Q. must one face the qibla while eating?
A. To intentionally face ones back towards the qibla is not good whilst eating, more so when an alternate choice exists. To impose the facing of qibla would be just as wrong.
Often we are not able to face qibla whilst eating. To face the qibla would be a hardship in public settings or even at home when attempting to have a face to face conversation. It would also be highly un-social. Eating should promote cordial relations within the parameters of religion! Thus, to force oneself to always face the qibla would cause hardship on oneself and that would be unnecessary.
Under conditions of full choice and minimum difficulty, it would be nice to face qibla. It would not be requirement. We cannot bind what sharia has not bound upon us.
Allah Certainly Knows Best.