Well, lactose intolerance and gluten intolerance aren't dieting fads. I silently sneered at those labels, until I realized 6 years ago that I might have been lactose intolerant for the prior 10 years. (Now I know so.) And I felt the same way about gluten intolerance, until... 1 month ago. Now I realize that I have gluten intolerance. My intolerance for lactose is fairly strong, and for gluten, it's fairly weak, but now I know why I get stomach cramps and breakouts on my lower face. 75% of the world has at least some degree of lactose intolerance.