This reminds me of the story of Daniel in the Bible and how he and the other young men who lived off of "pulse" and refused to eat contaminated meat were seen to be stronger and in better shape than those who did after a period of time. 
There are SO MANY vitamins in vegetables and fruits! A balanced diet definitely seems crucial to good health. So many people don't realize that they are deficient in particular vitamins and minerals until they start taking them and realize the difference. 
Daniel 1:11-15:
And Daniel said to Malasar, whom the prince of the eunuchs had appointed over Daniel, Ananias, Misael, and Azarias: Try, I beseech thee, thy servants for ten days, and let pulse be given us to eat, and water to drink: And look upon our faces, and the faces of the children that eat of the king's meat: and as thou shalt see, deal with thy servants. And when he had heard these words, he tried them for ten days. And after ten days their faces appeared fairer and fatter than all the children that ate of the king's meat.
And, of course there are also the loaves and fishes (omnivores) of Matthew 14 and Luke 9.
"I am the bread of life" (John 6:48) is a passage laden with meaning and certainly mitigates against excluding vegetables (wheat) from our mortal and spiritual lives.