Be the first to stop eating, for the sake of good manners, and do not be insatiable, lest you give offense: The idea here is to eat moderately and then stop. The translation must not leave the impression that you should stop first because you can’t hold any more. Contemporary English Version has a helpful alternative model:

• Show good manners;
stop eating before others do.
If you keep on eating,
they will be offended.

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on Sirach. (UBS Helps for Translators). New York: UBS, 2008. For this and other handbooks for translators see here.