Here is another plausible explanation, may not be it but thought I would share. Found a real good article by a doctor that had the same experience as you. He calls it 'adaptive glucose sparing' ... I was unaware of this phenomenon ... the relevant portion of the article is pasted below ( link for article is https://www.dietdoctor.com/low-carb/fasting-blood-glucose-higher ):
“We definitely see that in people who are doing low carb long term, the majority will find that their fasting blood glucose becomes their highest value of the day,” says Dr. Sarah Hallberg. “They are not actually having issues with blood sugar. They are doing really well. But if you are looking at a log of 24 hours of blood glucose you will see a high first thing in the morning and then a steady decline throughout the day, with no big excursions [in glucose levels] even after meals.”
The scientific name is “physiologic insulin resistance” and it’s a good thing — unlike “pathologic insulin resistance.”
As regular visitors will know from
Dr. Jason Fung,
Dr. Ted Naiman, and
Ivor Cummins, the “pathologic” kind of
insulin resistance is caused by higher and higher levels of insulin — hyperinsulinemia — trying to force glucose into over-stuffed cells. That insulin resistance is a prominent feature of type 2 diabetes, polycystic ovarian syndrome (
PCOS) and other chronic conditions.
So let’s call physiologic insulin resistance instead “adaptive glucose sparing,” a name that has been proposed by many to reduce the confusion. Dr. Ted Naiman describes it as muscles that are in “glucose refusal mode.”
Prior to converting to the ketogenic diet, your muscles were the major sites to soak up and use glucose in the blood for energy. On the long-term keto diet, however, they now prefer fat as fuel. So the muscles are resisting the action of insulin to bring sugar into cells for energy, saying, in essence: “We don’t want or need your sugar anymore, so move it along.” Hence, the slightly elevated, but generally stable, glucose circulating in the blood.
Where is that glucose coming from when you consume no sugar and only leafy veggie carbs in your diet? Your liver, through gluconeogenesis — the creation of glucose from non-carbohydrate sources such as lactate, glycerol, and glucogenic amino acids from proteins. It is a natural protective process that got homo sapiens through hundreds of thousands of years of feasts and famines.
“There is no essential requirement for dietary carbohydrate because humans possess a robust capacity to adapt to low-carbohydrate availability,” says Dr. Jeff Volek. In the liver of a keto-adapted person, he notes: “ketone production increases dramatically to displace glucose as the brain’s primary energy source, while fatty acids supply the majority of energy for skeletal muscle. Glucose production from non-carbohydrate sources via gluconeogenesis supplies carbons for the few cells dependent on glycolysis [using sugar for energy.]”
Why are blood sugars highest in the morning? It’s
the dawn phenomenon, when cortisol, growth hormones, adrenaline and the enzyme glucagon pulse to the liver to get you up and moving for the day — spurring gluconeogenesis for the cells that need glucose.
“It’s your body making you breakfast,” notes one post that discusses the common phenomenon — except that when your muscles are fat-adapted, they don’t want it.
The
HbA1c test estimates the average glucose level in the blood over the previous three months by counting the number of glucose molecules stuck on red blood cells. On a low-carb diet the HbA1c will almost always be lower than the FBG suggests, showing that good glucose control, or type 2 diabetes, is not an issue for that individual.
pubmed.ncbi.nlm.nih.gov
