The present invention relates to a system for diet control; more specifically, to an autonomous portable electronic device, which allows the user easily, input a nutrition facts data about the food he or she takes into the device. The device can extract, display, and store in a cumulative fashion the nutrition facts he or she takes, and possibly give a warning message when the user takes more nutrition facts than their needs, and possibly give a suggestion helping the user to select to meal. Also, the device can easily send the user's nutrition information to the restaurant/food store when they buy the food so the restaurant/food store can make the food based on the user's nutrition requirement. Also, the device can count the energy consumed by the user, and give the user a hint on how to adjust his or her nutrition/diet control.