Glucose Ketone Index (GKI) – What Ratio Do I need for Nutritional Ketosis Benefits?

Generally these blog posts are a result of scratching my own itch (answering my own question), and this post is no different.

At the time of writing this, I’m doing a 5-day fast, and wanted to understand the readings I’m getting for my blood glucose and blood ketone levels.

Initially I thought that blood ketones were all that mattered, and certainly a lot of people only talk about that reading. But looking at Dr Thomas Seyfried’s paper on treating brain cancer (glioblastomas).  It suggests that its important to take into account blood glucose also. In their study, they acheieved optimal results when their patients maintained what they called ‘nutritional ketosis’. And as part of the paper, they included a formula for what this means.

The chart below describes visually what they mean by nutritional ketosis, and how it affected the tumour growth. The red is an increase in ketones as a fictional patient goes deeper into ketosis. The black line represents blood glucose, that decreases to a plateau, as carbohydrate sources are removed from the diet, and glycogen stores decrease.

So that sweet spot they reach at the end is an optimum level of nutritional ketosis. Now… obviously in our case we are (hopefully) not trying to slow the growth of a glioblastoma. But by getting into ketosis we’re hoping to achieve a number of benefits including:

  • Reduced IGF-1
  • Immune system rejuvenation (perhaps mainly lymphocytes)
  • Increased cellular autophagy
  • Reduced inflammation (often measured by improved C-reactive protein levels)

The extent of these benefits will depend if you’re eating a keto diet, or doing a water fast/fast mimicking diet. But all 3 should improve the biomarkers such that you have a reduced risk of major diseases such as diabetes, cancer and cardiovascular disease.

And studies like this one indicate that the optimal benefits from ketosis lie in maintaining  a 1:1 or lower ratio of glucose to ketones.

So on to the crux of this post, how to calculate GKI. What you’re trying to do is compare apples with apples, you really really want both readings in mmol/L. In my case, having a meter sourced from the UK, that’s how they came, so I simply do:

Glucose Reading (mmol/L) ÷ Ketone Reading (mmol/L)

However, if you’re in the USA, your blood glucose reading will be in mg/dL. You’ll know, because the meter should say mg/dL. But to be sure, if you blood glucose is in the 100s as a score, rather than single digits, that’s likely mg/dL.

So you’ll want to convert that glucose reading into mmol/L by doing:

Your Glucose Reading (mg/dL) ÷ 18.02

This converts your reading from mg/dL into mmol/L, and then you can do the above calculation (glucose reading divided by ketone reading) to get your glucose ketone index score.

So that’s it really, pretty simple.

Links that may be of use:

1 – Thomas Seyfried et al’s paper on using the glucose ketone index to treat brain cancer:
The glucose ketone index calculator: a simple tool to monitor therapeutic efficacy for metabolic management of brain cancer

2 – An excel calculator for the GKI, developed by Dr Seyfried’s colleague Joshua Meidenbauer:
Glucose Ketone Index Calculator

What sticks out for me with all this stuff, is how amazingly valuable it can be in our treatment (and prevention of cancer), and yet in 2017 an incredibly small number of people (& physicians!) know and understand this work. For those with cancer, if its combined with other treatments, its even better. Its 5 years since Thomas Seyfried published his book ‘Cancer as a Metabolic Disease’. Time will tell how fast we are able to communicate this “meme” to a wider audience.