ELI5: Physiologically, where does sugar come from?

I have been strict keto since Dec 7, 2021, so about 7 weeks. This is my second round on keto and I know the rules. I eat less than 20 carbs a day (total, not net), I monitor and weigh everything, I get the right amount of magnesium/potassium/sodium every day. I drink 100 or more ounces of water each day. I don’t eat keto “snacks” or fat bombs. I am 67F, 5’1, current weight 156 lbs. My macros are just over 1K calories per day, 16g carbs/80g fat/78g protein, and I rarely exceed them. I have lost a bit of weight from my starting weight of 163, but that seems to have stopped. Occasionally (about 2 times a week) I drink 1 or 2 cocktails in a night, usually Canadian whiskey, sometimes vodka or gin, on the rocks or with a shaker without sugar. I’m usually IF 18/6, occasionally OMAD. I usually get about 30 minutes of light exercise a day, usually biking and occasionally walking. My A1C on December 6th was 14.2, which shocked and horrified both my doctor and me. Doc wanted to go straight to insulin, but luckily she doesn’t mind me arguing with her, and I persuaded her to let me try keto + metformin for 3 months. He said that he doesn’t think the ketogenic diet and metformin adequately control my blood sugar, although she was encouraging about my willingness to try. Doc has me on 1000 mg of metformin 2 times a day, morning and night. He started checking blood glucose 3 to 5 times a day on December 7th. Blood glucose has dropped from an average of 350+ to an average of 200, but is no longer falling significantly. Typical range is 200-220 fasting overnight, 200-215 before and after meals. I sometimes (but rarely) get a reading of 170 or 180 at bedtime. I have read all the Taubes books and The Big Fat Surprise by Nina Teicholz. Can anyone tell me where that high blood glucose is coming from?

I have been strict keto since Dec 7, 2021, so about 7 weeks. This is my second round on keto and I know the rules. I eat less than 20 carbs a day (total, not net), I monitor and weigh everything, I get the right amount of magnesium/potassium/sodium every day. I drink 100 or more ounces of water each day. I don’t eat keto “snacks” or fat bombs. I am 67F, 5’1, current weight 156 lbs. My macros are just over 1K calories per day, 16g carbs/80g fat/78g protein, and I rarely exceed them. I have lost a bit of weight from my starting weight of 163, but that seems to have stopped. Occasionally (about 2 times a week) I drink 1 or 2 cocktails in a night, usually Canadian whiskey, sometimes vodka or gin, on the rocks or with a shaker without sugar. I’m usually IF 18/6, occasionally OMAD. I usually get about 30 minutes of light exercise a day, usually biking and occasionally walking. My A1C on December 6th was 14.2, which shocked and horrified both my doctor and me. Doc wanted to go straight to insulin, but luckily she doesn’t mind me arguing with her, and I persuaded her to let me try keto + metformin for 3 months. He said that he doesn’t think the ketogenic diet and metformin adequately control my blood sugar, although she was encouraging about my willingness to try. Doc has me on 1000 mg of metformin 2 times a day, morning and night. He started checking blood glucose 3 to 5 times a day on December 7th. Blood glucose has dropped from an average of 350+ to an average of 200, but is no longer falling significantly. Typical range is 200-220 fasting overnight, 200-215 before and after meals. I sometimes (but rarely) get a reading of 170 or 180 at bedtime. I have read all the Taubes books and The Big Fat Surprise by Nina Teicholz. Can anyone tell me where that high blood glucose is coming from?

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