Celiac disease (CD) was initially described in the 1st century by a Greek physician, but it didn’t become clear that CD was caused by an autoimmune reaction to gluten until 1950. Since then, the mainstream view of gluten intolerance has been black & white: either you have celiac disease or you’re tolerant. The truth is, like most things, there are many shades of gray. It turns out most recent research shows it’s possible to have gluten intolerance without having CD. This is known as non-celiac gluten sensitivity (NCGS), and gluten intolerance is more a spectrum of conditions than a single condition.