In my opinion, the most remarkable experiment nature has yet done on our species with LC diets is the inuit one.The Inuit thrived over many generations in (as far as we know) good health and shape on such a diet in spite of a particularly hostile environment for a species of tropical origin.
Yet it is clear that their diet
-was not ZC. They gathered apparently all the food of plant origin, they could, such as berries or seaweeds.
-was not based solely on meat and fat from a single or even a few terrestrial mammals.
-included a large amount of seafood and organs and the content of organs. The fat in particular was largely blubber.
With respect to modern ZC diets based on pemmican the apparently proven and safe Inuit diet was actually much more varied and these differences or "details" might well be quite important.
The Inuit I and Stefansson knew live in the Western Canadian Arctic, where there are few if any berries, and no seaweeds eaten AFAIK.
Their diet was of both terrestrial and marine mammals, mostly marine; they caught fish to feed their dogs and probably only ate fish when they had nothing else to eat.
They had rendered fat all winter for light and possibly food, and there was nothing to stop them from eating it, since TD was not there.
The only reference to organs I remember was Stefansson's remark that they ate the flesh of fish, and gave the rest to the dogs.
My impression was that paleoman and Arctic peoples may have used plants/veggies for medicinal purposes, as cats and other obligate carnivores do, but not otherwise as they are not food and in other than tiny amounts always do harm.
Re kidney stones/calcification - IIRC calcium is always deposited in the bones and teeth unless something makes calcium metabolism go wrong, such as pasteurized/homogenized dairy. I vaguely remember having read of something else that could cause calcium deposits in flesh, but can't remember what it is.
Having been deposited in flesh/organs, it seems that it persists for a long time unless something unusual is done to remove it - Hulda Clark's liver or kidney flush is one, IIRC there was a special kind of tea used in British medicine which also dissolved stones.
There are no reports of traditional pemmican-eaters (sub-Arctic peoples) ever having kidney stones.
