Scientists have long speculated that high diabetes rates among Native Americans may have roots in the evolutionary past. "Thrifty" genes that helped ancient hunter-gatherers store fat for survival during famine may contribute to diabetes in modern times of plenty.
The fact that everyone is now going in that direction doesn't seem to have struck these "scientists". For example, look at statistics from the United Kingdom National Health Service:
Prevalence and incidence of diabetes increased in the UK over 10 years - NeLM
Native Americans are just getting there a ittle quicker, that's all. This may well be partly a matter of genetics, but is also, one assumes, not unaffacted by the fact that the F.D.I.R (Food Distribution Program on Indian Reservations) is done in accordance with the U.S.D.A requirements ...
Always it's blame people's genes and don't even stop to consider what the current diet is like and just how far it has moved from what is normal for human beings given their evolutionary past.
Feces fossils yield new insights into ancient diets and 'thrifty genes'
Apparently, the "new insight" is that the diets of Native Americans in the past had a relatively low glycemic index.
Reinhard and Johnson conclude that this high-fiber, low-GI diet could have been the evolutionary pressure that fixed a thrifty genotype in place, leaving modern populations susceptible to disease when they moved to a modern diet of high fat, sugary foods that cause rapid spikes in blood glucose.
And of course, they're still not facing the fact that the "modern diet" is no more suitable for Immigrant Americans than for Native Americans.