Food Security in Mega-Countries: Quantity, Nutrition, and Ecology in a Shape Constrained Generalized Additive Model Framework

The growing human population poses severe challenges to food security, yet research on food security in the most populous countries, also known as mega-countries, remains limited. This study analyzes the spatiotemporal evolution of food security in mega-countries through the lenses of quantity, nutrition, and ecological security. A Shape Constrained Generalized Additive Model is employed to explore the nonlinear relationship between population size and food security, and to project future trends in food security among mega-countries. The results show that from 2001 to 2022, quantity security improved substantially, followed by nutrition security, while ecological security showed a declining trend. Disparities in food security across mega-countries have also widened. The relationship between population size and food security is nonlinear in various dimensions. Under our assumptions, food security is projected to decline in export-oriented mega-countries but improve in import-oriented ones. While urbanization tends to enhance food security, population aging may intensify food system pressures.