This is very interesting - I wonder if it could also have interpretations with respect to discrepancy between ethnic groups with respect to insulin resistance and diabetes (which are both related to the speed that starch is digested).

It seems very probable that it does. I think the salient property is glycemic index.

Current estimate in Australia is that over 1 million people have Type 2 diabetes, of which about half don't know it. That's out of a population of only 21 million - those are pretty scary numbers.