Glucose Ketone Index: The Ketone Levels Chart to Optimize Your Health

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Glucose Ketone Index: The Ketone Levels Chart to Optimize Your Health

Trying to calculate your ketone levels? Learn all about the Glucose Ketone Index (GKI) and how to use it for tracking ketosis.

A large part of success on the keto diet starts by tracking your ketone production levels. Using a ketone levels chart can help you determine if you’re in ketosis or if you might need to tweak your diet and macros.

If you’re just starting your high-fat, low-carb diet, you might have heard of different ways of testing your ketone levels, like blood ketone testing or urine testing strips.

However, you may not know that there’s a more accurate measurement called the glucose ketone index (GKI).

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This ketone levels chart is a simple calculation that allows you to find out how ketosis works best for you individually.

In this article, you’ll learn all about the GKI and how to easily track it for different aspects of your health and well-being.

What Are Ketones?

Ketone bodies are energy molecules your liver makes. Everyone has some level of ketones in the body, even without being in ketosis[*].

There are three types of ketones:

Ketone bodies are produced when you drastically cut carbs from your diet and your body stops getting sufficient levels of glucose. Glucose is your body’s primary fuel source when not in ketosis.

This lack of glucose makes your body turn to glucose stores (glycogen). When these become depleted, and your body doesn’t have enough insulin, it starts looking for alternative fuel sources.

That’s when your cells start burning fat, transforming fat stores into ketone bodies in your liver. This process is known as ketogenesis[*].

When you have enough ketones in your blood that your body can use for energy, you’re in nutritional ketosis. When you’re starting keto, it’s hard to know when you enter ketosis, so testing is essential in these first stages.

How to Test Your Ketone Levels

To find out what your ketone levels chart is, you must first test the level of your ketones.

There are three different ways to get your ketone reading: through urine, breath, or blood[*].

#1: Urine Ketone Testing

A ketone urine test is simple: You pee on a urine strip, wait for a few seconds, and see if any ketone bodies have been detected in your urine.

This is the most affordable option, but it also delivers the least reliable test results. Excess ketone bodies are excreted through your urine, and therefore the ketone strips don’t directly measure the amount of ketones in your bloodstream.

#2: Breath Ketone Tests

Ketone levels on your breath can be tested through a breath meter.

While this method is more accurate than urine testing, it’s still not optimal. Acetone, one of the three ketone bodies, is the one most commonly found in your breath. However, beta-hydroxybutyrate (BHB) is the ketone your body uses for energy and is the best one to measure how far you’re into ketosis.

#3: Blood Ketone Levels Testing Strips

Blood testing is the most expensive option, but it’s also the most accurate way to test your levels of ketones.

You prick your finger and use a blood ketone meter to measure the amount of BHB in your blood. It’s the same method to measure your blood sugar levels using a blood test kit.

BHB is the most abundant ketone in your body and the one used for energy in ketosis.

The Glucose Ketone Index (GKI) and How to Use It

You cannot classify a GKI number as “good” or “bad.” Instead, you need to understand how different numbers bring you closer to various health goals, such as weight loss, better overall health, or treatment of more serious conditions like type 2 diabetes, obesity, or cancer.

Below are some widely accepted glucose-ketone numbers for different conditions or treatments:

  • Anything above 9 means your body hasn’t transitioned into a fat-burning state.
  • A 6-9 GKI demonstrates a low level of ketosis. This is appropriate for those who want to lose weight or maintain optimal health.
  • A 3-6 GKI demonstrates moderate levels of ketosis. This is appropriate for addressing many common metabolic diseases, including insulin resistance, type 2 diabetes, or obesity.
  • A GKI less than 3 is a high level of ketosis. This is typically used for addressing epilepsy and cancers. Entering this high level of ketosis periodically each year can be beneficial for anyone hoping to use ketosis for disease prevention.

Ketone Levels Chart

To get the most benefits from ketosis, you want to get your GKI number as low as possible.

While you may use this ketone levels chart to tweak your macro guidelines, this measurement can also work in other circumstances, including:

  • Cancer treatment: Researchers first used GKI in the treatment of different cancers, especially brain cancer[*].
  • Diabetes treatment: The index has been used with metabolic therapy for both the prevention and treatment of type 2 diabetes and type 1 diabetes[*].
  • Fasting: The GKI is a tool to see how your body responds to fasting, and whether intermittent fasting helps you enter ketosis[*].
  • Athletic performance: Those looking to increase their athletic performance can use the index to see how their body responds to using ketones — rather than glucose — during competition[*].

How to Calculate Your GKI

To get your GKI reading, here’s what to do:

Measure your glucose and ketones levels at the same time. To do that, you’ll need:

  • A glucose meter and strips
  • A ketone meter and ketone test strips
  • A calculator for some simple math

First, measure your blood glucose levels as described on your blood glucose meter. Then, do the same for your ketone levels, following the directions on the test.

