Indy51
Expert
As an aside, I think there is confusion between PIR and the general glucose intolerance that develops from being consistently low carb. Not a problem if you intend to stay low carb and don't have to take an OGTT. This is advice from Dr Michael Eades on how to prepare for an OGTT if you are following a low carb diet and the reasons why:
"Following a low-carb diet makes one a little glucose intolerant, which is the reason that the instructions for a glucose tolerance test always include the admonition to eat plenty of carbs in the week before the test. Why? Because all the macronutrients–glucose, fat and protein–are broken down by enzymes during the metabolic process. And all the enzymes necessary for the metabolism of the various macronutrients are made on demand but not immediately.
If you are on a high carbohydrate diet, then you will have plenty of enzymes on hand to deal with the carbohydrates you consume. If you switch to a low-carbohydrate diet, it takes a while to manufacture the enzymes in the quantities needed to deal with the extra fat and protein that your metabolic system hadn't been exposed to. This deficiency of protein/fat metabolizing enzymes is the reason people starting a low-carb diet become so easily fatigued–they've got plenty of enzymes on hand to break down carbs, they just don't have the carbs to metabolize. Once they produce the enzymes necessary to deal with the load of protein and fat, which takes a few days, they become low-carb adapted and no longer feel fatigued.
Once people become low-carb adapted then the same thing happens if they go face down in the donuts. They don't have the enzymes on board to deal with the sudden influx of glucose, and, as a consequence, their blood sugar spikes higher than it would on a person eating the same amount of carbohydrate who is already carb adapted."
"Following a low-carb diet makes one a little glucose intolerant, which is the reason that the instructions for a glucose tolerance test always include the admonition to eat plenty of carbs in the week before the test. Why? Because all the macronutrients–glucose, fat and protein–are broken down by enzymes during the metabolic process. And all the enzymes necessary for the metabolism of the various macronutrients are made on demand but not immediately.
If you are on a high carbohydrate diet, then you will have plenty of enzymes on hand to deal with the carbohydrates you consume. If you switch to a low-carbohydrate diet, it takes a while to manufacture the enzymes in the quantities needed to deal with the extra fat and protein that your metabolic system hadn't been exposed to. This deficiency of protein/fat metabolizing enzymes is the reason people starting a low-carb diet become so easily fatigued–they've got plenty of enzymes on hand to break down carbs, they just don't have the carbs to metabolize. Once they produce the enzymes necessary to deal with the load of protein and fat, which takes a few days, they become low-carb adapted and no longer feel fatigued.
Once people become low-carb adapted then the same thing happens if they go face down in the donuts. They don't have the enzymes on board to deal with the sudden influx of glucose, and, as a consequence, their blood sugar spikes higher than it would on a person eating the same amount of carbohydrate who is already carb adapted."