And the downside of *that* is that it can be self-fulfilling - if you cut *anything* out for a prolonged period, there's some chance of there being some kind of reaction when you reintroduce it. Usually temporary, but if you take that as confirmation of suspicions, then you'll end up cutting out foodstuffs or whole food groups for no damn reason.

Never do this sort of thing except under the supervision of someone who doesn't stand to gain financially from diagnosing an intolerance.