Who eats with family and how often? Household members and work styles influence frequency of family meals in urban Japan.

Family commensality, or meals eaten together with family members, is a key practice to understand the socio-cultural organization of eating and family lives. Yet empirical evidence is limited outside of western societies, which have different household structures, work styles, and socio-cultural constructions of the practice. This study examined frequencies of family commensality based on 242 surveys of Japanese adults aged between 20 and 85 in two metropolitan areas. Results showed that family commensality is less frequent not only among those living alone, but also among those living with only non-partners including adult children, parents, and non-family members, than among those living with partners. Full-time employment was associated with late dinner times on weekdays. Later weekday dinner times were strongly associated with reduced frequency of dinners together. Late dinners have become commonplace among full-time workers in postwar Japan, and the peak dinner time in Japan occurs later than in other developed countries. Thus, work and lifestyle constraints impacting schedules appear to influence the frequency of family commensality. Our results suggest that frequencies of family commensality are influenced by co-residents and work styles of participants rather than household sizes. The idea that reduction of household size drives reduction of family commensality may be biased by previous studies conducted in western countries where most people reside in either single or nuclear households. Our study highlights complex determinants of family commensality, beyond presence of other household members, and demonstrates a need for rigorous investigation of family commensality across cultures.