I’m not sure humans would have maintained a purely carnivorous state for extended periods of time. Yes we have evolved to eat meat but we have also evolved to eat tubers. If we look at modern surviving tribes they dont eat meat every day in fact they often come back empty handed.
Vegetables are our evoltionary fall back food when we come back with no kill. It’s through the development of amylase enzyme which enables us to eat starches. If we weren’t supposed to do so why would we have evolved with this ability?
The question is as a species what do we do better eating… the answer is not black or white. Man would have eaten whatever he could to survive . We are hugely privileged to have the dilemma nowadys of to eat vegetables or not when In tthe third world there are still people starving… this is the reality. I’m really happy when people manage to become cured of overeating of the wrong type of foods… but to argue whether we can digest a salad or not is in my opinion possibly a step too far. Its fantastic that some are finding relief by eating this way. But to claim that this is the only way is misinformed
There is no research on this diet yet… simply because from the perspective of the world it’s extreme. The tribes which are simply meat were usually forced to do so through necessity. There were and still are many tribes who eat both plants and meat and do just fine…