Find the pattern. Not a guess.

No, and the reason matters. A wrong guess in one direction means eating something that hurts you. In the other it means removing food you never needed to remove — and that isn't neutral, because prolonged unnecessary avoidance can affect tolerance and occasionally creates the very problem it was meant to prevent. Allergy is diagnosed from a clinical history combined with targeted testing, and a questionnaire can't substitute for that. What this does is make the history excellent.

That's the most common reason people conclude there's no pattern, and there usually is one. Exercise, alcohol, anti-inflammatory painkillers, illness and hormonal cycles can all amplify a reaction — so the same exposure is tolerated on one day and not another. Once those are recorded alongside, an inconsistent picture frequently becomes a consistent one. Most diaries miss this entirely.

Home kits measuring food-specific antibodies of the intolerance type, hair analysis, and applied kinesiology or bioresonance. None has established validity for diagnosing allergy, allergy organisations advise against them, and they typically return long food lists that lead to years of unnecessary restriction. The validated route is skin prick testing or specific blood testing aimed at what your history already suggests, and supervised challenge where needed.

Not on its own. Skin and blood tests show sensitisation rather than allergy, and testing positive to something you eat regularly without any trouble is common. That's exactly why broad untargeted panels cause problems — they generate positives that lead people to cut out food unnecessarily. A result means something when it's checking what the history pointed at.

No, with one clear exception: anything that has caused a genuine reaction stays out. Otherwise keep eating normally, because a pattern can't be found in a diet that's already been changed. And never test a suspected food by simply trying it again — food challenges happen in a medical setting precisely because reactions can escalate unpredictably.