Blood sugar explained + 7 tips for your health

The topic 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 partly be used as an indicator for 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. But even without this tool, our organism gives us signals that indicate blood sugar fluctuations or a stable level.

Our bloodstream supplies our cells with sugar

Blood sugar is the concentration of simple sugar glucose in the blood. This value can be measured and is indicated in mg/dl or mmol/l. Our body cells need glucose as an energy source and as a basic substance for metabolic processes1. It is obvious that there must always be a certain amount of glucose in our blood for these continuous processes to function. However, it must also not be too high, as this could, to put it simply, clog the blood. Fortunately, in our organism nothing is left to chance, so various hormones regulate our blood sugar level. They work by sending signals to our cells to absorb or release glucose.

At the end of the article we learn in detail how to keep blood sugar constantly lower with the right foods and everyday aids.


How do we intake sugar?     

Especially when we eat carbohydrates, our blood sugar rises relatively significantly. Carbohydrates can be found in foods in the form of single, double or multiple sugars (starch). Simple sugars such as glucose (grape sugar), fructose and galactose are often found in sweets or fruits. Lactose (milk sugar) and sucrose (crystal sugar) belong to the group of dual sugars. More complex polysaccharides in the form of starch are found in potatoes, cereals, pulses and vegetables.

Our intestines can only absorb simple sugars, which means that during our digestive process, which begins when chewing in the mouth and ends in the intestines, the double and multiple sugars have to be broken down. The more complex the carbohydrates and the more they are "wrapped" (e.g. in indigestible fibre or fat), the longer and more evenly the sugar is absorbed from them. The fastest we absorb sugar directly from sugary drinks.

For our blood sugar level, only glucose is important. Although fructose and galactose also enter the bloodstream, they are passed directly to the liver, which must first convert these two types of sugar - often into fats, which are then stored in body fat. But if our blood sugar is low and our body urgently needs energy, a fruit juice that contains a lot of fructose helps because this is then converted incredibly quickly by the liver into direct energy.

If we have now absorbed a larger amount of glucose, our blood sugar will rise. If it has reached a level that is above the normal requirement needed to supply the cells, the excess sugar must be removed. This is regulated by the hormone insulin, which is described in more detail in the section after next2.


What is a normal blood sugar level and how can it be measured?  

The glucose concentration in the blood can be determined with various measuring devices. Of course, this can be done at the doctor's office using a laboratory sample. However, for diabetic patients, who have to check their values constantly, more uncomplicated methods have been developed. For example, one can use a sensor with a small needle attached. This detector is now very small and is attached to the back of the upper arm, for example. The sensor then sticks to the skin - usually for two weeks - and the fine needle, which is not noticeable or disturbing, is in constant contact with the blood. The sensor data is then transferred to a connected blood sugar meter.

Meanwhile, there are even apps that replace the device, so that it can be tracked conveniently with a mobile phone.

As described in the first section, the level is given in mg/dl (milligrams per deciliter) or mmol/l. In Germany, most of the times, mg/dl is used, but for the sake of simplicity, we will limit ourselves to this here.

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. We speak of diabetes when the blood sugar level on an empty stomach is above 126 mg/dl and above 200 mg/dl after a meal3. More on this topic will follow in a later section of this article.


Insulin – the storage hormone

If our blood sugar rises, the pancreas is stimulated to release insulin into the bloodstream. The hormone is then taken to the cells where it binds to receptors on the cell membrane. This causes the glucose transporters inside the cell to reach the cell membrane where they are incorporated so that the excess glucose can flow in from the bloodstream.

In simple terms, insulin can be thought of as a secret knock on the door, whereupon the bouncer, in the form of the glucose transporter, opens. Once the glucose has reached the interior of the cell, it is converted into its storage form, glycogen, and stored there. These glycogen stores, which we have in liver and muscle cells, have - unlike fat cells - a limited capacity. If they are already full, our liver begins to convert sugar into fat and store it in this form4. This is also one reason why sugar can make us fat.


Glucagon, adrenalin, noradrenalin, somatotropin and cortisol increase blood sugar

The glucose level in the blood cannot only be increased through food intake, because then we would have a problem if there is nothing to eat for a few hours or days. For our ancestors this was the case time and again. Glucagon is the antagonist of insulin and thus the hormone of energy supply. It gives the liver cells the signal to convert stored glycogen back into glucose and release it into the blood. Glucagon also gives the corresponding signal for the transformation of stored fatty acids into sugar4.

Cortisol is one of the hormones that our body releases in a state of stress. It increases the blood sugar level so that we have enough energy to cope with stress. Our organism does not distinguish whether this is - as in primeval times - the escape from a bear or, as today, the pressure we are exposed to in the office when we have to do three things at once. If we have an intolerance to a foodstuff, the immune reaction it produces also promotes the release of the stress hormone, which can ultimately lead to a rapid rise in blood sugar. More on these topics will follow in the continuation article in which I report on my blood sugar experiment.

Adrenaline, noradrenaline and somatotropin are also hormones whose signals promote the transport of glucose from the stores into the bloodstream. The function of these hormones is not described here in detail due to their high complexity.


