David J.A. Jenkins (MD, PhD, DSc) a University Professor in the department of Nutritional Sciences at the University of Toronto but was born in Britain.
Jenkins developed the glycemic index as a way of explaining the way in which carbohydrate effects blood sugar.
This all seems fairly simple, but as I've explained before the concept simply doesn't work. As Ray Peat points out,
"Orange juice and sucrose have a lower glycemic index than starch or whole wheat or white bread, but it is common for dietitians to argue against the use of orange juice, because its index is the same as that of Coca Cola. But, if the glycemic index is very important, to be rational they would have to argue that Coke or orange juice should be substituted for white bread".
Source; www.raypeat.com