Should you check your blood sugar? The two-week experiment

The subject of blood sugar should not only be known to diabetics, because blood sugar fluctuations have an influence on our body fat, our energy level, health and it can be used in part as an indicator of food intolerances. Nowadays, anyone who wants to get to know their body better using this tool could track their glucose level with a sensor from the comfort of their own home without a visit to the doctor. This is exactly what I tested with a blood glucose meter for two weeks and got to know my body a little better.


Why measuring blood sugar even though one is healthy? A short review of the first article:

As a healthy person, measure and monitor my blood glucose? I have dared to experiment on my own and checked my blood sugar at regular intervals during the day to show you what this value can tell you about your health.

In the last blog post the topic of blood sugar was explained in more detail. The article provides the basic knowledge about hormone regulation around glucose levels, diabetes and what effect all this has on our health, performance and body fat. Fact is: Blood sugar should be kept as stable as possible and should not fluctuate too much up or down, so that the hormones that are important in this context are not overloaded. This can be achieved through diet, exercise and the right lifestyle. You can find more detailed information on this in the article on blood sugar itself - this would be highly recommended here as prior knowledge.


Why should I measure my blood glucose even though I am not a diabetic?

Since I have been dealing with the topic of blood sugar and insulin for quite some time, because it is an important basic knowledge in nutritional counseling, I wanted to examine the whole thing more closely. It is true that you can learn a lot about the topic in medical and biology textbooks and scientific literature. For example, how blood sugar rises depending on the time of day or meal, and how the hormone insulin behaves accordingly, can be found out quickly, but every body is individual.
In practice, everything can look a little different, because genetics, intestinal health, exercise and many other factors can have an influence on blood sugar. Measuring blood sugar can therefore also be interesting for healthy people who want to test themselves.

Through the experiment I was able to get to know my body better again, because now I know that there are actually some foods that are less good for me than others. I was actually very surprised about how extremely the sweet potato makes my glucose level soar, when it is always advertised as a stabilizing agent for blood sugar. Basically, this will be the same, but not for me personally. More about this follows further down in my results table.


Measuring blood sugar: The methodology – blood glucose meter in the app combined with the sensor 

For my experiment I have chosen an innovative and uncomplicated method. In the internet I could order the sensor from the company, which can measure the blood sugar. It can be easily attached to the upper arm at home with the included applicator. Like a stamp you press on the applicator, which then presses into the small round sensor on the skin. It has a fine needle at the front, which is shot under the skin during application and is held in place by a skin-friendly adhesive. The application does not hurt at all, you do not feel anything poking under the skin. The sensor does not disturb at all and holds well even when showering or doing sports. You should only be a little careful not to get stuck when taking clothes off and on. 

You can then activate the tracker via an app. To synchronize the meter, you just have to hold your mobile phone over the spot on your arm and the app will tell you the glucose value. Furthermore, a statistic curve shows what happened in the time before. So, you can see from the graph and additionally the exact measured values in mg/dl how your blood sugar fluctuates during the day and at night – check the following figure:



The results – my most important conclusion about measuring blood sugar

I have written down the most important measured values from the app's data. Actually, the focus was initially on the individual foods, because I was interested in what makes blood sugar rise more and what makes it rise less or more slowly. Once again, I had to find out how complex our body is and that not just the food itself plays a role, but other factors such as stress levels or the combination of foods influence it. Above all, I was able to conclude from the data that the first meal of the day can actually stabilize blood sugar for the entire day.

This has once again confirmed to me the crucial role of a proper breakfast, about which you can read everything again in the corresponding article.


Summary and interpretation of data when measuring blood glucose

In the following table I have summarized the most relevant measurement data for me and have written a possible explanation for it. This is based on my biochemical understanding of the topic, taking into account, among other things, the points on hormonal regulation from the first article on this topic. Nevertheless, it must be said at this point that the explanations and my conclusions from them are mainly hypotheses.

Here is a brief explanation to help you understand the measurement data: We use the unit milligram per deciliter of blood (mg/dl) for the measurement of the blood glucose. According to science, a healthy person should not have a higher sugar level than 100 mg/dl when sober (i.e. after getting up, before eating).

Two hours after a meal, blood sugar is usually up to 140 mg/dl. Depending on whether you have eaten a meal that is very rich in carbohydrates, your glucose level may be slightly higher. One speaks of diabetes when the blood sugar level on an empty stomach is above 126 mg/dl and above 200 mg/dl after a meal.


Measurement results

Potential explanation

Right after waking up the value was around 100mg/dl. On working days, it rose to 115mg/dl within 30 minutes before breakfast - on free mornings the increase was 10mg/dl lower!

Overnight blood sugar stabilizes, but when we wake up the stress hormone cortisol is released, because it activates our system. This increase causes sugar to be transported into the bloodstream, as our cells need to be supplied with energy. On working days more stress hormones seem to be released because more action is required!
For me it felt like positive stress, I was directly awake, motivated and focused, which is why this increase is natural and sensible. However, people who feel more negative stress in the morning may find it even more valuable and should incorporate a morning routine that will let them start the day with a little more serenity.

Red meat with vegetables and good fats stabilizes my blood sugar for the whole day.

A purely vegetable breakfast lets my blood sugar rise from 100 to 130 to 140mg/dl within 30 minutes - even though it is low in carbohydrates!

It was very clear to me. If the first meal wasn't meat, fat & vegetables, my blood sugar jumped up and down with every snack and meal - except when I had steak with vegetables at lunchtime, for example. Then my glucose level was very stable again for the rest of the day.

