What is the Glucose Ketone Index and Why Does It Matter? - Perfect Keto

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What is the Glucose Ketone Index and Why Does It Matter?


We’re all for using tools to improve our health and meet personal goals for our body. If you’ve never heard of or used the glucose ketone index (GKI), now’s the time to learn more about this useful tool. This article will fully explain what the glucose ketone index is and why it matters that we all use it.

What is the Glucose Ketone Index?

The glucose ketone index (GKI) is a single number that gives you a way to monitor the state of your metabolic health. Tracking your ketone levels lets you know how far you are into ketosis, and the GKI gives you a picture of the relationship between your ketone levels and your glucose levels. It’s simply an even more efficient way to see where you stand with your health.

Let’s take a second to talk about what metabolic health means, as this needs to be clarified for two reasons:

  • Many people who hear the term think of “metabolism,” which has been watered down a lot in recent times and is often misunderstood (such as the myth that intermittent fasting kills your metabolism, etc), and it’s not the same as an overall picture of metabolic health.
  • Metabolic health has been defined in many different ways by researchers depending on what’s being measured: triglycerides, blood pressure, cholesterol, etc. Perhaps most commonly, we see it used in tandem with research on type 2 diabetes patients. This can get confusing if we’re not sure what type of metabolic health someone is referencing.

Even experts haven’t completely agreed on a set definition of metabolic health, but the GKI index can help show the bigger picture. When we talk about metabolic health in the context of the GKI, we mean: the level of function in every cell of your body.

This is important because proper cell function means everything is working in harmony (also known as homeostasis).

Why the GKI Matters

The GKI has been used a lot recently in studies. From fasting to the ketogenic diet to finding the optimal metabolic state for treatment of the most prevalent conditions, the index may help us make some revolutionary discoveries, both personally and on a wider scale.

For example, the GKI has been used for tracking changes and progress regarding weight loss, improving athletic performance and workouts, and management or reversal metabolic diseases like type 2 diabetes and different types of cancers.

The glucose ketone index can help improve results for all of these things and more, including monitoring inflammation caused by high levels of glucose.

In his book Cancer as a Metabolic Disease, researcher Dr. Thomas Seyfried suggests trying to keep your GKI between 2 and 0.7, preferably shooting for 1. Seyfried uses the index in many of his studies around the ketogenic diet, fasting, and cancer.

In fact, the glucose ketone index can be especially significant when looking at ketosis and cancer. Cancer cells thrive on glucose, so it makes sense that we can help starve these cells when less glucose is present and more ketones are around.

Seyfried’s findings show that greatly reducing a person’s GKI reduces tumor weight and metabolism. Furthermore, a combination of lowering GKI and radiation treatment shows a reduction in tumor survival time by 5 times!

Essentially, if you have a history of any type of metabolic problems, whether it be cancer, diabetes or obesity, or you’re just looking to reduce your chances of these and keep your metabolic health in good condition, the glucose ketone index is a fantastic tool that can tell you a lot more than simply measuring one aspect of your health, such as cholesterol or triglycerides, or just your ketones—even though we recommend you always do that, too.

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Now that we’ve covered the basics of what the GKI does and why it’s important, let’s talk about how you can start measuring it for yourself today.

How to Measure Your Glucose Ketone Index

Measuring your GKI is really simple as long as you have a glucose meter and a ketone meter. Those who already measure their ketone levels will just need to take one extra step!

This is the formula for getting your glucose ketone index: (Your Glucose Level / 18) / Your Ketones Level = Your Glucose Ketone Index

This is all you have to do:

  1. Follow the methods for both the glucose meter and ketone meter, pricking your finger and using the strips for each to get your reading. Write each of those numbers down.
  2. Divide the glucose number by 18. (You must do this because glucose readings in the U.S. are measured in mg/dL, and dividing by 18 converts that number to mmol/L to match your ketones reading. If you’re not in the U.S. and your glucose numbers are already measured in mmol/L, skip this step.)
  3. Divide the number you get from #2 by your ketone reading number. This is your glucose ketone index.
  4. Use your GKI to determine where you stand. In general, anything below a 3 is a high level of ketosis (and low level of glucose), 3-6 means moderate ketosis, and 6-9 is a low level of ketosis. Remember, usually the lower the better.

Reaching a Low GKI

Reaching and maintaining a low glucose ketone index is certainly possible. Just give it some time and know that what works best for reaching the lowest numbers varies per person. Spend some time tweaking and testing to see what works and what doesn’t. And of course, eating a very-low-carb/high-fat ketogenic diet is the best starting place.

Take Home Message

Along with eating a healthy ketogenic diet and checking your ketone levels, measuring your GKI regularly can help you find your sweet spot and make the best choices for you and your metabolic health. There’s no better time than now to start!


5 thoughts on “What is the Glucose Ketone Index and Why Does It Matter?

  1. Love this. I find that JUST the Blood glucose reading OR the blood ketone reading may not be giving me a very good indication of where I actually am health wise.

    Going to start tracking the glucose ketone index for sure!

  2. I am struggling with getting my body to respond to the Keto diet. I have been on it for 4 months trying to help with my epilepsy. My BHB has been between .6-1.7 and glucose in morning around 98. I am eating 10 carbs a day per my prescribed dietician. I have been logging all food and I am on target. What am I doing wrong?

    1. You may not be eating enough fast and having too much protein. If there’s not enough fat with your protein you can spike your insulin.

  3. My ketones didn’t get very high, despite low carb diet, until I did a 36 hour fast. That seemed to jump start things nicely. And I cut out all alcohol.

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