choices; ii) agriculture policy-makers for optimizing natural resource use; iii) food businesses to promote food products high in nutrients and low in carbon footprint; and iv) consumers on how to reduce their carbon footprint while achieving a nutritionally-balanced diet. Further work is needed in three main areas to have a holistic understanding on sustainable food consumption and production: 1) understanding societal factors that have resulted in the changes in main food categories, 2) identifying barriers in reducing food waste along food supply chain, and 3) assessing other environmental impacts, such as water footprint and biodiversity loss.