Greenhouse gas emissions, cost, and diet quality of specific diet patterns in the United States

Abstract

BackgroundMajor policy agendas are calling for accelerated investment in research that addresses the impact of diet patterns on multiple domains of sustainability. ObjectivesTo evaluate the comparative greenhouse gas emissions, diet cost, and diet quality of plant-based, low-grain, restricted carbohydrate, low-fat, and time-restricted diet patterns on a daily per capita basis. MethodsDietary data from the National Health and Nutrition Examination Survey (2013–2016, n = 4025) were merged with data on greenhouse gas emissions (GHGEs) and food prices from multiple databases. The Healthy Eating Index-2015 was used to measure diet quality. ResultsThe plant-based diet pattern had the lowest GHGEs [3.5 kg carbon dioxide equivalent (CO2eq); 95% confidence interval (CI): 3.3, 3.8 kg CO2eq] and among the lowest diet cost ($11.51; 95% CI: $10.67, $12.41), but diet quality (45.8; 95% CI: 43.3, 48.5) was similar (P > 0.005) to most other diet patterns. All of the sustainability impacts of the low-grain diet pattern were intermediate. The restricted carbohydrate diet pattern had the highest diet cost ($18.46; 95% CI: $17.80, $19.13) but intermediate diet quality (46.8; 95% CI: 45.7, 47.9) and moderate-to-high GHGEs (5.7 kg CO2eq; 95% CI: 5.4, 5.9 kg CO2eq). The low-fat diet pattern had the highest diet quality (52.0; 95% CI: 50.8, 53.1) and intermediate GHGEs (4.4 kg CO2eq; 95% CI: 4.1, 4.6 kg CO2eq) and diet cost ($14.53; 95% CI: $13.73, $15.38). The time-restricted diet pattern had among the lowest diet quality score (42.6; 95% CI: 40.8, 44.6), had GHGEs similar to most other diet patterns (4.6 kg CO2eq; 95% CI: 4.2, 5.0 kg CO2eq), and low-to-moderate diet cost ($12.34; 95% CI: $11.38, $13.40). ConclusionsMost diet patterns are associated with sustainability trade-offs. The nature of these trade-offs can help inform discussions on food and nutrition policy in the United States, including the National Strategy on Hunger, Nutrition, and Health, and future Dietary Guidelines for Americans.