Does Poverty Explain All? A Path Analysis of Single Mothers’ Dietary Behaviors in Japan

Background/Objectives: In Japan, single mothers face a high risk of poverty and poorer dietary quality than partnered mothers; however, the pathways underlying these disparities remain unclear. This study examined whether economic status mediates the association between family structure and maternal dietary behaviors and whether intergenerational co-residence modifies these pathways. Methods: Using nationally representative repeated cross-sectional survey data from 2018 to 2022 (N = 1319 mothers), we conducted path analysis of dietary awareness and behaviors. Family structure was classified as partnered mothers (reference), single mothers not co-residing with grandparents, and single mothers co-residing with grandparents. Economic status and frequency of shared family dinners were modeled as mediators. Results: Compared with partnered mothers, both groups of single mothers showed poorer economic conditions, with greater disadvantage among those not co-residing with grandparents. Economic conditions accounted for substantial disparities in multiple dietary outcomes. Shared family dinners were positively associated with several dietary behaviors; however, dinner frequency did not differ significantly between partnered and single mothers or between single mothers with and without grandparental co-residence. Single mothers not co-residing with grandparents showed residual direct disadvantages in nutritionally balanced meals, breakfast frequency, and healthy dietary awareness, whereas those co-residing with grandparents showed weaker disadvantages. Conclusions: Dietary vulnerability among single mothers in Japan was strongly associated with economic disadvantage, but not poverty alone. Intergenerational co-residence was associated with weaker disadvantage rather than eliminating it. Policies should combine income support with childcare assistance and low-burden Shokuiku or community-based meal support to strengthen resource capacity and daily healthy eating routines.