For me this means that meat for breakfast is good for me. But that does not mean that this is the case for everyone!

Intermittent fasting from 16h overnight until noon the next day had a very positive effect: My blood sugar remained very stable after the small increase in the morning after getting up - between 95 and 110 mg/dl.

With fasting 2-3 times a week I already felt very well before: My energy level and concentration are always very good during this time and I feel regenerated afterwards. Apparently, fasting also gives my blood sugar hormones the chance to recover.
I think fasting could have a positive effect on most people.
Anyway, I would like to go into this topic in more detail in my next article.

Sweet potatoes drive my blood sugar incredibly high; it has risen from 113 to 193mg/dl (!) within 30 minutes! Another 45 minutes later the value was at 78 mg/dl. Normal potatoes increased it to a maximum of 142 mg/dl!

After this rapid and extremely high glucose increase, I had a total midday low and had to lie down for a while. No wonder, because my blood sugar went on a wild rollercoaster ride! After a meal with normal potatoes it was not like that at all and my energy level remained constant. Obviously, my genetics are not made for the tuber from South America, even though it is actually a superfood!

Everyone has to find this out for himself. I assume that people with southern roots react well to sweet potatoes. The blood sugar levels associated with sweet potatoes were far from the healthy norm!

Even complex carbohydrates late in the evening (after 8 p.m.) cause my blood sugar to rise sharply in the first sleep phase to up to 150 mg/dl, then it drops to below 100mg/dl within about 30 minutes.

With the production of melatonin (sleep hormone) in the evening, which begins 2 to 4 hours before going to bed, a gene is activated which shuts down the insulin secretion. As a result, less glucose is brought from the blood into the cells and blood sugar rises more strongly1.
If it becomes too high, insulin must be activated again - more than is actually good. This can disrupt our biorhythms and in the long-term lead to problems with insulin production.
That's why I would recommend everyone to stop eating for 3-4 hours before going to sleep. According to Dr. Rhonda Patrick, this alone has a long-term positive effect on the blood sugar and insulin balance1.


Studies and values are mostly based on investigations of diabetes patients

I would like to note briefly that almost all available data on glucose levels in diabetes studies have been generated. This is probably due to the fact that the investment is worthwhile here, because one wants to determine therapy measures for patients who have fallen ill, because these bring the companies profits again. Studies involving athletes and healthy people are therefore often of no interest to the investors in the studies. That is why I could only determine that the blood sugar level should normally not be higher than 140 mg/dl 2 hours after a meal. But what should happen during these two hours is relatively unclear. To make sure that enough insulin is produced to slowly stabilize the blood sugar level after the two hours, this indication makes sense.

But it would be interesting to know how high the value may rise shortly after the meal. In my extreme increase after the sweet potato, the value had returned to normal at 110 mg/dl after the two hours, but I am convinced that the extreme high and low is still not desirable. In the long term, this could develop into a problem with the insulin receptors if they are repeatedly overloaded by such increased values.


Measuring blood sugar – the conclusion of the self-experiment

I recommend to all those who want to get to know their body even better to carry out the blood sugar experiment on themselves. My data is a good example of the fact that despite an already very conscious diet, a healthy, fit body and a low body fat percentage, things can still be individually optimized. A stable blood sugar level is crucial for health, performance, body fat reduction and sleep. Since different people actually react differently to different foods, the Blood Glucose Meter tool is a simple solution for home users to further adjust their diet and lifestyle.

I tracked the Freestyle Libre 2 via the app, which for me was the cheapest and easiest option.

In case of doubt, never rely solely on your own tests or measurements and always consult a doctor or trained nutritionist for safety reasons if you discover irregularities in your blood sugar! I wish you a great success with your diet, your health and a balanced lifestyle.



 1 Patrick, Dr. Rhonda (2019): Late-night eating and melatonin may impair insulin response. Found my Fitness [; 31.05.20].


Ines Schulz
Ines Maria Schulz, geboren am 01.12.1992 in Basel, Schweiz hat auch dort den Master Of Education in Biologie und WAH abgeschlossen, womit sie den Grundstein für das Verständnis von Physiologie und Anatomie sowie Ernährungslehre gesetzt hat. Zudem ist sie ausgebildete Sportlehrerin für die Grundschule. Seit zwei Jahren ist sie Coach bei MTM Personal Training, dem erfolgreichsten Personal Training Studio in Berlin. Dort unterstützt sie täglich Kunden, die ihr maximales Potential bezüglich mentaler und physischer Gesundheit und ihrer Leistungsfähigkeit ausschöpfen möchten. In Kooperation mit Ärzten wie Dr. Dominik Nischwitz und einem Labor für Darmgesundheit sowie dem ständigen Austausch im Team kann sie ihre Kunden optimal über Training, Ernährung, Mikronährstoffe und Lifestyle beraten. Für MTM hat sie bereits ein Frühstücksbuch und einen grossen Teil eines Lifestyle Booklets verfasst. Zudem schreibt sie wöchentlich den Newsletter, in dem Ernährungstipps und von ihr kreierte Rezepte veröffentlicht werden. Ines hat bei verschiedensten erfolgreichen Coaches und Fachpersonen Seminare und Zertifikate absolviert und erweitert stetig ihre Kompetenz. Für Supz Nutrition ist die junge Trainerin seit Januar 2019 mit dem Verfassen von Blogartikeln aktiv.

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