Dr. Anthony Gustin is a board-certified sports chiropractor, functional medicine practitioner, entrepreneur, podcast host, and founder of Perfect Keto.
Doing this helps you know if you’re in ketosis and, if not, where you may need to tweak your diet and macros.
But did you know there’s an even more accurate measurement? The Glucose Ketone Index (GKI).
The GKI is a simple calculation that allows you to find out how ketosis works best for you individually.
Today we’ll be looking at how to easily track your Glucose Ketone Index for different aspects of health.
Ketones, or ketone bodies, are energy molecules made by your liver. Everyone has some level of ketones in their body even when they’re not in ketosis.
There are three types of ketones:
Here’s how ketone bodies are made: When you drastically cut your carbs, your body stops getting sufficient levels of glucose. Glucose is your body’s primary fuel source when not in keto.
This lack of glucose makes your body turn to glucose stores (glycogen), but when these get depleted, your body starts looking for alternative fuel sources. That’s when your cells start burning fat, transforming fat stores into ketone bodies in the 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 that’s why you need to test.
To know your GKI, you must first test your ketone levels.
There are three different ways to get your ketone reading: through urine, your breath or your blood.
#1: Urine Ketone Testing
A ketone urine test is simple: You pee on a urine strip, wait a bit and see if any ketone bodies have been detected in your urine.
This is the most affordable, but least reliable way to test your ketone levels. Excess ketone bodies are excreted through your urine, and therefore this test does not measure the amount of ketones currently in your blood.
#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 actually uses for energy and therefore the best ketone to measure how far you are into ketosis.
#3: Blood Ketone Testing
This the most expensive, but the most accurate way to test your ketone levels.
You simply prick your finger and use a blood ketone meter to measure the amount of BHB in your blood.
BHB is the most abundant ketone in your body and the one used for energy on ketosis.
Now that you know how to test your ketone levels, it’s time to better understand the GKI.
Developed by Dr. Thomas Seyfried, the GKI measures your glucose levels along with your ketone levels. This matters because even when you have high ketone levels, if your blood sugar levels are also high, you will not get the full benefits of the keto diet.
Researchers have used the index in multiple studies about the ketogenic diet and fasting to track changes and progress regarding weight loss, athletic performance, management of metabolic diseases like Type 2 diabetes and even cancer treatment.
Here’s how to use the GKI to your advantage:
#1: Track Your Ketone Levels and Blood Glucose Levels Simultaneously
The GKI lets you track both glucose and ketones at the same time, taking into account how they work together.
This is a better marker of your metabolic health than simply measuring ketone levels, because even if you’re deeply in ketosis, you could still have high blood glucose levels that throw things off and affect your health.
Knowing both measurements helps you make better health adjustments.
#2: Understand How Your GKI Correlates With Your Goals
You cannot classify a GKI number as “good” or “bad.” Rather, you need to understand how different numbers bring your 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 fairly widely accepted glucose-ketone numbers for different conditions or treatments:
- Anything above 9 means your body has not 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 less than 3 GKI 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.
To get the most benefits from ketosis, you want to get your GKI number as low as possible.
While you may use the GKI simply to tweak your macro guidelines, this measurement can als be used in a wide range circumstances, including:
- Cancer Treatment: Researchers first used the 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.
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.
So, essentially: (Glucose Level / 18) / Ketone Level = Glucose Ketone Index
Now you have your glucose ketone index!
Many lifestyle and environmental factors can affect your GKI because both ketone and glucose levels change easily 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 that GKI ratio.
- Stress: When we’re stressed, hormones like cortisol and epinephrine are released, causing blood sugar to rise. To keep that ratio low, focus on daily stress-reducing practices and try to get plenty of rest.
The GKI is a useful tool for finding your ideal keto macros so you can achieve optimal health. While ketone testing is useful for knowing if you’re in ketosis or not, the GKI takes it one step further by taking in account your glucose levels as well.
How should you use these numbers? That’s entirely up to you, but most people use it to dial in their nutrition, track their progress in ketosis and recognize which foods helps them reach their health goals.
By carefully monitoring your GKI, you can more easily enter (and stay in) ketosis and reap all the benefits.