Amongst emptying our lives of sin and then filling our lives with the Spirit and things of God, practical, regular, and reasonable physical exercise with some intentional good nutrition all play into the priesthood role of the believer's life for the excellent keeping of the Temple entrusted to them (their body)
Our bodies are the Temple of the Holy Spirit, and we must strive to be the best caretakers of the Temple God has placed us in charge of, just like God directed the Old Testament Priest to do in the materially-constructed Tabernacle and Temple before the coming of Christ.
After the first entrance and reascending of Jesus, He sent back the Holy Spirit. As the Spirit of God filled the Tabernacle and later Solomon's Temple in the Old Testament period, the Spirit of God fills us today that believe in the New Testament period. As the Priest of the Old Testament period carried out instruction from God for how to care for the Temple and then Go through the High Priest for connecting to God, today, believers have their instructions for caring for the Temple (our bodies) and for going through the new High Priest (Jesus Christ) to connect and remain in right standing with God.
"So Welcome and Fully Embrace Your Role in the Royal Priesthood!"
1 Peter 2:9 (NIV)
But you are a chosen people, a royal priesthood, a holy nation, God’s special possession, that you may declare the praises of him who called you out of darkness into his wonderful light.
1 Corinthians 6:19-20 (NIV)
19 Do you not know that your bodies are temples of the Holy Spirit, who is in you, whom you have received from God? You are not your own; 20 you were bought at a price. Therefore honor God with your bodies.