IT'S NOT A SIN TO BE FAT!
That being said, we are called to take proper care of our bodies. Or do you not know that your body is a temple of the Holy Spirit within you, whom you have from God? You are not your own, for you were bought with a price. So glorify God in your body.*
One way of doing this is to have a healthy diet and to exercise properly. It's not about being dead sexy: it's about living long so that you can tell as many people about Christ as possible. People who diet and exercise live much longer, healthier lives than people who...don't. So if your future wife thinks the major food groups are deep-fried, chocolate-covered, cream-filled, extra cheese, and double scoop, then friendzone her! She can't be your help meet if she is constantly in the hospital having self-inflicted quadruple bypass surgeries. Also, don't be a hypocrite: make sure that you are laying off the sweet stuff, too! For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord!**
*1 Corinthians 6:19-20 (ESV)
**Romans 6:23 (ESV)
