This gives me a little bit of pause as it’s not “of course”. I ride 8-12 hours per week and hardly ever resort to sugar. I usually take a banana with me, a rice cake bar sometimes, and only some extra sugar when I know it’s going to be a long/intense 4+ hour ride. I’ve only resorted to gels in fondos/events.
Anyway, it’s something to think about. Most rides don’t need to be “fueled” other than with healthy food.
There are conditions where a HgA1c test might not be accurate. I have a genetic anemia (thalassemia minor) that presents no problems for daily life and requires zero treatment but if I take a HgA1c test it will show as borderline or high. There are a bunch of things that can cause this borderline result so I’d research that and rule them all out before you decide you are borderline.