In Japan, the continuous reduction in family size during the post-war period has caused a decline in the efficiency of domestic production in households. The proportion of expenditure on foodstuffs for homemade meals in total food expenses has decreased; on the other hand, the proportion of expenditure on convenience foods (cooked food, fast food, etc.) and eating-out has increased. The changes in the diet of Japanese people prevent the household consumption of domestic agricultural products. The objective of this study is to provide a baseline about food consumption from the viewpoint of the household demand-side and to find a measure, which acts as a brake on the decrease in the household consumption of domestic agricultural products. The main outcomes of this study are as follows. First, the changes in the dietary habits of Japanese households during the post-war period depend on the economic factors associated with Japanese economy at that time in spite of dietetic issues. Second, the household consumption of domestic agricultural products is going to decline if we maintain the same conditions. Third, an improvement in the efficiency of domestic agricultural production is essential for keeping the volume of household demand for domestic products since progress in the efficiency of homemade meals is difficult for today's households. This is the measure of cooperation between households and domestic agriculture the study suggests.