Dark chocolate

cocoa and dark chocolate are very high in oxalates, and the more cocoa it contains, the more oxalate. Milk chocolate has less oxalate but still adds up if you eat a lot.

dark chocolate is low FODMAP in a small amount, but milk and white chocolate add lactose and more sugar, raising FODMAP. Any large serving becomes high FODMAP.

cocoa and chocolate are histamine liberators and also block DAO, the enzyme that clears histamine, a double problem for sensitive people. The darker and more cocoa-rich, the stronger the effect on histamine.

This is a weak entry and worth saying so: chocolate, cocoa, nuts, citrus and coffee appear on legacy MAOI lists, but modern reviews found their tyramine too low to matter at normal portions — chocolate's effect, if any, is attributed to phenylethylamine rather than tyramine. They were dropped from the strict list decades ago. Test rather than avoid on principle. Sources: Gardner et al., J Clin Psychiatry 1996 (review that narrowed the MAOI diet); McCabe-Sellers et al., J Food Compos Anal 2006.

not a dairy food, but milk powder or whey is a routine ingredient here, so the lactose depends entirely on the brand. Usually a small dose; check the label, where milk must be declared as an allergen.

this processed food may contain gluten from fillers, malt, wheat starch or shared production lines, even though it isn't a wheat product itself. Check for a gluten-free label if you are sensitive.