Evaluating Environmental Footprints of Diet Consumption Patterns- Comparing Nitrogen Footprints and Carbon Footprints of Different Foods

Food supply has become an important contributor to the depletion of natural resources and water quality degradation. Excessive nutrients exported from farming and food processing activities already has resulted in serious hypoxia and eutrophication issues in surrounding ecosystems. Changing food consumption patterns offers a unique opportunity for consumers to lower their personal environmental footprints. Concerned consumers are calling for mitigating environmental burden of food supply. Policymakers and producers therefore require scientifically defensible information about food products and production systems. Recently, significant public concern and scientific attention to environmental impacts of foods mainly focused on their Carbon footprints, few studies have systematically compared the life cycle nutrients flows among different food types. The study of nitrogen and phosphorus inventories for food categories and the potential of reducing nitrification through shifting food consumption patterns have not yet been addressed. Comprehensive comparison of both of carbon footprints and nitrogen footprints over all food categories have not found yet. This study utilizes a life cycle assessment (LCA) approach to quantify the nitrogen flows during food production, processing, packaging and distribution stages over main food types. This study identifies nitrogen footprints of food supply chains among main food categories, compares carbon footprints and nitrogen footprints of different food consumption patterns, and analyzes potential environmental and economic impacts of food consumption shifts. Results show that different food groups exhibit a largely variable nitrogen-intensity. While red meats exhibit the highest nutrient intensity among all food categories, cereals/carbohydrates has the lowest eutrophication potential. Dietary shifting from red meat to cereals/carbohydrates may be an effective way to mitigate eutrophcation impacts resulting from food consumption.