Once you have both numbers, take your glucose number and divide it by 18 (this is to convert the blood glucose reading from mg/dL to mmol/L.) If you’re not in the U.S. and the reading is already in mmol/L already, you don’t need to divide by 18.

Divide that number by your ketone level number. The simple formula is:

Glucose Level ÷ 18 ÷ Ketone Level = Glucose Ketone Index

Factors Affecting Your GKI

Many lifestyle and environmental factors can affect your GKI because both ketone and glucose levels change quickly in response to diet, exercise, stress, and environmental conditions. If you’re trying to maintain a low GKI number, keep these habits in mind:

  • Fasting: After eating, it can be pretty tough to stay in a very low glucose-ketone range because there’s a degree of glucose increase. Practicing intermittent fasting can be beneficial for decreasing blood glucose levels, keeping GKI low, and maintaining good health.
  • Nutrition: If your glucose levels are high, eating a ketogenic diet and watching out for hidden carbs can help improve your GKI ratio.
  • Stress: When you’re stressed, hormones like cortisol and epinephrine are released, which can cause blood sugar to rise. To keep that ratio low, focus on daily stress-reducing practices, and try to get plenty of rest[*].

Ketone Levels Chart and Your Health

The GKI is a useful tool for finding your ideal keto macros so you can achieve optimal health. While ketone testing can help you determine if you’re in ketosis or not, the GKI takes it one step further by factoring your glucose levels as well.

Testing your ketone levels can be helpful, especially for those who are just starting a ketogenic diet and for those who have adopted this lifestyle to manage their diabetes.

Diabetic ketoacidosis (DKA) can be a life-threatening condition that may occur when you have higher ketone levels in your bloodstream and may lead to a buildup. Therefore, testing while in ketosis is vital to ensure you’re doing it correctly and prevent any harmful side effects.

As always, if you have a health condition, check with your healthcare provider before you start a new diet.

Learning about your GKI number can be very helpful, and it’s entirely your choice on how to use it. Most people use it to dial in their nutrition, track their progress in ketosis, and recognize which foods help them reach their health goals.

By carefully monitoring your GKI, you can more easily enter (and stay in) ketosis and reap all its benefits.

To learn more about the importance of ketones, blood glucose, and ketosis, consider reading these articles:


26 thoughts on “Glucose Ketone Index: The Ketone Levels Chart to Optimize Your Health

  1. I have an iPhone app called KetoLogger that, once you enter your glucose and ketone #’s will calculate (and log) your GKI. I find the app handy to use.

    1. I’ve just started using this app too, what a great measuring tool! I’m running from 1.9 to 2.2 for three days.

  2. Has anyone consistently had great GKI numbers but no weight loss? I am at an average of .9-1.9 GKI for the past 30 days and the scale is not moving!

    1. I would pay attention to body compensation rather than scale numbers. You gain muscle while in ketosis so the scale may not always move but your measurements may be different.

  3. Has anyone had a problem with very high glucose readings even after a 12 hour fast? Mine is consistently 140-162. I have never had blood glucose readings that high even while eating a moderate carb, low fat, moderate protein diet. Ive been on this diet for a month now and can’t imagine my liver being able to consistently dump that much glucose out. I stay in the small ketone range as well.

    1. I am also diabetic and can tell you that I cannot fast successfully either. I have to keep an even supply of food in my system or my blood sugar either goes too high or too low, whichever it feels like doing. That’s why dieticians tell you to eat 6 small portions of food per day instead of 3 larger. To try and keep your blood sugars even.

      1. If I were you, I would take information from the keto diet. But also read Dr. Aitkins diet revolution book! He suggests not going 3-4 hours without eating! I successfully lost 103 pounds! Exercise and carb control is the real key!

    2. At one month of Keto, you are probably not “fat adapted” yet. You are in ketosis, but not fat adapted. From what I have read, if your body is not tolerating the fasting yet, you should try again in a few weeks. The average to become fat adapted varies, but generally it is 6-8 weeks.

  4. My goal is weight loss. But I am at 2.9 GKI which this article indicates is the level for disease prevention which is great. But is that level still good for weight loss? I am consistently losing but I am curious in the levels.

  5. Hi so I have been low carb for a month and a half. I just bought a ketone/blood sugar monitor and took my fasting measurements in the morning as 92BS and 1.2Ketone. After eating dinner I decided to retest and my BS126 and 2.6Ketone. Should I be concerned about this BS increase even though my GKI is 2.6? This was taken about 30minutes after eating too.

    1. That’s perfectly fine. (As long s you are not diabetic)

      A post meal glucose level can be anything from 110-140 approx an hour after eating. Your ketone level is excellent considering you have only been on a ‘low carb’ diet for a month (are you trying for full ketosis or just low carb?) For your info it has taken me 9 weeks to become fat adapted, which I am finding amazing by the way!

