Markandeyapurana 34.27

34.27

prāṅmukhodaṅmukho vāpi svācānto vāgyataḥ śuciḥ /
bhuñjītānnañca taccitto hyantarjānuḥ sadā naraḥ //

“Moreover a householder should do reverence to the pitṛs, gods and mankind, and to living creatures, according to his capability, and afterwards eat himself. And a man should always eat his food, facing the east or the north, with his mouth well rinsed out, restraining his speech, pure, with his mind intent on his food and with his face between his knees.