While we need to be diligent in honoring the Lord with our bodies, it is equally important to keep a proper perspective. There is a difference between being passionate in following God's ways and fretting or even making nutrition an idol. I love this poem:
Behold the fowls of the air: for they sow not, neither do they reap, nor gather into barns; yet your heavenly Father feedeth them. Are ye not much better than they?
But seek ye first the kingdom of God, and his righteousness; and all these things shall be added unto you.