Household Size and Consumption Behavior in the Korean Food Demand System

We estimated an EASI (Exact Affine Stone Index) food demand system in Korea using the quarterly data of the period 2006-2021 to investigate the impacts of the family structure on food expenditures. Family structure variables of the model include family size, household head age, and income sources (wage vs. non-wage). The marginal impacts of these household characteristics as well as those of family income and food preference changes over time were estimated. We identified food preference differences among families with a single member, two members, three members, four members, and five and more members. It is shown that both single-member families and two-member families prefer more fishery products and fruits but less grain, meat, and dairy products than large-sized families. However, those two types of small-sized families revealed preferences on processed foods different from each other. Based on the estimation results, we simulated the changes in food expenditures caused by the simultaneous changes in family size, age, and the proportion of wage earners for the last 15 years. It is shown that the family structure change affected fresh food expenditures more than processed food expenditures. We found that the observed trend of increasing shares of meat and processed foods would have been even strengthened if there had been no changes in the family structure.