Glucose ketone index GKI calculator

Type a blood glucose and a blood ketone reading taken at the same moment. You get your glucose ketone index (GKI): glucose divided by ketones.

The index comes from Joshua Meidenbauer, Purna Mukherjee and Thomas Seyfried at Boston College, who published it in 2015. Where it comes from

mmol/L · Lo when the meter shows Lo
GKI
—

Type both readings.

glucose ÷ ketones, both in mmol/L

Track your GKI over time.Lomba saves each reading with its time, and shows how it moves beside your meals, fasts and sleep.

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The calculator gives the ratio. It does not say what the number means for you.Worked out on your device. Nothing you type is sent or saved.

01The formula

How GKI is calculated

GKI is blood glucose divided by blood ketones, both in mmol/L. A glucose reading in mg/dL is converted first.

Glucose5.0mmol/LFrom a finger-prick blood meter. 90 mg/dL ÷ 18.016 = 5.0 mmol/L.
Ketones2.5mmol/LBeta-hydroxybutyrate (BHB), the ketone a blood meter reads, in mmol/L.
GKI2.05.0 ÷ 2.5. A ratio, so it has no unit. A lower GKI means less glucose relative to ketones.
The same sum, four readings
Example values; the last two are from Duraj et al., 2024. A reading in mg/dL is divided by 18.016, as in the 2015 paper, and the GKI is rounded to one decimal. Picture redrawn from Figure 1 of Meidenbauer, Mukherjee and Seyfried (2015), CC BY 4.0. The original marks a zone the authors predict for brain cancer management; this drawing shows only the arithmetic.

02The source

Where the glucose ketone index comes from

“The ‘Glucose Ketone Index’ (GKI) was created to track the zone of metabolic management for brain tumor management.”

Joshua Meidenbauer, Purna Mukherjee and Thomas SeyfriedNutrition & Metabolism, 2015

The glucose ketone index was introduced in 2015 by Joshua Meidenbauer, Purna Mukherjee and Thomas Seyfried of the Biology Department at Boston College. With the paper they published a program, the Glucose Ketone Index Calculator, that tracks the ratio as a single value.

Nine years later, a research framework for glioblastoma by Tomás Duraj, Thomas Seyfried and their co-authors used the index throughout, and added how to measure it.

“The glucose-ketone index (GKI) is a standardized biomarker for assessing biological compliance, ideally via real-time monitoring.”

Tomás Duraj, Thomas Seyfried and co-authorsBMC Medicine, 2024

  • Meidenbauer JJ, Mukherjee P, Seyfried TN (2015)The glucose ketone index calculator: a simple tool to monitor therapeutic efficacy for metabolic management of brain cancer. Nutrition & Metabolism 12:12.doi:10.1186/s12986-015-0009-2
  • Duraj T, Kalamian M, Zuccoli G, et al. (2024)Clinical research framework proposal for ketogenic metabolic therapy in glioblastoma. BMC Medicine 22:578.doi:10.1186/s12916-024-03775-4

Both papers are open access under CC BY 4.0. Lomba is not affiliated with the authors, and they have not reviewed this page.

03The numbers

What the paper says about the numbers

The 2015 paper that defined GKI names only two figures, for the metabolic management of brain cancer. These are its words.

1 – 2
012612

  • “The zone of metabolic management is likely entered with GKI values between 1 and 2 for humans.”

  • “Optimal management is predicted for values approaching 1.0”

Joshua Meidenbauer, Purna Mukherjee and Thomas SeyfriedNutrition & Metabolism, 2015

The scale is the calculator’s, from 0 to 12.
  • What it looked at

    “data published on blood glucose and ketone levels in humans and mice with brain tumors”

    Joshua Meidenbauer, Purna Mukherjee and Thomas SeyfriedNutrition & Metabolism, 2015

  • What the authors say is still needed

    “Further studies will be needed to establish the validity of the predicted zone of management.”

    Joshua Meidenbauer, Purna Mukherjee and Thomas SeyfriedNutrition & Metabolism, 2015

  • The marks on the scaleThe scale’s marks at 1, 3, 6 and 9 follow a common convention for reading GKI, not a published or validated scale.

These values were proposed for brain cancer research. They are not validated targets for anyone else. Lomba sets no target and does not say what your number means; talk to your doctor about what you see here.

04Measuring

When to measure

  • Blood, not urine

    “Urinary ketones are not accurate for GKI calculation”

    Tomás Duraj, Thomas Seyfried and co-authorsBMC Medicine, 2024

  • The 2015 paper

    “blood glucose and ketone values should be measured 2–3 hours postprandial, twice a day if possible”

    Joshua Meidenbauer, Purna Mukherjee and Thomas SeyfriedNutrition & Metabolism, 2015

  • The 2024 paper, for people in a study

    “at least twice daily: after the overnight fast (morning), and 1–2 h prior to the last meal (evening)”

    Or once a day, “maintaining consistency across measurements”.

    Tomás Duraj, Thomas Seyfried and co-authorsBMC Medicine, 2024

The two papers give different times. What they share is a fixed routine, so one reading can be compared with the next.

From the blog: Glucose ketone index (GKI): what it is and how it is measured

Keep your readings in one place.

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