Here is my own experience:- after being raw-omnivore raw, palaeolithic for 5 years or so, I tried 3 100% raw animal food diet experiments(in my case, of course, minus raw dairy products, plus raw organ-meats and high-meats). I would never last more than 5-6 weeks. For the 1st 2 weeks, I would experience a heightened state of mental alertness, well, compared to before. But, within a week of the RZC experiment, I would soon end up with poor stamina with lifting weights/anaerobic activity. After c. 2 weeks on RZC, I would start getting severe mental fog, poor concentration, massive hunger-pangs which never disappeared no matter how much raw animal food I ate, my teeth, after being strong for years(post-RPD diet-start) started rapidly loosening, and so on and on. I would feel so ill, that, between weeks 3 and 6, I would quit and switch back to raw, omnivorous raw, palaeolithic diet. Given that I had the same sort of mysterious hunger-pangs while on raw vegan./fruitarian/sproutarian diets, I knew my body was missing raw plant foods, so this was a natural choice. However, switching back, as opposed to switching to RZC diets, caused a lot of problems with my digestion, presumably because my gut bacteria were not of the right variety. It took some weeks for the gut bacteria to change over until my digestion was OK.
My points:-
1)the Inuit have very large livers, designed to process/properly digest all the vast amount of animal protein in their diet. Most of the rest of Mankind do not. This explains why so many RVAFers do not do well, long-term, on RZC diets.
2) I may have made some mistakes when trying RZC. I took care to ensure that I ate a very high percentage of raw animal fat as my diet BUT I think I ate too much in general, thus ingesting too much excess protein.So, I would assume that any RZCer needs to eat much less food, overall. With all that raw animal fat in the diet, anyway, it is likely not necessary to eat so much.
3) After cutting out all raw dairy from my RVAF diet, early on in the diet, it took c.4 months for significant health-gains to occur. I did notice a tiny boost to my health on every single day of those 4 months, though, thank God, which helped me continue the diet.