Carb Loaded Glucose & Insulin Challenge Test

By: Dr. Gary Huber

Posted 01/16/2023

Getting a fasting glucose test could miss a type 2 diabetes diagnosis. That's right, in 40% of cases a type 2 diabetic will go undiagnosed because the only lab that was drawn was a fasting glucose. 

In addition to getting a Hemogloin A1C tested, we recommend testing a 2 hour post prandial insulin level.  Checking your insulin after you eat 75 grams of carbohydrates will indicate how healthy your glucose metabolism is and will tell us if you are insulin resistant. The purpose of this test is to show your body a high sugar load and see how efficient it is at handling it. A poor response means your have increased risk for diabetes. Below is the dietary protocol two hours prior to the insulin test. You can order an insulin lab through here to order the lab)

Carbohydrate Insulin Challenge: 

Eat ONE of the following options 2 hours before having your blood drawn. 

  1. Carmel rice cakes x4 (“Quacker” brand has 44 grams of carb in 4 cakes) PLUS 2 tablespoons of traditional jam or jelly (“Smuckers” brand has 26 grams of carb per 2 TBSP). Total of 70 grams of high glycemic carbs.
  2. 1 large banana, 4 tbsp jelly/jam
  3. 2 cups diced mango (54 grams carbs), 1 large banana (25 grams grams)
  4. 1 & 1/3rd cup cooked white rice (60 grams of carb) PLUS 1 tablespoon jelly or jam (14 grams of carb) would total 74 grams of high glycemic carb.

How well does your body process glucose?  This is a CRITICAL question as it determines your risk for cancer, Alzheimers disease, heart disease, diabetes, weight gain, stroke and heart attacks. Everything related to aging and chronic disease starts with glucose regulation. If your cellular management of this is poor, then you are opening the door to pain and misery.

In your entire blood stream there is only 1 teaspoon of sugar. That's 4 grams of sugar in all of your combined blood. Yet a single can of Coke Cola or Pepsi contains 41 grams of sugar. That's TEN TIMES the total amount in your entire blood stream. A banana has 27 grams of carb that turns to sugar in minutes. Again, that one food item is a ton of sugar. If these foods are in your diet or if you eat a high carb “American” diet then this repeated insult will damage your ability to manage glucose which in turn damages your blood vessels. 

80% of the glucose that enters your body gets disposed of by the muscle. But if your muscle is not well conditioned or has been living in a high carb environment then the mechanism to dispose of glucose will be sluggish or in a poor functional state. A FASTING (no food eaten x12 hours) test of glucose will miss 40% of people who are glucose challenged, diabetic or insulin resistant. It is not a test of your body under demand, instead it is a test of your body at complete digestive rest.  I repeat – 40% of people with poor blood sugar control and trending towards diabetes will be MISSED when tested by FASTING glucose. That is a very poor result. We can’t trust that.

Why eat a carb load before a blood test? I want to see how well you as a machine are working. If you can’t process a 70 gram carb load within 2 hours then your machine is broken. Your muscles are out of shape, your insulin receptors have been damaged, your inflammation is high, your cancer risk and heart attack risk are rising. You want to know this. This is a critical piece of information that can’t be determined with a simple FASTING blood test.

“But I eat keto or low carb or Paleo and a 70 gram carb load will ruin this.”    No it won’t. If you are truly low carb or Keto then prove it. Pass this test. A healthy ketogenic diet will sharpen your ability to manage carbs and you will pass with flying colors. Yes, it will break your ketosis but only momentarily. If you are truly a ketogenic practitioner and healthy then you will be right back in ketosis by the end of the day or within 12 hours. If you aren’t then it shows that you have some work to do.

Don’t want to eat a 70 gram carb load and test glucose and insulin response?  Then don’t. But this means you are willing to put your head in the sand and pretend you are healthy rather than test your capacity, your true functional state, and prove to yourself that you are healthy. I won’t twist your arm but I want you to be fully informed on the risk you are taking. I have seen many lean, seemingly athletic people fail a glucose challenge test and they were able to use that information to make critical adjustments in their lifestyle to correct their insulin control and avoid chronic disease. You can to.

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