Interesting you should mention this....I have Native American ancestors also, and my reading about them suggests that NA's ate a primarily protein diet with little sugar/carbs. When they were exposed to a European diet including sugar, carbs, and alcohol, they basically went crazy/became addicts because their bodies had never had to deal with this kind of food - so they dealt with it badly.

Perhaps it's not about latitude, but about the dietary habits (for literally thousands of years) of our ethnic ancestors coming down to us genetically vs. what food is socially acceptable/culturally common/available now (the last several hundred years.)

I'm not sure if I stated the above very well, but it explained a lot to ME about my own behavior/addictions.