Taking care of our health is a spiritual matter as it is a physical matter. The Bible gives us various reasons why we should take good care of our health, and we will do well to do them.
Here are some biblical reasons why we should take care of our bodies.
1. Christ bought your whole being with His blood
Christ shed His blood to purchase us from sin's captivity. We don't actually own ourselves – He owns us. And not just spiritually, but wholly.
"... You do not belong to yourself, for God bought you with a high price. So you must honour God with your body." (see 1 Corinthians 6:19-20)
Honouring God with our bodies, then, seems to be the most sensible response. We honour God with our bodies by taking care of it so that we could present it for His purpose. After all, our bodies belong to Him.
2. Our bodies are the temple of the Holy Spirit
We all have to understand that our bodies are the temple of God's very own Holy Spirit, the Spirit that He promised to give to us so that we could live following His ways.
No, you don't see 20-foot pillars in front of you, and neither will we see heavy curtains covering our bodies on a daily basis. What that means is that the Holy Spirit lives inside of you. Of course, you won't see Him because He's a Spirit, but you have to believe the fact and truth that if you are in Christ, God's Spirit automatically resides in you (see Ephesians 1:13).
"Don't you realise that your body is the temple of the Holy Spirit, who lives in you and was given to you by God? You do not belong to yourself..." (1 Corinthians 6:19)
My friends, we should take care of the Holy Spirit. God put Him in us to guarantee our salvation and make us follow God's precepts (see Ezekiel 36:27). How can we follow God if our bodies are incapable due to a sorry state of health?
3. We only have one body
Although we are promised to become recipients of a glorified body, we must realise that while we're here on earth, awaiting the return of our Saviour, we only have one body. And this one body is the only one that God gave us in order for us to live for Him and love Him.
Think about it. God's not the one who suffers when we're sick: We are. God's not the one who feels discomfort when we don't give ourselves rest. God is complete in Himself. However, we can't fully give our service and wholehearted devotion to God when our bodies are down. Indeed, "the Spirit is willing, but the flesh is weak." (see Matthew 26:41)