In 1 Corinthians 6:12-20, the gist of the passage is talking about avoiding sexual sin. I find it interesting though that intermixed in this passage is a section about food and the body.
Sexual sin clearly affects the body, as well as the soul, deeply. And eating disorders—anorexia, bulimia, and even overeating—also affect the body deeply.
Overeating is a sin that often gets overlooked by Christians. But…I feel that God does not overlook it. I think He is grieved when I eat for emotional reasons instead of physical ones. He is also saddened when extra weight steals some of my energy. Energy that could be used for building up His kingdom and His people.
If I want to lose weight, this should be my greatest motivation.