(Proverbs 18:20 KJV) A man's belly shall be satisfied with the fruit of his mouth; and with the increase of his lips shall he be filled.
I think there are a few assumptions here. My first assumption is that the person being referred to here has already made the commitments and repentance that lead to the washing of the blood and the fullness of the Spirit. This is a person who is not only talking the walk, but walking it also. What he says and how he says it are in accordance with the word. He is walking upright and talking straight. Proverbs would call that righteousness.
The second assumption is that “stomach” (990) is not talking about an organ in the body but the figurative center of our being. Poets would talk about their heart. Scientists might translate it as mind. It is the part of our being that takes it all in and either says, “All is in order” or “There is a dissonance here.”
So? Have you laid the groundwork for ultimate satisfaction or are you still going through the motions? It is a serious question with eternal consequences.