Okay, so here’s what’s really important: it’s all about your food intolerance threshold!  

Chemicals can build up in your body slowly over time, then when your body reaches that individually set threshold you begin to experience symptoms.  Times of stress can affect your threshold level, including hormonal stress. You’ll often find that puberty (both sexes), perimenopause and menopause (females) are periods where you’ll react more noticeably to food because you have a lower threshold.

There’s good news, though!  

You can rebuild your tolerance to food chemicals by slowly adding food back into your diet.  

Start with just half a teaspoon every few days of a high-chemical food source.  For example, to test for salicylate sensitivity, add a half a teaspoon of a high salicylate food to your diet and see if you react poorly.  If you react, then cut it back again.  If not, gradually build your tolerance by adding more of that food every few days.  Each time you react, cut it back again.  Make sure the food you choose is only high in one particular chemical, or you will confound your results. More info in the elimination diet handbook listed below.

Food intolerance often runs in families, but affects family members in differing ways.  If, for example, one person reacts to salicylates with hyperactivity, their offspring may react by becoming irritable or developing a migraine.