Start with Psalms 141.
Verse 4 is (NIV):
Let not my heart be drawn to what is evil, to take part in wicked deeds with men who are evildoers; let me not eat of their delicacies.
MT:
אַל תַּט לִבִּי לְדָבָר רָע לְהִתְעוֹלֵל עֲלִלוֹת בְּרֶשַׁע אֶת אִישִׁים פֹּעֲלֵי אָוֶן וּבַל אֶלְחַם בְּמַנְעַמֵּיהֶם
Verse 6:
their rulers will be thrown down from the cliffs, and the wicked will learn that my words were well spoken.
נִשְׁמְטוּ בִידֵי סֶלַע שֹׁפְטֵיהֶם וְשָׁמְעוּ אֲמָרַי כִּי נָעֵמוּ
This psalm is a prayer not to be dependent for sustenance on strongmen, gangsters. The key phrase in verse 4 is וּבַל אֶלְחַם. In this phrase the word לחם, usually a noun meaning sustenance or bread is used as a verb - I shouldn't have to bread with them, i.e. be dependent on them for sustenance.
In verse 6 the key word is שופטיהם, usually translated as judges, as in the book of Judges, but meaning a strongman who rules by force.
Returning to Proverbs 23:1,
When you sit down to dine with a ruler, Consider carefully [a]what is before you
MT:
כִּי תֵשֵׁב לִלְחוֹם אֶת מוֹשֵׁל בִּין תָּבִין אֶת אֲשֶׁר לְפָנֶיךָ
וְשַׂמְתָּ שַׂכִּין בְּלֹעֶךָ אִם בַּעַל נֶפֶשׁ אָתָּה
The initial word כי has a wide range of meanings, of which one of the most common is "if". That is, many conditional verses in the MT start with כי.
So verse 1 also means, "If you [choose] to sit to eat with person of authority, then...
The word שב means "sit", but it also means "to dwell with".
Note that the same verb form of "bread" used in Psalms 141 is used in this verse also, לִלְחוֹם, here in the infinitive, suggesting continued or habitual action.
The word מושל means someone who rules, which was, in the Iron Age, usually a person who had no compunction about using force and was not usually bound by liberal sensibilities or any ideas about the rule of law.
So the sense of this verse to the Hebrew reader rendered into modern English is,
If you choose to take your place at the table of a lord, if you are a sensitive person, you had better consider carefully what you are doing - putting a knife in your throat.
The phrase אִם בַּעַל נֶפֶשׁ אָתָּה, "if you are a person with a soul" (נפש is "soul") is placed at the end of the verse as a literary device and is not a semantic continuation of the previous phrase "put a knife to your throat". This conditional אם, "if", of the final phrase is a counterbalance to the conditional כי at the start of the verse.
The translation "If you are a man of great appetite" is probably a carryover from the medieval commentators and is not based on a good understanding of how phrase order is used as a literary device in the MT. The use of "appetite" to translate נפש is post-MT usage.
In both Psalms 141 and Proverbs 23 we see examples of the great antagonism and suspicion of the writers of the MT wisdom literature towards the behavior of common rulers who ruled with arbitrary and unrestrained power and towards whom the common people must be exhorted to take great caution despite the enticements of power.
