I am just guessing here, not having studied the issue in depth, but someone whose ancestors lived in South East Asia (or East Asia), where rice has provided the

I am just guessing here, not having studied the issue in depth, but someone whose ancestors lived in South East Asia (or East Asia), where rice has provided the majority of the calories for thousands of years, can probably remain healthy on a diet high in refined carbohydrates, a diet that is clearly unhealthy for me, whose ancestors come from Northern Europe where keeping cows and later pigs was a large part of the agricultural economy for the last 6,000 years or so (and before then there was a large supply of large animals available for hunting -- large animals that specialize in eating grass and therefore are not loaded with parasites the way that animals that sometimes eat meat are). I do much better when most of my calories come from fat and protein. But I do not partake in the ketosis fad: I eat a small amount of carbs with almost every meal, and if I don't, I get heart palpitations. (And I've seen studies showing the ketosis is a strain on the heart.)