Advanced Glycation End-products, or AGEs, the stuff of aging that mucks up brains, kidneys, and arteries, develop via two different routes: endogenous (from within the body) and exogenous (from outside the body).
Endogenous AGEs develop via glycation. Glycation of proteins in the body occurs when there are glucose excursions above normal. For instance, a blood glucose of 150 mg/dl after your bowl of stone-ground oatmeal causes glycation of proteins left and right, from the proteins in the lens of your eyes (cataracts), to the proteins in your kidneys (proteinuria and kidney dysfunction), to skin cells (wrinkles), to cartilage (brittle cartilage followed by arthritis), to LDL particles, especially small LDL particles (atherosclerosis).
At what blood sugar level does glycation occur? It occurs even at "normal" glucose levels below 100 mg/dl (with measurable long-term cardiovascular effects as low as 83 mg/dl). In other words, some level of glycation proceeds even at blood glucose levels regarded as normal.
There's nothing we can do about the low-level of glycation that occurs at low blood sugar levels of, say, 90 mg/dl or less. However, we can indeed do a lot to not allow glycation to proceed more rapidly, as it inevitably will at blood sugar levels higher than 90 mg/dl.
How do you keep blood sugars below 90 mg/dl to prevent excessive glycation? Avoid or minimize the foods that cause such rises in blood sugar: carbohydrates.
What food increases blood sugar higher than nearly all other known foods? Wheat.