Integrating emergy theory and food security: An examination of the emergy exchange ratio

Food security is often linked to economic exchange, but it involves broader dynamics and can also be achieved through non-market pathways. Recognizing this complexity, the Emergy Exchange Ratio (EER) was proposed—a ratio between the emergy of food acquired and that of money spent—as a complementary indicator to assess food security. In this study, we examined the relationship between the EER and the four dimensions of food security using indicators from the Global Food Security Index (GFSI). Machine learning models, particularly Ridge Regression, were employed to predict EER values for Brazil from 2012 to 2022. The Ridge model showed strong performance (R² = 0.89; MAE = 0.035), indicating good explanatory power. Among 25 GFSI indicators, “food security and access policy commitments” (∼16 %) and “sufficiency of supply” (∼14 %) were the top predictors of EER variation. These results suggest that the EER is sensitive to public policies and food supply dynamics, indicating its relationship with food security. Limitations include the focus on Brazilian data and data quality constraints. Still, EER offers a systemic, biophysical lens on food access grounded in Odum’s emergy theory.