Impact of a College Course on the Sustainability of Student Diets in Terms of the Planetary Boundaries for Climate Change and Land, Water, Nitrogen and Phosphorus Use

Victoria A Whitener,Paula Karyn Nguyen,Brian Cook,Ingrid Spielbauer,Jennifer A Jay

doi:10.3389/fsufs.2021.677002

Victoria A Whitener, Paula Karyn Nguyen + Show 3 more

Open Access

https://doi.org/10.3389/fsufs.2021.677002

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Abstract

While it is widely acknowledged that shifts in diet could play a large role in mitigating climate change with important health co-benefits, knowledge on how to accomplish these shifts is lacking. Our previous study showed a statistically significant reduction in the dietary carbon footprint of students who had completed a college course on the connections between food and the environment compared to a control group enrolled in an unrelated course. An extension of the previous study, this research evaluates the sustainability of female and male diets in both the intervention and control groups from baseline to follow up with respect to the following planetary boundaries: greenhouse gases, land use, water use, nitrogen loss, and phosphorus use. In addition, a 50-point modified Alternative Healthy Eating Index was calculated at baseline and follow up for all students. Female students enrolled in the intervention course reported diets with statistically significant reductions in their footprints from baseline to follow up for greenhouse gases (p = 0.011), land use (p = 0.012), and phosphorus (p = 0.045), and the female diets were statistically different from the control groups for those three boundaries. For water use, female diets increased in footprint from baseline to follow up due to an increase in vegetable intake. Males enrolled in the intervention showed similar trends (reductions in footprints for greenhouse gases, land use, and phosphorus use and an increase in blue water use), but differences were not statistically significant, partially due to the smaller number of male respondents. Student dietary footprints are compared to a per capita limit allowable for food according to the planetary boundaries concept. For all of the planetary boundaries except blue water use, the student dietary footprints were well above the per capita boundary for food-related sources.

Highlights

Society is facing both critical environmental challenges and increases in non-communicable diseases that are already diminishing the quality of life for much of the global population and are on track to worsen
Using the same dietary survey dataset in Jay et al (2019), we extend the previous work by: 1) comparing the carbon, nitrogen, phosphorus, water, and land use footprints for the students in the intervention and control groups at baseline and follow up; 2) comparing the dietary environmental footprints to per capita planetary boundaries; 3) quantifying impacts of the course on a modified 50 point Alternative Healthy Eating Index; and 4) investigating the relationships between the modified AHEI and the environmental footprints for various groups of students
To test the hypothesis that education in food and sustainability resulted in lower dietary environmental footprints, student surveys from before and after the Food and Cosmos classes were used to calculate CO2−eq, water use, N, P, and land use footprints of the student diet (Figures 1–5)

Summary

Introduction

Society is facing both critical environmental challenges and increases in non-communicable diseases that are already diminishing the quality of life for much of the global population and are on track to worsen. A recent paper found that even if all fossil fuel emissions were halted immediately, food-related greenhouse gas emissions only would exceed the allowable limit if we are to avoid disastrous climate change (Clark et al, 2020). This is in accord with other work demonstrating that dramatic changes in food demand are necessary for climate stability (Hedenus et al, 2014; Bryngelsson et al, 2016)

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