@leokitten did you ever figure out the tissue wasting?
I don't understand the question, the tissue wasting is definitely due to ME/CFS, it's one of my major symptoms. There's no other answer than this. I didn't take any antibiotics before getting ME and I know it's not antibiotic related.
My theory is that we know ME causes a major cellular metabolic block in PDH and aerobic glycolysis (multiple labs and studies have shown this) and our bodies struggle to compensate by initially consuming our tissue for energy, since it's not getting enough from food since PDH is blocked.