Optimal Ketosis: How I Tracked My Blood Ketone and Glucose on a 48 hours self experiment


This is my most interesting article ever. In my previous posts, I talked about my journey to ketogenic diet and how I  kept track of my blood ketones levels to maximize the fat burning.

My goal was two fold 1. To see if the high fat low carb diet has any impact on my endurance performance and 2. Weight loss that will eventually make me faster. Here is what happened to me when I switched to this diet last year.

Lets do a brief recap of all terms related with keto diet, so that  we are on the same page. Later in this post, I will walk you through some exciting ketone and glucose data.

Ketones and how to quantify them

When your are in the state of optimal ketosis, you will burn good amount of body fat. A  few questions to answer before we go further

How do you know if you are in ketosis or not?

Well, measure the amount ketones in your blood.

How to measure the ketones in blood?

Use a blood ketone meter. I have mentioned best ways to measure ketosis in the last part of this post.

Some ketone measuring device such as Keto Mojo combine the ketone and  glucose. You just need to use different stripes for both biomarkers. The great part is that glucose stripes will also provide you the value of HCT and hemoglobin. So, now you have 4 things to measure in your blood. More data, more fun.

What is HCT?

HCT stands for Hematocrit. This the total % of red blood cells in your blood. More is certainly better as long as it is not way out of normal range. People living on high altitude have more HCT than the people staying at lower altitude.

I did some reading on HCT and hemoglobin and found that the normal range for HCT for men is 42%-52% and 37%-48% for women. The level of hemoglobin is between 13.5-17.5 g/dl  for men and 12-15.5 g/dl for women. I still need to ask my coach Anthony Kunkel about his HCT level. It must be more than mine for sure because he lives in Durango, Colorado which is a high altitude place.

Now, we know how to measure ketones and other blood markers. Let us talk briefly about how one can get in the state of ketosis.

How to get into ketosis

Getting your body into ketosis can often times be overwhelming. Kick starting fat burning process is a huge challenge for beginners. However, it can be done either by intermittent fasting (fasting 16-20 hours a day) or complete water fasting for couple of days. Learn more about  how to induce ketosis quickly

We now have a solid background of ketones and how we can turn our body into a fat burning machine. So, I decided to check my blood glucose and ketone levels during the period of 48 hours. In that period of time, I did coffee fasting and coffee+egg fasting. Here are the experiments that I performed on myself.

Self Experiment 

Let’s start with the blood Ketone levels and how their value can be affected by exercise and fasting.

In this article, I will lay out two different experiments.

  1. First experiment: 48 hours (coffee only) fasting- I had only black coffee in 48 hours. The amount of coffee in this time was around 8 cups. My fast started at 7 pm on April 23 and end at 7 pm on April 24, 2019.
  2. The second experiment: I did egg fasting for 48 hours. Again? I included coffee during my fast. Total 11 hard boiled eggs and 8 cups of coffee in 2 days.

I also ran 4 times during both of the fasting sessions. Running pace was however slightly different in both of them. 

Let’s now dive deeper into what happens to blood ketone levels. I also measured my glucose, HCT and hemoglobin along with ketones.

The test stripes were provided by Keto Mojo. They had some amazing functionality of measuring HCT and hemoglobin along with glucose.

Therefore, we have 4 blood markers that will vary during the experiment. We will also see how exercise have impact on them and what their levels reveal.

Coffee fasting for 48 hours -I ran 4 times as shown in the pictures
Experiment with egg fasting
Egg fasting for 48 hours-I ran 4 times as shown in the picture

Blood Ketone Data:

Since I drive to work, I decided to include coffee in my 48 hours fast. I did not want to drive sleepy.

Experiment 1:

Day 1:

On April 23, I finished my dinner at around 7 pm and decided not to eat anything till 7 pm on April 25. 

About 11 hours without food (mainly the night sleep), my keto meter readings shows that I have no ketones flowing in my blood. 

My ketone level at 6:30 am was 0.0 mmol. WHY?

Part of the reason might be my carb intake in the night before. I did not pay too much attention to my food previous night and loaded myself with tons of carbs. That is why my body was mostly relying on glucose for energy source.

Graph1: Variation of Blood ketones in coffee and egg fast

It might also be due to a dawn phenomenon and/or Somogyi effect. I learned about this after observing that my ketone level has always very low in mornings.

Human body go through a cycle of glucose. It will be more at certain time of the day. During dawn or early morning, the level of blood glucose will always be high. Since body is using glycogen for normal function, there will be no breakdown of body fat. This will lead to lower ketones.

If you want to learn more about dawn phenomena. Read this.

Since, I did not see any sign of ketosis in the morning. I hopped on my treadmill and ran for 6 miles at a relatively faster pace (7:15/mile). I then checked my blood biomarkers again and sure enough, I had some ketones. You can see in the graph above that the level was 0.7 after the run. That made me a bit happy.

