The higher your HbA1c, the more you are also glycating the proteins in the lenses of your eyes, in kidney tissue, arteries, skin, etc.32 In effect, HbA1c provides an ongoing index of aging rate: The higher your HbA1c, the faster you are aging. So HbA1c is much more than just a feedback tool for blood glucose control in diabetics. It also reflects the rate at which you are glycating other proteins of the body, the rate at which you are aging. Stay at 5 percent or less, and you are aging at the normal rate; over 5 percent, and time for you is moving faster than it should, taking you closer to the great nursing home in the sky. So foods that increase blood glucose levels the most and are consumed more frequently are reflected by higher levels of HbA1c that in turn reflect a faster rate of organ damage and aging. So if you hate your boss at work and you'd like to hasten his approach to old age and infirmity, bake him a nice coffee cake.