LCA inventory data based on input-output tables was used to analyze the effects of the self-sufficiency rate of food and the food consumption pattern on the CO2 emission in Japan. For the food item i with the total consumption Ci [M¥] and self-sufficiency rate xi, the total amount of carbon emission consists of (1) domestic production of i, (2) production of industrial product j to be exported for the import of i, and (3) transportation to export j and import i. According to this model, an effective carbon emission coefficient, σeff,i was calculated for each food item i to calculate the total amount of carbon emission. Because of the low self-sufficiency rate of food (∼40%) and the rapid change in the food consumption pattern from the traditional to the western style, the total amount of carbon emission was proved to have substantially increased for the consumption of food in Japan. The difference between the present C-emission and that by assuming 100% food self-sufficiency or that assuming the self-sufficiency rate (∼60%) and the food consumption pattern at 1970 was almost comparable with the COP3 goal to reduce CO2 emission. This means that an increase in food self-sufficiency rate and/or a change in food consumption pattern, resulting in the industrial structure change, can be an effective option to reduce CO2 emission in Japan.