The GKI combines your blood glucose and blood ketones into a single number. It is mainly used for therapeutic keto, and it needs a blood meter, not breath or urine strips.
| GKI | Meaning |
|---|---|
| Under 1 | Deepest ketosis, used in medical/therapeutic protocols under supervision. |
| 1 to 3 | High therapeutic ketosis. |
| 3 to 6 | Moderate ketosis, a common target for weight loss and metabolic health. |
| 6 to 9 | Low level ketosis. |
| Over 9 | Not meaningfully in ketosis. |
The GKI folds two readings into one because ketone level alone can mislead: high ketones with high glucose is a very different metabolic state from high ketones with low glucose. Dividing glucose by ketones captures both at once, which is why therapeutic protocols for certain neurological and metabolic conditions track it closely. For everyday weight loss and general health it is mostly a curiosity, and chasing a low number by under-eating is not the point. If you want to know whether you are in ketosis at all, the plainer options in measuring ketosis with blood, breath and urine are usually enough. Therapeutic keto should be done with medical guidance.
How do you calculate GKI?
Blood glucose in mmol/L divided by blood ketones in mmol/L. If glucose is in mg/dL, divide it by 18 first.
What is a good GKI?
Under 3 is high therapeutic ketosis; 3 to 6 is moderate and a common weight-loss range; over 9 is not meaningfully in ketosis.
Do I need a blood meter?
Yes. GKI needs a blood ketone reading, so breath and urine strips will not do.
GKI = blood glucose (mmol/L) ÷ blood ketones (mmol/L). Glucose in mg/dL is converted by dividing by 18. A lower GKI means a deeper state of ketosis. Most people doing keto for weight loss or general health do not need to chase a low GKI at all; the index matters most for therapeutic uses such as certain neurological or metabolic protocols, which should be done with medical guidance. This is general information, not medical advice.