The present invention relates to the healthy supplementary foods and the technology for making them by enabling the efficient collection of young leaves of rice plant rich in nutrition and processing without losing nutrition characteristic of young leaves of rice plant. Collection of young leaves of rice plant consists in cutting young leaves 2 of the upper side only while leaving the below part of the rice plant when rice plant has grown so old as to be in ears or just before this, allowing for cutting the remaining young leaves after they have grown again after passing a certain period of time. This step will be repeated several times. The young leaves 2 cut out will be pre-processed appropriately like cleaning before they are far infrared dried to contain a given volume of water, thus refraining, for instance, the destruction of the useful compounds in the young leaves 2 of rice plant. The first processed food after being far infrared dried may be preserved, pulverized or put to other appropriate processes to make the desired processed food 4 or other foods.
