You might know the feeling. You read a sentence three times and still don't understand it. You walk into a room and forget why. You try to focus, but your thoughts feel slow and hazy. Many people call this brain fog: a feeling of mental cloudiness where concentration, memory, and clear thinking temporarily don't function as well. It's not an official medical diagnosis, but a term increasingly used to describe a common experience. It's a feeling where your brain simply isn't operating at full capacity.

And that's not so strange. In a world of constant stimuli, little sleep, stress, and heavily processed foods, our brains have much more to process than they were evolutionarily designed for.

What exactly is brain fog?

Brain fog describes the feeling that your brain is temporarily functioning less clearly. Processing information takes more effort, and simple tasks can suddenly demand more energy.

Typical characteristics include:

• difficulty concentrating
• forgetfulness
• mental fatigue
• difficulty thinking clearly
• the feeling of "not being entirely present"

Many people describe it as if their head is working slower, as if there's literally a layer of fog over their thoughts. The interesting thing is that brain fog rarely has one clear cause. In most cases, it arises from a combination of factors that collectively impact how efficiently the brain works.

Possible causes of brain fog

Poor sleep

Sleep is one of the most important recovery periods for the brain. During deep sleep, waste products are removed from the brain via the so-called glymphatic system.

When sleep is too short or irregular, processes such as memory and focus can noticeably deteriorate. Many people notice that brain fog often occurs after a period of poor sleep or a disturbed circadian rhythm.

Blood sugar fluctuations

The brain is one of the most energy-intensive organs in the body. Although it only accounts for a small percentage of body weight, it consumes about 20% of the total energy.

When food consists mainly of simple carbohydrates or highly processed products, blood sugar can rise quickly and then fall again. These fluctuations can lead to energy crashes, reduced concentration, and a feeling of mental sluggishness.

Stress and mental overload

Chronic stress continuously activates the body's stress system. The hormone cortisol plays an important role in this. Prolonged elevated stress levels can affect brain regions involved in memory and focus, such as the hippocampus and prefrontal cortex. When the nervous system is continuously "on," it can manifest as mental fatigue and brain fog.

Gut health

More and more research shows a strong connection between the gut and the brain, often called the gut-brain axis.

The gut microbiota plays a role in inflammatory processes, neurotransmitter production, and immune regulation, among other things. When the gut becomes imbalanced, for example due to stress, diet, or antibiotics, this connection can also affect cognitive functions and mental clarity.

Want to read more about gut health? Then read this blog.

Oxidative stress

During normal bodily processes, free radicals are formed: reactive molecules that can cause damage to cells when they are out of balance. When there are too many of these molecules and the body has insufficient antioxidants to neutralize them, oxidative stress occurs.

The brain is particularly sensitive to this because it:

• uses a lot of energy
• is rich in fatty acids
• is highly dependent on good blood flow

Antioxidants from food help protect cells from this damage. Think of foods like berries, green vegetables, cocoa, and herbs.

Nutrient deficiencies

Various micronutrients are needed for a well-functioning brain. Vitamins and minerals play an important role in processes such as energy production, nerve function, and neurotransmitter synthesis.

Examples of nutrients involved here are:

• B vitamins (energy production and nerve function)
• magnesium (nervous system and relaxation)
• iron (oxygen transport and energy)

When the body does not get enough of these through diet, it can contribute to fatigue and reduced mental energy. Sufficient micronutrients through diet or supplements can therefore play a role in supporting various bodily processes.

What can you do about brain fog?

Because brain fog often arises from multiple factors simultaneously, the solution usually also lies in lifestyle. Small adjustments in diet, exercise, sleep, and circadian rhythm can already make a big difference.

Nutrition

Your brain needs a constant and stable energy supply. Therefore, diet plays an important role in mental clarity.

Ensure stable blood sugar

Meals consisting of proteins, healthy fats, and complex carbohydrates provide a more stable energy release than simple sugars.

A practical meal structure could be, for example:

• protein source: eggs, fish, yogurt, grass-fed meat
• healthy fats: olive oil, avocado, nuts, fatty fish
• complex carbohydrates: seasonal vegetables + fruit

This helps to prevent energy spikes and crashes. Also read: 5 hacks to keep your blood sugar stable

Eat enough healthy fats

The brain consists largely of fats. Especially omega-3 fatty acids, such as DHA and EPA, are important building blocks for brain cells. Sources include: fatty fish (salmon, mackerel, sardines), shellfish, omega-3 supplements

Consider micronutrients

Micronutrients like B vitamins, magnesium, and zinc play a role in energy production, nerve function, and brain processes. A diet rich in whole, unprocessed foods helps ensure you get enough of these nutrients.

