Physiological insulin resistance or adaptive glucose sparing may happen when someone goes on a keto, carnivore or very low carb diet (<30g/day) for a long period of time. Your body, and specifically your muscles, are forced to change their fuel source from glucose to ketones.
Your body has two fuel sources: glucose or ketones. Some body parts such as certain parts of the brain and red blood cells, do not have mitochondria and therefore cannot use ketones nor manufacture glucose. They can only burn glucose. When you are on a low carb diet, blood glucose is in very short supply, so these body parts get priority for your scarce glucose.
On a very low carb diet there is very little glucose going into the body from your diet. Your body can burn body and dietary fats called ketones. Your body may also use proteins and fats in the gluconeogenesis process to manufacture glucose, but this is also in short supply.
On a low carb diet your muscles may adapt to burn primarily ketones, which are plentiful. Over time your muscles depend less on glucose and therefore insulin. Body parts that can only burn glucose, such as certain parts of the brain and your red blood cells, are given priority for the scarce glucose that you have. This results in a higher glucose reading in, for example, your red blood cells. This will result in a higher than normal glucose reading from a blood glucose monitor.
Higher glucose readings due to these low carb adaptations are your body's way of saving scarce glucose for those body parts, such as the red blood cells, that cannot burn ketones.
To detect for physiological insulin resistance test fasting insulin and c-peptides. If insulin is low but your A1C is high then you have physiological insulin resistance.
I’m Doing Keto – And My Fasting Glucose is Terrible!!!: 05:11 physiological insulin resistance
Temporary glucose intolerance is likely a natural consequence of the body’s transition to fat adaptation. In making this shift, the body makes innumerable metabolic changes to prefer fat to carbohydrates. Then, when you eat a large dose of concentrated carbs, the body is simply unprepared. It hasn’t turned on the carb-burning apparatus in some time.
You travel along the path we call life, grow up and take for granted many things as gospel. Unfortunately there are some learnings related to diet that are so incorrect and can damage your health. It is like walking into a health trap set up for you by society at large. Family members and friends all believe in the same “truths” that you once believed. Here are some that I had to test and then was forced to change my stance on them.
