Positives

• A 26-year-old with very severe ME/CFS after two COVID infections went carnivore in January 2023 for severe MCAS and then moved to a warmer sea climate, recovering from bedbound to 80% of her former self within a year — she could work, walk, and hike again though intense sports remained off-limits Reddit.
  
  
• An 8-month long-hauler tried eating carnivore for one day and reported feeling 99% normal with inflammation and immune response “totally gone” and significantly more energy, though the poster acknowledged it could be a fluke Reddit.
  
  

Negatives

• High saturated-fat and zero-fiber intake on carnivore can raise LDL, alter lipid particle size, and worsen postviral insulin resistance, especially in patients with ApoE4 — the diet also strips polyphenols and butyrate substrates that support gut and immune balance Health Rising.
• Constipation is a common reported side effect on carnivore, and removing fermentable fiber undermines the gut microbiome — patients describe short-term symptom relief that fades or reverses with longer adherence Longcoviddietitian.

Hurdles & Side Effects

• One long-hauler with POTS noted that entering ketosis on the carnivore diet actually worsened their heart rate by 10–15 beats, suggesting people with POTS should monitor carefully during the transition period Reddit.
  
  
• Community discussion suggested that the carnivore diet’s benefits may come primarily from being a low-histamine elimination diet rather than from meat itself, since most fresh meats are naturally low in histamine — this could explain why some patients with MCAS-like symptoms see improvements Reddit.