The impact of nutritional choices on global warming and policy implications: examining the link between dietary choices and greenhouse gas emissions

Research over the past 10 years has illustrated an important connection between dietary choices, the food systems required to produce them, and the subsequent impact on greenhouse gas (GHG) emissions. Several recent studies have used data on the GHG contribution of different food types to model the impact of different dietary patterns on GHG emissions; these studies have most commonly compared the average diet for a particular country to healthier dietary options and vegetarian options. We present a systematic review of this research that models different dietary choices and the associated GHG emissions with the main aim in this paper of contrasting the research implications for policy and practice. A database search of CINAHL, ScienceDirect, Scopus, Web of Science, ProQuest, Cochrane Database of Systematic Reviews, and Mednar in July 2014 identified 21 primary studies modeling the GHG emissions related to a dietary pattern published since 1995. Diets containing a higher ratio of plant to animal products were generally associated with lower GHG emissions; however, the results varied across countries and studies, as did the recommendations by the study authors. Some authors proposed leading with health messages that have a dual environmental gain, whereas others proposed messaging around environmental impact. These inconsistencies in recommended approaches to reduce diet-related GHG emissions relate not just to differences in research findings but also to assumptions about community and political support for action, and there is little empirical evidence on community knowledge, attitudes, and behavioral intention at present to support these recommendations. The paper concludes with a commentary on the policy implications and the need for further research on how to frame the issue so as to garner community and political support to address the leading recommendations of this research. Keywords: diet, climate change, policy