How chronic stress leads to obesity and disease

Claudio Sachar

18. Mar 2021

Hello everyone and welcome to my post that will show you the enormous impact your stress level has on your nutritional behavior and consequently on your body. These insights will change your view on the connection between stress and nutrition forever! So let’s get started!

Our brain is fascinating, isn’t it? It is with this organ that we naturally solve complex problems, remember precious moments or lose ourselves in daydreams. From childhood, it allows us to develop a personality piece by piece, which is ultimately a puzzle made up of everything we have learned from and experienced with other people. Our brain makes us happy and proud: For example, when we have once again prepared a super healthy and delicious meal or have completed a successful workout. But sometimes it also gets in our way or drives us crazy: For example, when our thoughts prevent us from daring to do great things, or when they constantly revolve around the same almost unsolvable problem – we really „let ourselves think“. For centuries, we have been trying to better understand what goes on in our heads – and yet we are still at the beginning when it comes to understanding the countless processes and connections in this highly complex organ.

Why is our brain selfish?

To ultimately understand what negative effects chronic stress can have, let’s start at the beginning and first take a closer look at the human brain’s energy supply. It is – and this may come as little surprise – in first place when it comes to the priority of energy allocation. Our brain consumes an average of 20 percent of the energy available in the organism, even though it makes up only about 2 percent of a person’s mass. In doing so, it takes up over 60 percent of the circulating blood glucose, which is about 130g daily. Under acute or chronic stress, this proportion is even significantly higher!

In addition to glucose, our brain can also obtain energy from ketone bodies, which are formed in the liver from fatty acids. This is because, like glucose, they are allowed to pass the blood-brain barrier. Usually, however, their share in energy production is quite low, because nowadays we eat (more than) enough carbohydrates. The ketone bodies mentioned are therefore only used in a consistent low carb diet or a ketogenic diet. If the brain really still lacks energy during such a diet, the so-called gluconeogenesis takes effect, with whose help glucose is ultimately obtained from proteins. If our brain demands energy from our body, this is incidentally called brain pull. A mechanism that at any time leads to our command center being served before all other organs. This ability of the brain to influence the energy supply of the organism at the expense of the other organs in order to be sufficiently supplied with energy can definitely be called quite selfish. Therefore, the whole thing is also called the Selfish-Brain-Theory. By the way, this theory is based on the experimental evidence of more than 12,000 publications – so there is hardly any doubt about the egoism of our brain.

How does stress actually arise?

When our environment changes and becomes uncertain, we are confronted with the following crucial question: What courses of action can ensure our physical, mental and social well-being in the short term – and preferably in the medium to long term? Stress occurs in those people who cannot answer this question with certainty. This definition of stress is underpinned by the latest findings from brain research. Because these show that our brain basically strives to minimize uncertainty and surprises. This is because our organism does not suffer any damage only in a permanently safe environment. By the way, this process is called predictive coding. This generates exactly the information that allows us to make suitable predictions about future events – and bang … the future becomes predictable and we feel safe again. We just don’t like to live in uncertainty!

Every one of you who has ever been in a phase in their life where many things were still unclear will know the feeling of (chronic) stress. Whether it’s uncertainties at work, an upcoming job change, financial insecurity or problems in a relationship – all these things make us restless, put us in a permanent state of alarm, so to speak. Our brain reacts with a monitoring (hypervigilant) state, which is accompanied by increased information processing and an increased energy demand of the brain. Thus, it promises itself to resolve this situation in order to feel safe again as quickly as possible.

This fact is also made clear by Prof. Dr. Klaus Grawe in his research. He describes the need for orientation and control as one of the basic needs of every human being. In this context, one thing in particular is very exciting: There is a fine line between positive (still manageable) and negative (no longer manageable) challenges or uncertainties. Positive challenges lead to our brain being „made“ more ready to learn, to our own genetic potential being developed and to us being less susceptible to stress and psychologically healthier. Negative challenges, on the other hand, lead to the release of cortisol, among other things. This damages nerve endings in the cortex and can thus lead to the deletion of previously acquired (successful) behaviors. This and other negative brain-damaging effects of cortisol were shown by studies a long time ago.

How does our brain deal with stress?

