For anyone who isn’t familiar with the Glycemic Index (GI), it’s basically a measure of the ability of a food to raise your blood sugar. A food with a high GI causes a rapid increase in blood sugar (this is bad), while a food with a low GI increases blood sugar more gradually (this is desirable).
For years, it was assumed that the GI of a food is universal, however, research has shown that this is not the case. A study comparing the glycemic response elicited in Asians versus Caucasians, showed that the GI of a ready-to-eat breakfast cereal was 77 in Asians, while it was only 61 in Caucasians. So basically, the exact same food caused a larger spike in blood sugar in the Asians compared to the Caucasians. Researchers have speculated that this may arise from differences in starch digestion amongst ethnic groups. Nevertheless, regardless of the mechanism, it’s always interesting to see how the exact same food can affect different people in different ways.
I learned about this fact from: Venn BS, Williams SM, Mann JI. Comparison of postprandial glycaemia in Asians and Caucasians. Diabet Med 2010;27:1205-8.
That Nutrition Girl 
Interesting… does this depend on your diet as a fetus/child or is it entirely genetic?
Thanks for the question Andrew. Right now, the answer is unclear. They think there might be differences in the digestive enzymes in these different populations, but there’s no definite explanation. So while there isn’t any data yet to suggest that this is programmed from one’s fetal diet, the reality is, we can’t necessarily rule that out. It could be genetically passed down, but at the same time, we know that many of our genes are programmed during early life, and whether a particular gene is expressed can be greatly influenced by the foods one is exposed to during development, so it could definitely result from some sort of adaptation. Great question!