From food, verily, are produced whatsoever creatures dwell on the earth.  Moreover, by food alone they live.  And then also into it they pass at the end. Food, verily, is the eldest born of beings.  Therefore it is called the healing herb of all.  ... From food are beings born. When born they grow up by food.  

                                                                                                                                                               Taittiriya Upanisad, Brahmananda valli 

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