At lunch, the ketone levels reached 2.2 mmol. I was expecting that since my workout in the morning was at moderate intensity and I did not eat anything for almost 18 hours.

I went to do some more miles on treadmill at 3 pm and tested my blood again. Ketone levels at 3 pm was 2.9 and after 6 miles run it was dropped to 2.2 mmol.

I came home and tested the blood again after 24 hours into the fast. I was doing pretty good as far as optimal ketosis was concerned.

Day 2

Morning: Woke up and did ketone and glucose level. My ketone level was lower but still quite high (2.4 mmol). It was in the optimal ketosis range.

Noon: Checked my ketosis level and it was now going up to 2.7 mmol. And went upto 3.8 mmol at 40 hours mark. I ran 4 slow miles in the afternoon and it came down to 3.2 mmol. My body was using fat as a primary source now. Since I started feeling hungry, I was drinking water at regular interval.

Experiment 2:

Day 1:

As mentioned earlier, I did this experiment only on eggs and coffee. People on internet, call it egg fast.

So, I was eating protein and fat but there was no carbohydrates at all. I did this with coffee because I drive to work for about an hour and never wanted fall asleep while driving.

Well, this turned out to be very interesting. As you can see in the graph 1, my blood ketone levels did not go above 0.7 in first 24 hours. It means I was in light ketosis. I mentioned in previous post that blood ketone levels range from 0.5-1.5 mmol is considered light ketosis. Anything between 1.5-3.0 mmol is considered optimal ketosis levels. Accordingly to Dr. Phinney and vVlek, one can reap maximum benefit of keto diet by having ketone levels in the optimal range. Ok, Lets move further into my egg fast data.

Day 2

To my surprise, it did not move up at all and mostly stayed below 1 mmol even after 32 hours into egg fast. Was my body using the protein and fat coming from eggs efficiently?

Was it directly turning into usable source and did not have worry too much about the stored fat?

At least the data takes us in the direction that eggs along with stored glycogen were being preferred on the egg fast which was not the case in experiment 1.

So, what we learn from the ketone levels at coffee and egg fasting?

Coffee fasting and exercise put me into optimal ketosis very quickly. Whereas, egg fasting and exercise kept me in very light ketosis.

Blood glucose data:

Experiment 1: Now lets have a look at the glucose level in experiment 1

Day 1

My glucose level increased slightly when I went for a run. My body used glycogen efficiently during a run. I have seen several times that my blood sugar level is higher just after a run or any other physical activity.

During the night time, it was higher as we can see the plateau (blue line) in the graph 2. But it was still well within the normal range.

Day 2

Blood sugar level started to come down sharply after 32 hours of coffee fasting. Possibly because my glycogen level was now almost empty.

My glucose level was around 64 mg/dL at hour 40 and that made me a little nervous because very low glucose level van be dangerous. However, it was not too bad. I checked online and found that is not worrisome. So, I hold on to it till I checked my levels again at 3pm. To my relief, it increased a bit to 67 mg/dL but still low.

Glucose level went slightly up so I felt comfortable in going for a 4 miles easy run on treadmill. Then ran 4 miles at easy pace. Checked my glucose again and It came back to normal range.

Graph 2: Variation of glucose in coffee and egg fast

My blood sugar level always stayed lower after 35 hours into the fast. It started to dive down sharply after hour 45.

I have ran 20 miles in two days and did not eat anything. My glycogen level should have been empty. Then how come my glucose was higher during the exercise. Was my body using muscles for glucose? I can not answer this question for sure. But I did not have any carb or glycogen left by 44 hours into the fast. So, most likely my body had started breaking down muscles for survival.

This means that I was in the starvation mode. My ketone level was above 3 mmol but not at the level of ketoacidois.

I drove home and checked the blood level again. Blood sugar was in normal range and ketones were higher than optimal. I felt really hungry in the afternoon and decided to wait till 7 pm (48 hours).

I was looking at the food on the table and it was 6:30 pm. Next 30 minutes was the longest period I have been waiting for-really. I was counting seconds to eat at 7 pm.

I ate some pecans and peanuts initially and then had a full carb meal. It tasted so good. I ate everything that was in front of me.

Experiment 2


My glucose level on egg fast remained very consistent for most of the duration. As you can see the red line in graph 2 above, it stayed almost uniform for first 35 hours

Day 2:

Glucose level started diving down after 40 hours into ketosis. This is similar to the coffee fast. At this point looks like my glycogen has almost depleted and body was either producing glucose from the egg protein or had started to break down muscles.

Combining ketone and glucose and find out GKI

More data can give you more insight, that is why data science has been a great topic these days. Therefore, looking at ketone and glucose data separately wont provide you complete picture. Now, lets combine them together and find an Index that involve both parameters. This is called Glucose Ketone Index (GKI). How do you calculate this? Just divide the glucose value in mmol by the ketone values in mmol.

