a person should take care of her body and keep it healthy
—My body is a temple. That’s why I eat only natural foods.

While telling Christians to avoid sexual sin, Paul writes, 

Flee sexual immorality! “Every sin a person commits is outside of the body”—but the immoral person sins against his own body. Or do you not know that your body is the temple of the Holy Spirit who is in you, whom you have from God, and you are not your own? For you were bought at a price. Therefore glorify God with your body. (1 Corinthians 6:18-20) 

In Jesus’ day, the Jews were still worshipping God in the temple in Jerusalem, but in AD 70, the Romans destroyed the temple and it has never been rebuilt. Here, Paul tells the Christians that their bodies are temples because God’s Spirit lives inside them.