Seems to me that I’ve read reports somewhere that the native American populations were a very healthy looking lot compared the Europeans that first came to the new world.
However, much of the Indian populations of north central and south America —were simply wiped out by new diseases brought over by the Europeans. further the die off so preceded the Europeans that with rare exceptions like in Mexico during the 1530 and 1560’s the Europeans had no knowledge of what happened. and how really big the Indian populations of the Americas were before they were wiped out by disease.
That this complete wipe out never happened in any parts of Africa or Asia. apparently because these populations already had been exposed to European diseases.
The Americas had at least four PreColumbian era population spikes, when the number of people approached the levels of circa 1900 AD; each was followed by a catastrophic falloff. This could have been due to climate, or could have been due to periods of transoceanic contact, or both. What it could *not* have been is the artificial and imaginary “over-specialization” argument that used to be dominant.
I think I read somewhere that the American indian dying off in large numbers is not the case and has been disproven