It is interesting that they noticed less insulin receptors in the brain of those with Alzheimer's after an autopsy. I'm wondering if there is an easy way to track insulin receptors while someone is alive and be able to do a long term study. I think it would be difficult because it is dealing with the brain though and couldn't be an easy blood test to see.
Could sugar play a part in less insulin receptors? Yes, no maybe? They do show a link between uncontrolled blood sugar level (aka diabetes) and alzheimer's but there could be other things as well. I think overall diabetes causes havoc on the body and is something to be avoided. I had 2 great grandparents and 1 grandparent who had diabetes. They all lived to be in their 90s but their last few years were rough, my great grandmother went blind my great grandfather had his leg amputated and my grandfather, well he was fairly healthy until the last couple years of his life but it seems diabetes weighed him down.
You can't out-exercise poor eating habits.