For we walk by faith, not by sight. (2Corinthians 5:7)
And since we have the same spirit of faith, according to what is written, “I believed and therefore I spoke,” we also believe and therefore speak, knowing that He who raised up the Lord Jesus will also raise us up with Jesus, and will present us with you. (2Corinthians 4:13-14)
Walking by faith and not by sight isn't just about the things that are known and received. It's about what we experience in our bodies. It's also freedom from sin we've already repented of and not being moved by what we see in our flesh.
Repentance is once. Standing by faith against lying symptoms in your behaviour is a process that's horrendously neglected in Christian instruction. As you wouldn't yield to a headache, cancer, or gunshot wound, why would you yield as though the Blood of Christ hadn't already cleansed you?
“Falling off of the wagon” is nothing more than a lying symptom of something the Word, the Blood, and the High Priestly ministry of Jesus has already dealt with. (Philippians 3:21)
So whether it's diet and fitness, less than the integrity of God, lust, muscle strain, worry, or lack, you are looking at things that have already been dealt with, when you first believed, by the grace of our Lord Jesus Christ. Your needs are met according to His riches in glory; you are seated with Him in the heavenlies, and you have been raptured out of the authority of darkness and raptured into the Kingdom of God's dear Son.
Your wholeness is a living reality and if you won't yield to circumstantial evidence, then the substance of what you've claimed with your faith will become the highest form of reality in your experience on this earth.