Health and blood sugar levels – Type 2 diabetes and the influence of our diet

As explained above, different foods have a different influence on the blood sugar increase. A constantly elevated blood sugar level and extreme fluctuations have negative consequences for our health. On the one hand, this is due to the fact that excess sugar is converted into fat and stored, which promotes obesity, cardiovascular disease and other health problems.

On the other hand, the glucagon-insulin continuum is out of balance: every time the blood sugar rises excessively, a correspondingly large amount of insulin is released. Its receptors on the cell walls disappear, so to speak, due to their extreme wear and tear, because they can no longer regenerate. In the long term, this can lead to the cells no longer receiving signals to admit and store glucose. As a result, the glucose remains in the bloodstream and must then be transported away via the kidneys so that it can leave the body with the urine. This also leads to overloading and does not solve the problem. In addition, the body may also produce less insulin because the pancreas is tired from years of high production. First, we speak of insulin resistance, then of the disease Diabetes Mellitus Type 25.

Even if you are not at risk for diabetes, it makes sense to keep your blood sugar as stable as possible so that there are fewer extreme fluctuations up and down. This is because they promote the release of signals from others by means of a rat tail, which makes us sluggish and robs us of our concentration.


What can I do to keep my blood sugar stable?

To keep our glucose levels stable and to keep us concentrated, focused and energetic all day long, the following can be done:

1. Eat protein, vegetables and good fats for breakfast. The first meal of the day can stabilize the blood sugar to a certain degree for the whole day. You can find more about this in the article "the perfect breakfast".

2. Avoid sugar drinks and foods containing single and double sugars. Instead, eat more complex carbohydrates, mainly in the form of vegetables and otherwise as rice, potatoes, quinoa, buckwheat or millet. Indigestible fibre slows down digestion so that the broken-down sugar from the complex carbohydrates is absorbed very slowly.

3. Snacks made from good sources of fat, protein and fibre prevent ravenous appetite attacks in which you reach for quickly digestible sugars and thus start a vicious circle for the insulin rollercoaster.

4. Consume food that stabilizes blood sugar: Grapefruit, cinnamon, green tea, dark chocolate, coffee, turmeric, coconut, apple vinegar, lime juice and lemon support a stable glucose level, especially through their micronutrients.

5. Avoid stress, because this causes the blood sugar to rise due to the increase in cortisol. You can learn to deal better with stressors. Read more about this in the article about "the proper mindset".

6. Do More sport and exercise: exercise has a positive influence on stable blood sugar levels. After a carbohydrate-rich meal, a walk is always a good decision. More intensive sports activities promote insulin sensitivity, which can prevent insulin resistance.

7. Listen to the signals of the body and interpret them correctly:
After which meal do you feel weak and need to take a nap? When do I get ravenous appetite attacks? When do I feel good? Each body is individual and it is possible that certain foods can cause a rapid rise in blood sugar in one person but not in another. This is partly genetic, so we do not have an unrivalled impact on it.

In the next article I will describe my blood sugar experiment in accordance with the 7th point. For two weeks I measured the glucose level with a sensor and tried many different foods.


1 Doccheck Flexikon: Blutzucker. [; 10.05.2020].
2 Zschokke, Samuel (2017): PPP Ernährung und Verdauung. Basel: Universität Basel. Professur für Biologie.
3 Diabetes Ratgeber: Laborwerte: Blutzucker (Glukose). [; 10.05.2020].
4 Bütikofer, Markus; Hopf, Zensi; Rutz, Guido; Stach, Silke und Grigoleit, Andrea (2015): Humanbiologie 1: Grundlagen, Stoffwechsel und Abwehrsysteme. S. 61-6.
5 The Simple Club: Diabetes Mellitus Typ 2: [; 10.05.2020].


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.

Häufig gestellte Fragen

How high may the blood sugar be?
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.
At what level does the blood sugar level become dangerous?
One speaks of a diabetes disease if the blood sugar level on an empty stomach is above 126 mg/dl and above 200 mg/dl after eating. However, one should differentiate somewhat here: Due to the fact that certain foods can cause immune reactions, the blood sugar can often rise very high after consumption without necessarily being a blood sugar disease. This is because such a reaction releases stress hormones, which additionally ensure that sugar is released from the storage tanks into the blood.
What values are measured for blood glucose in order to determine it accurately?
Blood sugar is the concentration of the simple sugar glucose in the blood. This value can be measured and is indicated in mg/dl or mmol/l. Diabetics today usually wear a sensor that has a fine needle in the front that is shot under the skin when it is attached and is held in place by a skin-friendly adhesive. It can then be displayed and checked using a connected measuring device or an app on a mobile phone. However, these values often deviate slightly. The doctor can determine them more accurately with a proper blood sample.
When should you normally measure your blood sugar?
In the morning directly after getting up before eating, you can measure the sobriety value. Diabetics and people who want to measure their blood sugar should do so before meals and 1.5 - 2 hours after eating.
What lowers blood sugar?

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