'Lean' in the Bible

Now in that day the remnant of Israel, and those of the house of Jacob who have escaped, will never again rely on the one who struck them, but will truly rely on the Lord, the Holy One of Israel.

“Now in that day the [former] glory of Jacob [Israel—his might, his population, his prosperity] will fade,And the fatness of his flesh will become lean.

“Trust [confidently] in the Lord forever [He is your fortress, your shield, your banner],For the Lord God is an everlasting Rock [the Rock of Ages].

Who is among you who fears the Lord,Who obeys the voice of His Servant,Yet who walks in darkness and has no light?Let him trust and be confident in the name of the Lord and let him rely on his God.