Eat antioxidant-rich foods

Antioxidant-rich foods are primarily found in colorful, whole foods. Think of berries such as blueberries and raspberries, green vegetables such as spinach, kale, and broccoli, but also cocoa, dark chocolate, and herbs like turmeric and cinnamon. Green tea and a wide variety of fruits and vegetables also provide various bioactive compounds such as polyphenols and flavonoids that contribute to cell protection.

In addition, there are specific antioxidants such as astaxanthin, a carotenoid naturally found in salmon, krill, and shellfish, among others. This substance is being researched for its role in protecting cells against oxidative stress (1).

By regularly eating these types of foods, you support the body's natural protective mechanisms and, by extension, brain function.

Exercise

Exercise not only affects the body but also directly affects the brain.

Regular exercise can improve blood flow to the brain, reduce stress, support concentration, and increase mental energy.

It doesn't have to be extreme. For many people, these principles work well:

• daily walking
• regular strength training
• short movement breaks between work blocks
• exercising outdoors in daylight

Even 15-20 minutes of walking can help clear the head.

Circadian Rhythm

The human body operates on a circadian rhythm. When this rhythm is disturbed, it can affect energy, hormones, and cognitive functions. More information about your biological clock can be found here.

Sleep as a foundation

Many forms of brain fog ultimately have a strong relationship with insufficient recovery during sleep. Also read: 5 ways that help you improve your sleep.

Plant extracts and cognitive support

In addition to lifestyle, there is also growing interest in plant extracts and bioactive compounds that can support the body. It is important to understand that these substances are not a quick fix. They often work subtly and in interaction with the body, and their effect depends heavily on factors such as diet, sleep, stress, and gut health. Some plant extracts often studied in relation to brain function include:

Lion's mane

Lion's mane (Hericium erinaceus) is a medicinal mushroom traditionally used in Asian medicine. Research suggests that compounds in lion's mane may be involved in processes related to nerve growth and brain function (2).

Bacopa monnieri

Bacopa is an herb from the Ayurvedic tradition that is often studied in relation to memory and learning ability (3).

Rhodiola rosea

Rhodiola is often used as an adaptogen: a plant that can help the body cope with stress and mental fatigue (4).

Plant extracts contain a complex array of bioactive compounds and are therefore usually seen as supporting physiological processes, not as treating complaints. The foundation always remains lifestyle. Without sufficient sleep, nutrition, and recovery, no extract will make a difference.

Brain fog is often a signal from the body

Brain fog is rarely an isolated problem. It usually arises from a combination of factors such as sleep deprivation, stress, diet, and overstimulation. The good news is that precisely because of this, lifestyle interventions can often make a big difference.

When diet, exercise, sleep, and circadian rhythm become better aligned, many people notice that their mental clarity gradually returns. Your brain functions best when energy, recovery, and rhythm are in balance. In many cases, brain fog is not a coincidence. It is a signal that your body is out of balance and needs attention, not suppression.

References

1. Kim, S. H., & Kim, H. (2018). Inhibitory Effect of astaxanthin on Oxidative Stress-Induced Mitochondrial Dysfunction-A Mini-Review. Nutrients, 10(9), 1137. https://doi.org/10.3390/nu10091137
2. Cha, S., Bell, L., Shukitt-Hale, B., & Williams, C. M. (2024). A review of the effects of mushrooms on mood and neurocognitive health across the lifespan. Neuroscience & Biobehavioral Reviews, 158, 105548. https://doi.org/10.1016/j.neubiorev.2024.105548
3. Calabrese, C., Gregory, W. L., Leo, M., Kraemer, D., Bone, K., & Oken, B. (2008). Effects of a Standardized Bacopa monnieri Extract on Cognitive Performance, Anxiety, and Depression in the Elderly: A Randomized, Double-Blind, Placebo-Controlled Trial. The Journal of Alternative and Complementary Medicine, 14(6), 707–713. https://doi.org/10.1089/acm.2008.0018
4. Ma, G., Zheng, Q., Xu, M., Zhou, X., Lu, L., Li, Z., & Zheng, G. (2018). Rhodiola rosea L. Improves Learning and Memory Function: Preclinical Evidence and Possible Mechanisms. Frontiers in Pharmacology, 9, 1415. https://doi.org/10.3389/fphar.2018.01415