      My average ketone level is 3.8 and average GKI is 1.62. Stick with it, keep an eye on your macros, change accordingly and enjoy.

      My macros at present are Fat-75% (155g), protein-20% (100) and carbs-5% (15g).

  6. The idea that if you’ve got a GKI over 9 you’re not in fat burning mode is utterly ridiculous. Many times I have had a gki over 9 and ketones of 0.5mmol/l or over over. If you have ketones at or above even 0.3mmol/l you are obviously burning fat. GKI is not a pure measure of fat burning but the proportion of glucose to ketones. Fat burning is only related to ketones. There are many examples of fat adapted athletes who have ketone levels of just 0.3 to 0.4 mm per litre, one who was a boat rower crossing the channel on an 80% fat diet. Are you telling me they are not burning fat? Idiot. If a high GKI is due to a high blood sugar, this could well mean a lack of utilisation/uptake of glucose, for example after a postprandial measurement,
    or it could indicate insulin resistance. What it does not indicate is that there is no fat burning going on and if there were ketones in the blood then obviously there’s fat burning. You shouldn’t put information on like this because it will push people towards more and more extreme forms of dietary control at the expense of a broad range of nutrients, for example going below optimal protein or having such a small carb allowance that even green vegetables and nuts become an unaffordable luxury. See the leading researchers follow company who don’t ever mention the gki index and rather suggest that nutritional ketosis begins at 0.5 mmol/l and optimal ketosis between 1 and 3 mmol per litre. I get so angry with this pervasive, insidious miss information even on allegedly well-informed sites like this. Well it is not well informed. This website feignes to be expert in something it isn’t. Go to Virta health’s website into faultless, research backed information from the leading ketogenic diet researchers and authors that will not mislead.

    1. Hi Aaron, we see your frustration but would like to clarify a few things. It is important to note that the GKI isn’t the only factor in ketone levels. We actually agree that nutritional ketosis starts above 0.5 mmol/l. However, for your GKI to be above 9, your glucose levels would have to be so high that we would not consider your body to be in a fat burning state. Keep in mind that when you are testing ketones and glucose in the blood, you are getting a snapshot of what is currently available in the blood, or what your body has already done, not what it is currently doing.

      When your blood sugar rises, especially to the degree to get your GKI over 9, your body is going to shut down fat burning unless you are suffering from insulin resistance like you said or potentially prediabetes. That doesn’t mean that your body didn’t burn fat and produce ketones prior to that major elevation in blood glucose, which is why you may still see residual ketones in the blood when your blood glucose is that elevated or again it could be a sign of insulin resistance.

      In general, we know that in the healthy body, if enough blood glucose is available (which a GKI over 9 would be much more than enough) then the body is going to really slow or completely halt fat burning because the necessity is not there.

      We hope this clears up some confusion and if you have any other questions please do not hesitate to ask.

  7. I recently started keto 8 weeks ago. I lost 9 lbs in the first 2 weeks albeit water was a big part of that, for the next six weeks danced around that number.
    My fasting glucose rose in the mornings around week 7. I was shocked!
    I felt great my skin looked way better. All of my aches and pains went away. So i just kept on going.
    With the high fasting numbers my ketones dropped to .2 to .4 but i kept going.
    Week 9 my fg came down into the 70s to 82 range. Ketones up but not as high as during the first 6 weeks where i would reach 2 to 4 mmols. I am losing again.
    In week nine 5 lbs. My gki ratio is way better even at lower ketones. Why you ask? You can’t use you stored fat if insulin is produced constantly. I believe in the beginning I was making high ketones from the fat i was eating, which is great. I was full and this allowed me to implement IF (intermittent fasting).But for me it took some time to burn thru all of the liver stores and heal metabolic syndrome.

  8. Hi. I have been on KETO for 7 weeks. I have had positive results, lost inches, clear skin, energized, mood enhanced, and increased energy. However, weight loss is super slow. I know that I do have insulin resistance/PCOS. I recently started metering my GKI and the number is always high 8 or over. My KETO says between .4 and the highest is 1.1. Reading Aaron’s post and Clarisse’s response insulin resistance is the exception to all the KETO rules. What exactly does this mean? Is weight loss illusive? Should I follow a different KETO protocol? I would love to lose 20 pounds. Also, I upgraded to measuring blood instead of urine, because the urine strip never went up the trace or small color indicator. Any assistance would be appreciated.

    1. Becca, do not be discouraged! If you are insulin resistant, it may just take your body a little longer to adjust to this new diet. If you are keeping your carbs in check and adding exercise then you are doing the right things. Stick with it and the weight loss will come, it takes your body time to repair itself.

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