Eutrophication potential of food consumption patterns.

Although the environmental impacts and carbon footprints of foods are gaining more public attention and scientific debate, few studies have systematically evaluated the life cycle nitrogen and phosphorus flows among different food types. Disruption of natural nitrogen and phosphorus cycles already result in serious environmental quality degradation and economic losses, such as loss of fisheries due to hypoxia in the Gulf of Mexico. This study characterizes the nutrient flows during food production, processing, packaging, and distribution stages for eight food types; compares carbon footprints and nitrogen equivalent footprints of food groups; evaluates solutions to reduce excessive nitrogen outputs; and estimates effectiveness and efficiency of possible solutions. Different food groups exhibit a highly variable nitrogen-intensity; on average, red meat and dairy products require much more nitrogen than cereals/carbohydrates. The ranking of foods' nitrogen footprints is not consistent with their carbon footprints. For example, dairy products and chicken/eggs have relatively high nitrogen footprint and low carbon footprints. Finally, the study evaluates shifting food consumption patterns. Dietary shifts from dairy products and red meat to cereals can be an effective approach for lowering the personal nitrogen footprint.