@thomasfuchs Personally I think there are several underlying causes, which is why diet and meds work differently in different people.
Antihistamines for mast cell activation did squat for me, but work wonders for others.
But in retrospect for me, every measure I took that helped control my insulin levels helped, while others failed. Most of my symptoms aligned with hyperglycemia, down to the incredible thirst, 130 oz a day. But without the high blood sugar or A1C.
Covid left my lungs scarred so I will never be what I was, but that is easier to deal with than that fatigue.
Edit: adding missing word