Food is medicine. For example, an orange may help heal your liver. Even your appetite is probably enough (to find out), for many cases. Heal yourself, little-by-little. If not allergenic to you, and if not eaten excessively, that may rarely, if ever, hurt and the list of cautions have gathered since centuries, or millenia.
Except about the GMO (genetically-tinkered) varieties, if you call that food (or, drug), at all. For example, if FDA may approve any orange-look-alike as an orange, if-and-only-if it has sufficient vitamin-C, then it is an ignorance of the pages of remedies that other people had listed about an orange, or lemon, or apple, or onion, etc. The earth-people already knew the varieties of honey, or the mineral-water, varying from region-to-region. But a GMO, is a wild jump, unmatchable with the centuries-old accumulations of food-knowledge, as concerns the long-term effects of daily-consumption.
To think about a negative-cure, we may compare a drug, with a food case. We may think about a potato-meal. If it waits too long, it may turn (a little?) poisonous, and if consumed later, it may hurt your stomach. If your stomach was stuck, now you may feel relieved, to go to a WC. But if you were fine, it is what we simply call a diarrhea. To juggle such poisonous (negative) substances, may need extra knowledge.