If red blood cells live longer, potentially due to increased membrane stability, Hemoglobin A1c might elevate and be a less accurate measure of average blood glucose over 90 days.

“and I wonder about we just don't have a good way to measure the life of a red blood cell in people and in speaking with my other colleagues I don't think it's ever been measured in ketogenic diet errs whether the red blood cell lives a longer amount of time the general life of red blood cell is ninety days and so it's assumed that a hemoglobin a1c gives us in a proxy for the average blood glucose over ninety days but if someone were if the red blood cells were living longer perhaps because of increased membrane stability as a hypothesis or other issues perhaps the a1c would elevate and would not be as accurate a measure”