That has not been my experience at all. Every time I try to add back things like fruit, honey, rice, potatoes, etc the negatives seem to outweigh any possible benefits (and I’m not really sure there is any benefit). I have no problem running 4+ miles with zero carbs. As long as I’m getting enough salt & fat life is generally really good.

The prominent carnivores who have concluded it’s unsustainable are people who heavily promoted liver consumption, & I did not do well when consuming liver. Results seemed consistent with vit-A toxicity. But without it I’m great (5years now), others like Kelly Hogan, Shawn Baker, Joe & Charlene Anderson have been doing the same for even longer with amazing results. Kelly is around 13 or 14 years, the Andersons are over 20