I think there was an informed (with links to sources) comment in HN some days ago that stated that anything above 0.8g/kg drastically reduces lifespan. I wish I could find it
These studies are never in populations engaging in resistance training, the benefits of resistance training far outweigh any risks from protein consumption, which probably disappear once you increase strength and endurance training along with the proportion of whole foods that are plant based in the diet.
It would sure be nice if that paper explained what it meant by "high protein/high meat" without needing to delve into its 10 references. Ideally in the abstract.
Edit: found https://news.ycombinator.com/item?id=38727635