By doing so, we will get a constant number. That is your GKI. But how much my GKI value should be?

There is range of GKI that you need to have for maximize your fat burning capacity and that range is

  • More than 9-No ketosis-your body is using glucose as main source
  • 6-9-Light ketosis-There are a few ketones flowing in the blood
  • 3-6-Moderate ketosis-Good amount of fat buring in this range
  • 1-3- High ketosis-Optimal level of ketosis
  • Less than 1-Super high ketosis and can be used for therapetic purposes

Let us now dive deeper into the two experiments that we performed and find out where I stood during the 2 days fast period.

As show in graph 3, my GKI was in the high ketosis range during coffee only fasting. Egg fasting kept me into light ketosis most of the time and even no ketosis for the first 12 hours and at hour 36.

Graph 3: Change of GKI in coffee and egg fast

Let us now talk about two other blood markers that i quantified during the fasting process.

HCT and Hemoblobin levels

Thanks to state of the art stripes from Keto-Mojo, I was able to measure two more biomarkers on my fasting experiments. These were Hematocrit (HCT) and Hemoglobin. Honestly, I have never heard of Hematocrit in the past. So I did some reading to find out.

Here is my HCT and hemoglobin data for the coffee fast experiment

HCT and hemoglobin data on coffee fasting

Both biomarkers stayed in the normal range till hour 40 on my coffee fast. However, I saw a sharp jump in my hemtocrit level around hour 44 (indicated by the arrow in the graph). Though, it was within the range, I wondered why it went upto 50% around that time and came back down.

Was my body producing more red blood cells when I was starving and pushing my body to run more? I do not know for sure but will read more about it. If you have an idea, please let me know.

HCT and hemoglobin data on egg fast

Interestingly, my HCT was lower on the egg fast. This has also fluctuated more than it had in the coffee fast experiment.

Even more interesting was that it was very low at hour 44 when I did 4 miles.

Low HCT means that the person has low level of red blood cells. When it drops below 33% after exercise on the egg fast experiment, I was little worried.

Is my diet having effect on this level or am I not taking enough iron? Vitamin B12 and/or folate? I do not have answer to that but would certainly love to find out this by doing this.

  1. Taking food that has enough iron
  2. Foods with vitamin B12
  3. or Iron supplement

I did not freak out too much because my HCT level was within the normal range during the whole duration of fasting.

Although, the levels of hemoglobin stay almost in the usual range. Sometimes, lower but mostly in the normal range.

Combining HCT data of coffee and egg fast

Since, I observed different data of HCT in both experiments. I decided to plot them together and have a closer look.

You see a dip in HCT level on egg fast at hour 21. However it stayed almost constant for the coffee fast.

The data point at hour 44 made me think to plot them together and have a closer look. Here is the chart. Look, how HCT spiked at hour 44 after the 4 miles in experiment 1 and how it dipped in the egg experiment at the same time. Is this just one data point or it really has to do something with fasting with coffee and egg. I need to dig deeper. Nevertheless, It was fun to observe this.

Conclusion and key take away

My ketone and glucose data along with HCT, hemoglobin and GKI gives some interesting data. This also shows how exercise and food can affect the ketosis. Here is the summary

  • I reached optimal ketosis of more than 1.5 mmol blood ketones within 18 hours of fast (only coffee)
  • The level of ketone bodies also vary on the time of the day, if you take the readings in early monring, they will be low. In the afternoon around 4-5pm, one can find maximum ketones. So if anybody ask me, what is the best time to check ketone levels? I would suggest the late afternoon time.
  • Egg fast kept me in light ketosis but but level always remained between 0.5-1.1 mmol of ketones
  • My glucose level remained within the range most of the time. It went below normal after 40 hours of fast.
  • My GKI shows that I was in the high ketosis during coffee fast and light ketosis during the egg fast.
  • My HCT and hemoglobin levels remain almost constant during the 48 hours time but at hour 44, HCT spiked on coffee fast and dropped on egg fast. This rise and drop is real or just a data point? I do not know the answer. But future self experiments will help me answer this question.

Please feel free to ask question, comment and suggest anything that I am missing while writing this article.

If you like this article, please share this. Want to hear more about self experiments and ultra running in future? Subscribe to my email list.

I would like to thank Keto Mojo for providing me ketone and glucose test stripes along with Keto-Mojo meter. You guys are as awesome as your products

Where can you buy Keto products?

You can buy keto products using this link . Use coupon code MALIKSMOBILITY to get 10% off on your purchase.

Disclaimer: I am an affiliate of Kiss My Keto. This means that I will get little commission if you purchase items from Kiss My Keto using this link. Please use the coupon code MALIKSMOBILITY to get 10%.

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