I'm an n of 1. That said, I tried various diet changes (i.e., dairy free, vegetarian) and life changes (e.g., exercise) and none had a substantive effect. When I removed gluten from my diet the effects were dramatic. In addition, I do have gluten on a rare occasion and my old symptoms return. Is this a placebo effect? Perhaps, but then why didn't any of my other significant experiments have any meaningful impact?

Note, I'm not suggesting that anyone with stomach issues has gluten intolerance. But if you do have persistent and long term stomach issues it is one of many conditions that should be seriously considered. Based on personal experience and research on the issue gluten intolerance is not a fad and shouldn't be dismissed as such.