Temporary Carbohydrate Intolerance and Why the Keto Diet Can Cause It: other possible names include “adaptive insulin resistance, impaired glucose tolerance, physiological insulin resistance, peripheral 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.
…Many keto dieters will decide that the occasional blood sugar spike, in the context of an otherwise insulin- and glucose-lowering diet, isn’t worth worrying much about. Others may find inspiration to adhere even more rigidly to a low-carb approach, avoiding or entirely eliminating those glucose-spiking cheat meals. A third group may find the idea of temporary glucose intolerance uncomfortable, and seek to add more healthy carbohydrates to prevent temporary carbohydrate intolerance.
How to Balance Blood Sugar on a Low-Carb Diet
If you follow a strict low-carb regime, you may experience a condition called “physiologic insulin resistance,” also called adaptive glucose sparing.
People who are on ketogenic diets or other very low carbohydrate programs train their bodies to use fat, rather than sugar, as fuel. If you do this effectively, your muscles start to reject sugar when it is available. That means more sugar stays in your bloodstream, even when you consume very little of it.
High Blood Sugar you Don’t Need to Worry About (Keto/Carnivores Relax): Dr Ken Berry, 3:46 pathological vs physiological hyperglycemic episode
What’s the Difference Between Pathologic and Physiologic Insulin Resistance?: Dr. Paul Saladino
Is Keto Linked to Insulin Resistance? What the Research Says: 04:15 adaptive glucose sparing or physiologic insulin resistance
You’re Going to Become Insulin Resistant on a Keto Diet: Dr. Brett Osborn, they talk about insulin resistance on a long-term keto diet
Physiological Insulin Resistance & Adaptive Glucose Sparing
One of the clearest explanations of physiological insulin resistance I’ve seen comes from Paul Jaminet who says that physiological insulin resistance is a protective response of the body that ensures that the brain gets the benefit of a limited supply of glucose….
…I have seen some people run at very low carbohydrate levels and end up with progressively higher fasting blood sugars. Others see their fasting blood sugars continue to come down and ketones go up as they decrease the insulin load of their diet.
When on a lower carbohydrate diet you won’t have high levels of insulin floating around in your system and your body may choose to run blood glucose levels a little bit higher by secreting more glucose from the liver. This is not really a problem if you feel OK.
Many people find this to be a passing phase and after a time of keeping the insulin load of their diet low see their blood sugars come down.
As you keep the glucose load of your diet low you will ‘dry up the root’ and eventually after glucose stores in the liver are depleted, your fatty liver is resolved and your body fat levels are reduced you just won’t have as much glucose available for your liver to keep pumping into your bloodstream.
Physiological Insulin Resistance (2/2011) – Robb Wolf podcast, Harvard biochemist Mathieu Lalonde, 053-11:45
Does going low carb make you insulin resistant?: Compare and constrast pathological and physiological insulin resistance
High Glucose on Keto Diet – Adaptive Glucose Sparing
Blood Sugar Still High On The Keto Diet?: Curtis Alexander, Pharmacist, Here’s How I Fixed It. He mentions physiologic insulin resistance at 2:42
Can a Low Carb Diet Raise Blood Sugar?: Dr. Brian Mowll, 01:40 mentions physiological or transient insulin resistance
Help me explain to family how insulin resistance and glucose sparing isn’t diabetes
The Effect of Prior Carbohydrate Intake on the Oral Glucose Tolerance Test: study from 1960Sept-Oct, showing physiologic insulin resistance, loss of carbohydrate tolerance, then called “impaired glucose tolerance”
1. Eighteen healthy men and women, after showing normal glucose tolerance curves without any previous
dietary preparation, were placed on a 20-gm. carbohydrate, 1600-calorie daily diet for five days. Impaired carbohydrate tolerance on the 20-gm. carbohydrate diet was observed in both male and female participants, however, only two females showed curves diagnostic of diabetes by the criteria currently used in Public Health Service diabetes studies. Carbohydrate restriction in the females produced a greater loss of carbohydrate tolerance than it did in the males.
2. In an effort to restore normal glucose tolerance, the subjects were placed on a 150-gm. carbohydrate, 1640-calorie daily diet for four days. At the end of that period, normal carbohydrate tolerance (in terms of United States Public Health Service criteria) was fully restored and none of the subjects had curves indicative of diabetes or “possible” diabetes.
Is your fasting blood glucose higher on low carb or keto? Five things to know
Relax, it is normal — call it “adaptive glucose sparing”
“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 likely a good thing.
..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 a 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.
Higher Fasting Glucose on Ketogenic Diets: Reason to Worry?
Another reason for higher than expected fasting glucose is something called physiological insulin resistance. This is a phenomenon that occurs in people who’ve followed a very low carb or ketogenic diet for a significant length of time, and it’s somewhat related to the dawn phenomenon. In people who are keto-adapted or fat-adapted—that is, they’ve adhered to a very low carbohydrate intake for a long time—most of the body’s cells run happily on fatty acids and ketones, with a much lower requirement for glucose than in people on a higher carb diet. Since these cells are fueled effectively and efficiently by fats and ketones, they need only minimal glucose.
The majority of glucose is spared for tissues with an absolute requirement for it, such as the brain. With muscle tissue “refusing” the glucose in order to keep it available for the brain, the blood glucose rises, especially first thing in the morning. This is sometimes called “physiological insulin resistance” in order to differentiate it from pathological insulin resistance, but a better name for it is adaptive glucose sparing—an adaptation some people’s bodies make as a healthy, normal, and to-be-expected response to a very low carbohydrate intake.
