Forgive me for intruding, but I have a similar problem that could be related that no Doctor has ever tried to address.
I have no diabetes, no chronic health problems, am now 65 at 6' and 170 Lbs., and went towards keto 15 years ago as a weight loss challenge with a buddy.
I initially lost 30 pounds by cutting the carbs, while he gained 20 pounds with medical help. Then I lost 30 more over a year.
At the time, I had bought a glucose meter for self-information. The only puzzling thing to me was a slowly rising fasting glucose that nobody could explain.
I recently broke out the meter, put a new battery in it, and am still exhibiting the same thing.
Woke up, drove 45 minutes to work, tested before putting anything down the hatch, and was 120 mg/dl.
Drank chia seed water and was 91 mm/dl an hour later.
Drank some EAA's and was 115 mg/dl two hours after that.
Got 4 eggs, one fork-full of hash browns steamed, and a piece of toast spread with 6 oz of cream cheese two hours after that and was at 124 mg/dl.
If it's like a 10 years ago, that will drop into the 70-80 mm/dl range for hours and then slowly head back up while fasting.
Back to considering why. My diet has changed over the years and lately I have not been getting enough fat at times, hence the chia and cream cheese.
When I get home from work it will be beef or salmon. Pain working 54 hours/wk. nightshift. But I think I'm fine, just curious as to the cause.
Weigh less and do more work than the twenty somethings, and exercise, and walk 10,000 to 20,000 steps a day.