The purpose of this study is to propose that the indices for the sustainability of food should be determined by the environmental efficiency which is the ratio of the Life Cycle carbon dioxide emission (environment load) of food and the total evaluation of food value. The environmental efficiency indices in the food research field are derived from dividing the evaluation of food value by the environment load. In the study, the environmental load (Life Cycle carbon dioxide emission) produced from cooking certain food and menu was compared with the food value obtained from them. The actual measurement of Life Cycle C02 emission of the food was conducted, and an ecoefficiency indices of food were calculated from quantified environmental load and food value evaluation. First, the evaluating factor of food was selected for the practical use of the environmental efficiency index. Its value was used as the numerator of the function for calculating the environmental efficiency. Next, food menu for evaluation was selected and created. Then, the environmental load was measured. The evaluating factor was assumed to be a nutritive evaluation of food. The nourishment evaluation items include energy, protein, lipid, calcium, iron, vitamin A, vitamin C, dietary fiber, salt, and vegetable. The denominator of the function for calculating the environmental efficiency is the environment load of the food. The environmental load was assumed by calculating C02 emissions per meal from the stages of producing, transporting, cooking and disposing. It became clear that the environmental efficiency indices provide important information in order to continue a sustainable food lifestyle as considering the environment without ruining health effect or taste of food.