Iron, I just tell people that the grains make me feel rotten when I eat them--which is true. If they question me further and seem to understand celiac disease (which I don't have), I just say that I'm "sensitive" to grains. Then if they try to question me further, I just do the wide-eyed shocked innocent "Oh, I really don't think you want to hear about my intestinal problems (make yucky face here)..." and that usually shuts them up!
If they seem more interested than condemning, I start slowly with the indoctrination!
You make your choices, and you live with them. In the end, you are those choices.
"Strength is the mental and physical fortitude to endure, resilience to bounce back, and force to create change, allowing you to thrive in any circumstance and through any adversity." TrPAssassin