Mine crept up after decades of staying right where it should be. I read
books on the glycemic index and modified my eating habits (VERY slight
changes in eating patterns with almost no changes in content). It helped
little, so I took a couple of extra tests to identify the cause more
closely. The tests were grueling: give 'em a blood sample, stuff myself
with blueberry pancakes and syrup and orange juice, and give 'em another
blood sample. No anesthesia necessary, and problem solved: I simply
recover more quickly than the average bear from fasting, so my
14-hour-fasting blood glucose simply does its 15-hour thing in 10,
rather than 15, hours, throwing off the normal test. i.e.,. my
glycogenolysis was earlier than average, probably a healthy adaptation
to to my high aerobic exercise volume.

With any luck, somewhere in there is a tidbit of information of use to
you, such as the glycemic index, glycemic loading, and/or more detailed
analysis of your blood glucose patterns.

I.P.