The article that's behind that one sentence is on an in vitro experiment (in a petri dish) where they found that short term exposure to glucose produced reversible effects on pancreatic cells, long term (23 weeks?) produced irreversible changes. But, it's an in vitro experiment, so its findings aren't as suggestive as the studies done in the body.
However, the first experiment listed on neuropathy found that OGTT were of more value than fasting blood glucose in predicting nerve damage.
OGTT may be more sensitive than FPG in the evaluation of patients with neuropathy because OGTT is a dynamic measure of peak glycemic control......Specifically, elevated peak serum glucose level may be a more potent pathogen for peripheral nerves than modestly elevated trough glucose levels.
Edit: Didi, in your original post I thought you were looking for information on blood sugars more than advice on how to change your diet. The studies that I've pointed to are not necessarily indications that you should switch your diet. Even people who are eventually successful at getting their sugars to behave completely normally can have a long adjustment period where post-prandial sugars are high.