Śatapatha Brāhmaṇa ("of a hundred paths") 7.2.2.17

7.2.2.17

tā ubhayyaḥ ṣoḍaśa sampadyante | ṣoḍaśakalaḥ prajāpatiḥ prajāpatiragnirātmaṃsammitamevāsminnetadannaṃ dadhāti yadu vā ātmasammitamannaṃ tadavati tanna hinasti yadbhūyo hinasti tadyatkanīyo na tadavati

Both kinds (of furrows) amount to sixteen,--of sixteen parts Pragâpati consists, and Pragâpati is Agni: he thus puts into him food proportionate to his body. And, indeed, the food which is proportionate to the body, satisfies, and does no harm; but that which is too much, does harm, and that which is too little, does not satisfy.