Understanding Green & King Index: Normal vs Optimal Ranges

?What is Green & King Index?

The Green & King Index (GKI) is a calculated ratio of blood glucose to blood ketones, expressed as glucose divided by 0.18 times the ketone concentration in mmol/L. It is used primarily to monitor metabolic state during ketogenic diets or therapeutic ketosis protocols. The GKI helps track the balance between carbohydrate and fat metabolism.

!Why It Matters

The GKI may help individuals optimise their metabolic state for weight management, mental clarity, or therapeutic purposes such as epilepsy management or cancer support protocols. A lower GKI can suggest a deeper state of ketosis and metabolic flexibility. Tracking this index can provide insight into how dietary and lifestyle choices affect metabolic switching, though it should be considered alongside other health markers and clinical context.

Reference Ranges

Lab normal ranges may vary between laboratories. Optimal and longevity targets are based on research literature and should be interpreted with your physician.

Symptoms of Imbalance

• Difficulty maintaining ketosis
• Fluctuating energy levels on low-carb diets
• Brain fog despite ketogenic adherence
• Inconsistent weight loss progress
• Keto flu-like symptoms during adaptation

How to Improve Your Levels

• 1Reduce carbohydrate intake to deepen ketosis and lower GKI
• 2Increase healthy fat consumption to support ketone production
• 3Incorporate intermittent fasting or time-restricted eating windows
• 4Monitor electrolyte balance (sodium, potassium, magnesium)
• 5Engage in regular physical activity to enhance fat oxidation
• 6Track food intake consistently to identify carbohydrate sources that affect GKI

When to Test

During initiation or maintenance of a ketogenic diet, when optimising therapeutic ketosis protocols, or periodically (weekly to monthly) to assess metabolic adaptation and consistency with dietary goals.

Related Biomarkers