There are millions of people who would disagree.

It seems to me that anyone whose ancestors were in Europe during the last ice age is well adapted to an entirely carnivorous diet because we've only had 10k years to have winter access to plant based food, which isn't enough time to adapt to a plant based diet, let alone to lose the diet that we conquered the world with

Vegans do badly without supplements, most carnivore diet followers don't take any supplements other than salt, and many don't take salt.

How does your model of metabolism deal with living on a glacier?