I think we have to distinguish between allergy and food intolerance. I have had two ailments that have been escalating for two decades. One appears to be IBS and the other is a profound fatigue that at times leaves me unable to walk or stand.
I have since discovered that these disparate ailments have a common cause. It would appear to be wheat, and probably GMO wheat. The IBS disappeared with my discontinuing all wheat products, and the fatigue has not hit its frequent lows. I am going to have a blood test for food intolerances.