Greenhouse Gas Emission Estimates of U.S. Dietary Choices and Food Loss

Summary

This meta-analytic study quantified the greenhouse gas footprint of the U.S. food system, finding that food losses at retail and consumer levels account for 28% of diet-related emissions, equivalent to 33 million vehicle-years annually. Beef production, despite representing only 4% of the retail food supply by weight, contributed 36% of diet-related GHG emissions. A shift to USDA dietary recommendations without caloric adjustment would increase GHG emissions by 12%, whereas a calorically adjusted shift aligned with population needs would reduce emissions by only 1%.

Regional applicability

Findings are specific to the United States food system and dietary patterns. The study provides a methodological framework applicable to UK dietary assessment, though UK emission factors, food availability data, and dietary recommendations differ; the paper underscores the need to integrate environmental costs into dietary guidance formulation—directly relevant to UK nutrition policy and sustainability agendas.

Key measures

Greenhouse gas emissions (kg CO₂-eq per capita per day); proportion of total diet-related emissions by food type; percentage change in diet-related GHG emissions under different dietary scenarios

Outcomes reported

The study quantified greenhouse gas emissions associated with food loss at retail and consumer levels, and modelled the GHG impact of shifts toward USDA dietary recommendations versus the current average U.S. diet.

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