Greenhouse gas emissions in the food system: Current and alternative dietary scenarios

BACKGROUND: There is a growing interest in diets due to the high contribution to greenhouse gas emissions (GHGE). OBJECTIVE: The study was aimed to estimate the impact on GHGE of replacing the current diet with eight alternative diets, which would be associated with GHGE, to contribute to the discussion of how dietary changes affect the GHGE. METHODS: The latest National Nutrition and Health Survey was utilized to determine the nutrient composition of Turkey’s current diet, with eight dietary scenarios designed to meet the National Dietary Guidelines. RESULTS: The current diet had the highest GHGE with 3254.50 g CO2eq/person/day with beef, lamb, and cheese products accounting for the majority of emissions (18.61%, 17.15%, and 10.89%, respectively). The Model diet had a GHGE of 2994.18 g CO2eq/person/day, whereas vegetarian diets had the lowest (lacto-ovo vegetarian diet with 1944.95 g CO2eq/person/day and vegan diet with 1166.80 g CO2eq/person/day). Low energy efficiencies were associated with high diet-related GHGE levels. CONCLUSION: When evaluating future dietary guidelines for a sustainable diet, our study highlighted the need of integrating both health and environmental aspects. The present study found that dietary changes would significantly contribute to lowering GHGE. These findings will be beneficial in informing Turkey’s nutrition, agriculture, and public policymakers.