Since October I've had to reduce my thiol and sulfite consumption after I had a reaction where I had to go to the ER.
At this point my husband and I have it where we've worked out how to replace onions with fennel, etc., but we've still not found a good substitute for garlic. Garlic powder isn't possible, it actually causes a more severe reaction than normal garlic. We looked at http://foodallergies.about.com/od/coo... but I can't use chives or horseradish. I can't use asafoetida because of a latex allergy.
This isn't an impossible diet (though a lot of people feel it would be), I just REALLY miss the flavor of garlic. So far the best I've gotten with a tomato sauce is to have either bacon or chicken broth that has had mushrooms steeping in it along with a LOT of oregano.
Note: what I have to eat is different than FODMAP, low carb or Paleo there there are superficial similarities because of meat allowances and dairy restrictions. I can't eat any brassica (broccoli, cabbage, kale, mustards) or amaranthaceae (spinach, amaranth, sugar beet, etc.). Beans are all forbidden, I can only have walnuts and almonds, most carbs are fine, that sort of stuff.