Do Social Grants Reduce Household Food Insecurity in South Africa: Moderated Mediation Analysis of Income Pathway

South Africa has implemented an extensive social grant system to improve the wellbeing of vulnerable households. However, evidence remains limited regarding the pathways through which social grants are associated with household food insecurity and whether these relationships vary across geographical contexts of South Africa. Understanding these mechanisms is essential for designing more effective and spatially targeted social protection policies. This study examined the relationship between social grant receipt and household food insecurity, hypothesizing that household income serves as the principal pathway linking social grants to food insecurity. This study used nationally representative data from the 2024 General Household Survey. A latent food insecurity index was constructed using a two-parameter logistic Item Response Theory model, and a moderated-mediation structural equation model was employed to decompose the association between social grant receipt and food insecurity into direct and indirect components while accounting for geographic heterogeneity. The results indicate that social grants are strongly targeted toward households with higher levels of food insecurity and lower incomes, confirming that grant recipients are among the most vulnerable households in South Africa. Household income was negatively associated with food insecurity and mediated 55.4% of the total association between social grant receipt and household food insecurity. This underscores income as the main transmission pathway. High geographic heterogeneity was observed. The indirect income-mediated association was strongest in commercial farming areas, followed by urban and rural areas administered by local leaders. The direct association was significant in urban and rural areas administered by local leaders. These results show that the effectiveness of income transfers depends on the household’s demographic and socioeconomic conditions. The findings suggest that although social grants play an important role in reducing household vulnerability, cash support alone is insufficient to address household food insecurity among disadvantaged households in South Africa. Therefore, strengthening income support provided through social grants should be complemented by location-specific interventions that expand employment opportunities, improve market access, promote productive asset accumulation, and strengthen local food systems, particularly in rural areas where constraints continue to limit household food security.