Is longan orthodox fasting-compatible?

What to know about longan

Longan sits at the top of our FODMAP range: E for total FODMAPs, E for excess fructose, D for polyols and E for low-fermentation SIBO protocols. That combination is unusual, because most fruit is high on one axis and mild on the others, whereas longan is loaded on fructose and polyols at once. Practically, that means the failure mode is not one longan, it is the handful, and longan is a fruit almost nobody eats singly. Dried longan makes it worse in the obvious way: drying strips the water and concentrates the same sugars, so the dried fruit used in Chinese soups, teas and desserts carries a much larger FODMAP dose per gram than the fresh fruit does. Outside the gut it is quiet, with A grades for histamine, tyramine, gluten, glutamates, sulfites and oxalates and only mild B grades for salicylates, nickel and histamine liberation. It is worth knowing that longan is in the soapberry family alongside lychee and ackee, the family behind the unripe-fruit hypoglycin story, though the measured picture for longan is reassuring rather than alarming.