Energetic closure of the spatially resolved global food system

Abstract

Integrated global food system analysis is hampered by the fragmentation of data among food types, processes, and scales. Studies also often neglect the connection to human metabolism -- the ultimate driver of food demand. Here we use a common energetic framework to harmonize data on 95 individual food commodities across food system processes, including production, processing, animal feed and consumption, and estimate human metabolism from body size, demographic, and activity data. We estimate that the share of unmetabolized food calories globally doubled between 1990 and 2019 (from about 10 to 20% of the total calories available for human consumption) as food supply outpaced energy expenditure. Approximately half (51%) of the global population's metabolic demands could theoretically be met by production in the same local 1-degree grid cell (~ 10,000 km2) when holding diets constant. Our open-source framework can be applied to assess strategies to reduce food system inefficiencies from photosynthesis to metabolism while meeting local energetic demands.