The book repeats this saying word for word at 26:22.
Quick answer
Gossip is delicious, and that is exactly the problem: the talebearer's words go down like delicacies and lodge in the inmost body. The proverb explains why gossip spreads. It tastes good.
Read both lines
The first line refuses to pretend gossip is unpleasant. The talebearer's words, the footnote allows "gossip or slanderer," are tasty trifles, and one Jewish tradition preserved in the NKJV margin reads "wounds," perhaps the truest double meaning ever to sit in a footnote: the delicacy and the wound are the same bite. The second line follows the morsel down, literally into "the rooms of the belly": the report you swallowed does not pass through, it moves in, seasoning how you see the person it concerned. The sages repeated the saying verbatim at 26:22 because the appetite never goes out of season, and the warning aims at the consumer, not just the cook: gossip exists because we eat it.
Related: Proverbs 26:20–22 · Proverbs 16:28 · Proverbs 17:9
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.