Remember - medical literature is peer reviewed.
Not all reviewers are dispassionate - they makes decisions based upon their biases, not necessarily the science - note all the low carb researchers who complain about not getting published because their work does not fit the mainstream.

Better resources for indigenous diet would come from anthropologists who have no ax to grind on diet. Especially in the early days when anthropologists actually went out in the field and lived with their research subject for years before publishing