Betaine HCL has mostly eliminated my reactions, and I too was reacting to a lot. Fruits, veggies. Still react to a few, but very few. I am taking (8) 648mg at the beginning of every meal. Anything more than 8 and i get a headache.
Also, I am eating only veggies, fruit & meat. and taking antifungals. am following some of the Specific carbohydrate diet (google SCD diet). Am eating lots of salads and dandelion greens (prebiotic) and drinking kefir. Am hoping to heal what i'm quite sure is a leaky gut caused by candida and lousy flora from excessive Antibiotic use. Can't tell if it's working yet. But I suppose if it doesn't work, I'll just have to take the Betaine indefinitely. I tried giving up fruit, but am starving all the time, so I'm trying the candida diet and antifungals with fruit. most will say not to do this. but I didn't have the symptoms you or most describe other than getting sleepy after some meals. My main issue is breakouts from food.