Glucose & Keto: What You Need to Know & Monitor
Keto diets help to lower insulin levels. But, another common trend that we see is slightly higher glucose responses to a small amount of carbs. Individuals who follow a very low carb diet may have lower insulin sensitivity compared to someone who consumes more carbs. Keto diets can lead to a temporary physiological insulin resistance, in which the body overreacts when carbs are introduced.
Physiological insulin resistance is different from pathological insulin resistance. Pathological insulin resistance is a disease state, whereas physiological insulin resistance is a temporary adaptation.
Similar to the elevated fasting glucose levels with a keto diet, this does not appear to be a bad thing. What is happening is that the muscles, which typically prefer glucose, start to prefer fatty acids for fuel instead. Muscles are a huge sinkhole for glucose. So, when the muscles start to prefer fatty acids over glucose, consuming carbs tend to cause larger glucose elevations.
High fasting blood glucose on keto
Physiologic insulin resistance is sometimes called adaptive glucose sparing. When you are on a HIGH carbohydrate diet your muscles are the biggest users of glucose for energy. If you switch to a ketogenic lifestyle your muscles start to prefer fat for fuel. So the muscles start to actively resist insulin bringing sugar into the cells for energy. It is as if they are saying: ‘We do not need your sugar anymore, please take it elsewhere’. This then causes a slightly elevated, but generally stable, amount of glucose circulating in the blood.
…It also means, because of the body’s ability for gluconeogenesis, your body simply adapts. If you are fully keto adapted your liver will produce large amounts of ketones that can replace glucose as fuel for your brain, fatty acids then supply energy for muscles. And last but not least, glucose production from non-carbohydrate sources via gluconeogenesis supplies the carbons for the few cells that still depend on glycolysis (using sugar for energy).
Elevated fasting glucose while on low carb/ketogenic diet?
Low Carb Diets Causing Insulin Resistance? : Thomas DeLauer at 01:24 mentions “peripheral insulin resistance”
Insulin Resistance: You eat too many carbs and sugars. They are converted to glucose but your body cannot absorb so much. Your insulin levels rise to force glucose into your muscles. Over time it takes more insulin to do this. This is your typical T2 diabetes.
BREAKING THE BLOOD GLUCOSE MYTH WITH DR. ROBERT CYWES: Dr Ken Berry’s talk with Dr. Robert Cywes about diabetes, insulin, and low carb diets.
Insulin Suppression 18:56 : When you are on a low carb/keto/carnivore diet for a prolonged time, over a year, you eat very little carbs or sugars. Your body becomes fat adapted and thus makes and burns ketones. Your muscles burn ketones. Your insulin producing mechanism lags behind as it is no longer needed as much. When you do eat carbs or sugar you get a higher than normal glucose level spike and A1C because your insulin making mechanism is no longer required, so is slow to react.
In humans 20:18 the prime hormone for insulin release is an intestinal hormone GLP-1
Insulin is an important hormone and does many jobs. It may be better to eat between 50-75g of carbs/day 1:03:01, preferably early in the day, so that you maintain a little of the insulin response but still keep you in ketosis and enjoy the benefits of a low carb diet. A balance may be required to maintain this mechanism. Having this little bit of carbs also uses the GLP-1 agonist hormone, which makes you feel fuller, yet another benefit of having minimal carbs.
Another option 1:13:35 is to have a carb meal every 3d or 4th day. This is similar to giving yourself a GLP-1 bolus, which carries you for the next 3 days. 20:40 Small amount of sugar in your diet triggers 70% of GLP-1. GLP-1 increases insulin and lowers glucagon in the pancreas. This may be called carb cycling. Once you cure insulin resistance you can then transition into a maintenance phase where you need not be so strict.
In summary you want just enough carbs to keep insulin sensitive, the insulin mechanism working and responsive, but then quickly stops working so that most of the time you are using ketones as fuel and in fat burning mode.
While you can happily live with a low carb diet, there are tradeoffs. If and when you do eat some carbs, your body will not be well prepared and poised to deal with it, and you will see a glucose spike.
Insulin suppression: When you are so completely fat adapted that your insulin pathway becomes lazy. When you do eat carbs you get a huge insulin spike. The solution is to eat dairy, as dairy has both fat and glucose, or to eat a small amount of glucose/carbs. Insulin as a hormone is important and does much more than just fat storage.
2024 Mar 25 Ep:363 BRILLIANT EXPLANATION OF INSULIN SUPPRESSION: @BENBIKMAN, by Dr. Cywes, 17:12 carnivore diet is optimal but you must consume some milk. The milk triggers the insulin and GLP-1 pathway, 17:37 50-75g carbs, tops 100g
2025 Oct 05 MOST IMPORTANT DIET TALK YOU WILL EVER WATCH! pt 1Dr. Robert Cywes; explains insulin suppression; important charts at 40:56 and 57:27
2025 Oct 09 IS YOUR DIET MAKING YOU BETTER OR WORSE? pt 2 15:41 8-10% of diet should be carbs, 1:02:45 carbs are needed in the human diet to regulate hormonal homeostasis; “stay LCHF (low carb high fat), add 8-10% of slow carbs early in eating window or every 2-3 days”, avoid triggers to binge on carbs