Quick answer
Stolen bread tastes better going in. The verse does not deny the sweetness, which is why the second line lands.
Read both lines
Conceding the pleasure first is what makes this honest. A warning that began by claiming dishonest gain is unsatisfying would be answering a question nobody asked, and the book knows it, so it grants the sweetness and then moves the clock forward. The image in the second line is physical and specific, gravel in the mouth, which is not a punishment arriving from outside but the same meal continuing. That is the verse's actual claim about deceit: it does not get taken away, it turns. The same shape appears at 9:17, though there it is Folly herself saying stolen water is sweet, which is a character's line rather than the book's verdict. Both times the sweetness is granted, and both times it is early.
Related: Proverbs 9:17 · Proverbs 20:21 · Proverbs 13:11 · Proverbs 21:6
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.