The fructose does not raise the blood sugar level because it goes to the liver to be processed, mostly into fat. Excess consumption of fructose will cause the same condition as excess alcohol (alcohol is also exclusively processes by the liver), fatty liver.

Blood glucose has been the focus on managing diabetes and the glycemic index is part of that focus. But the root cause of the metabolic problem is insulin resistance and fructose is a big contributor to making the liver insulin resistant. Insulin resistance can vary in its severity in different parts of the body. Most recently it is believed insulin resistance in the brain is related to Alzheimer's and other forms of dementia. Some now refer to it as type III diabetes.

Lot of new research on the subject in the last ten to twenty years. A lot of the medical community is that far behind on nutrition information. Some of the pathways have only been discovered recently. Textbooks written earlier do not reflect the new information.

John