SystematicReviewofDietaryPatternsand SustainabilityintheUnitedStates

Abstract

Improvingawarenessandaccessibilityofhealthydietsarekeychallengesforhealthprofessionalsandpolicymakersalike.WhiletheUSgovernment has been assessing and encouraging nutritious diets via the Dietary Guidelines for Americans (DGA) since 1980, the long-term sustainability, and thus availability, of those diets has received less attention. The 2015 Dietary Guidelines Advisory Committee (DGAC) examined the evidence on sustainable diets for the first time, but this topic was not included within the scope of work for the 2020 DGAC. The objective of this study was to systematically review the evidence on US dietary patterns and sustainability outcomes published from 2015 to 2019 replicating the 2015 DGAC methodology. The 22 studies meeting inclusion criteria reveal a rapid expansion of research on US dietary patterns and sustainability, including 8 studies comparing the sustainability of DGA-compliant dietary patterns with current US diets. Our results challenge prior findings that diets adhering to national dietary guidelines are more sustainable than current average diets and indicate that the Healthy US-style dietary pattern recommended by the DGA may lead to similar or increased greenhouse gas emissions, energy use, and water use compared with the current US diet. However, consistent with previous research, studies meeting inclusion criteria generally support the conclusion that, among healthy dietarypatterns,thosehigherinplant-basedfoodsandlowerinanimal-basedfoodswouldbebeneficialforenvironmentalsustainability.Additional researchisneededtofurtherevaluatewaystoimprovefoodsystemsustainabilitythroughbothdietaryshiftsandagriculturalpracticesintheUnited States