Extensive studies in the context of Selfish Brain research have shown that our brain can develop two mechanisms to cope with chronic stress. The mechanism used here is very strongly dependent on genetic prerequisites. Because these divide us – in terms of stress reaction – into two types of people: Non-habituated and habituated. I would like to briefly describe these two types with their differences and similarities in as simple a way as possible. This will significantly change the way you see others and yourself. It will also become clear to you once again why an environment that is characterized by insecurity can have serious health consequences for you. So be sure to read on!


As mentioned above, in acute stress situations our brain switches to a monitoring (hypervigilant) state in which it consumes a disproportionate amount of energy. In chronic stress, this state must logically be maintained – that is, the brain requires more energy permanently. This can be achieved by increasing glucose and ketones, and increasing blood flow velocity in the brain. Fair enough. Now where is the problem here? Well – these measures are not without consequences: The increase in flow velocity causes arterial turbulence, which ultimately leads to increased blood pressure and, in the long run, to so-called adaptive vascular remodeling, which ultimately promotes atherosclerosis.

Furthermore, the increase in glucose and ketone supply, due to the dominant energy demand of the brain (brain pull), leads to the strong breakdown of subcutaneous fat. Subku-what? Subcutaneous fat is simply the fat under our skin that we like to have all over our bodies to keep us warm. „Yeah great! I want to get rid of that anyway!“ you will now say. Well, unfortunately, that’s not all. Because while your arms and legs are getting thinner – not least because muscle is also being lost to satisfy energy needs – your belly is getting fatter: the visceral belly fat that surrounds our organs is growing. Why is that now? Well – our body adapts in the long term and, due to chronic stress, always wants to have some kind of energy depot up its sleeve from which ketone bodies can be formed as an energy supplier. This is how the classic beer belly finally comes about. Of course, this phenomenon affects women just as much as men. It also explains, among other things, why quite slim people who are exposed to chronic stress and consequently have a medium to large belly increase their risk of heart attacks.


While the brain of non-habituants remains permanently highly reactive, the brain of habituants takes a somewhat more relaxed approach – it gets used to the chronic stress, so to speak, and becomes low-reactive in the long term. In this way, habituators avoid the above-mentioned consequences of the monitoring brain state. Well, that’s just great! If only we were all habituals! Unfortunately, we rejoiced too soon. Because there is also a catch here: The low stress reactivity restricts the essential ability of the body to be able to draw enough energy for our brain from the body (brain pull). So there has to be another solution! And that solution, unfortunately, is to get more energy from food to compensate for this problem. Unfortunately, a low brain pull also means that the amount of energy allocated to our brain from food is lower. And so, in chronic stress, habituals are basically quite hungry in order to ensure, as much as possible, the normal supply of energy to the brain. And that eventually leads to the accumulation of subcutaneous fat. In principle, this is not bad, as long as it remains with a few pads. But the pronounced hunger can easily lead to obesity and all its accompanying symptoms. So caution is advised.

We note: Habituates are people who show a repetition-induced attenuation of their stress response. Non-habituates, on the other hand, show no such modification.

So should I avoid stress as a matter of principle?

An excerpt from the Tagesspiegel, in which Prof. Dr. Gerald Hüther – an inspiring person in my eyes, successful neurobiologist and author – also comments on this topic, answers this question quite aptly:

„First of all, stress means nothing more than that the body is particularly ready to perform as a result of a perceived stress – a mobilization that is useful not only when there is a threat to physical integrity. Without stress, we would not develop at all. Stress strengthens, stress steels. An immune system that is always spared does not know how to fend off attacks. If you don’t suffer setbacks, don’t master crises, you can’t rise above yourself and develop confidence in your own abilities. In short, if you don’t experience stress, you can’t stand anything.“

Of course, this does not apply to chronic stress. This is because, in addition to the aspects mentioned above, it has many more negative effects on us – such as problems falling asleep or sleeping disorders, concentration difficulties, weakening of the immune system or ultimately the well-known burn-out syndrome. You should avoid chronic stress at all costs! Because without your health everything is nothing.

What does this mean now?

Fortunately, there are ways to reduce your stress or improve your stress management (stress response). One effective way is moderate-intensity exercise. For example, swimming, jogging, cycling or light weight training. But yoga, tai chi or quigong are also effective options. Meditation is a very effective measure, especially in terms of stress response. Finally, it is also important to develop an awareness of how I shape my life so that stress is only temporary and not permanent. Even though this dimension is the least controllable, because it depends less on yourself than on external, partly unchangeable, factors.

For more exciting content or services in nutritional counseling and/or stress management, feel free to check out my blog


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