Metabolic Health & Brain Fog

Brain fog describes symptoms that affect one's ability to think, like difficulty concentrating, memory lapses, and feeling mentally sluggish.

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Alicia Buchter
— Signos
Health writer
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Reviewed by

Alicia Buchter
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Updated by

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Science-based and reviewed

May 20, 2024
April 10, 2024
— Updated:
April 10, 2024

Table of Contents

Maybe you’re hard at work on a project, but you can’t seem to concentrate. Later, you’re in a conversation, and you can’t seem to remember what you were saying. Sometimes, it feels as though your mind is shrouded in nebulous clouds, and it takes effort to crystalize your thoughts. Most of us have experienced brain fog at one time or another, maybe after a night of too little sleep or a day full of too many activities. 

However, if brain fog is a common occurrence for you, there might be more going on than meets the eye. In this article, we’ll explain how chronic brain fog could be tied to your metabolism and what steps you can take to clear it up.


What’s Behind a Foggy Brain?

Brain fog is a colloquial term used to describe symptoms that affect your ability to think. As the name suggests, you could feel as though your thoughts are barely discernable and difficult to grasp. It can manifest as difficulty concentrating, memory lapses, and feeling mentally sluggish. You may feel confused, disorganized, and unable to focus or put thoughts into words. 

There are many reasons you might be experiencing brain fog. Some are as simple as not getting enough rest, being overworked, or being stressed. Other causes include pregnancy, menopause, some medications, depression, and some diseases like multiple sclerosis, lupus, or cancer and its treatment.

Ruling out causes of brain fog can be challenging, considering the myriad of factors that can affect cognitive functioning. However, if you are not experiencing hormonal fluctuations like during menopause or pregnancy and you don’t have a condition that may be affecting your cognitive function, the foggy brain you’re experiencing might be tied to your metabolic health. That’s right, your metabolism may be affecting your brain.

What Is Metabolic Health?

Woman multitasking: using laptop while holding a cup of coffee.

Your metabolism is the sum of all the chemical reactions occurring inside your body, which together amount to your body’s overall process of breaking down energy sources to create usable energy. These reactions and the products they produce enable the functioning of your cells and power your ability to walk, think, digest food, and see the world around you.

Your metabolic health is essentially a measure of how well your body is able to carry out this complex web of metabolic reactions. It includes to the overall state of metabolic processes in the body, including how efficiently it processes nutrients, regulates blood sugar, and manages energy. Those with good metabolic health are able to respond to food intake in a beneficial way. Their bodies break down food efficiently, balance energy expenditure and storage, and adjust to changes in physical activity and diet. When metabolic health is compromised, it can lead to various metabolic disorders such as obesity, type 2 diabetes, and metabolic syndrome.

Doctors use five markers to measure metabolic health. An individual is considered to be metabolically unhealthy if they meet at least three of the criteria, at which point they are diagnosed with metabolic syndrome. These metabolic markers relate to waist circumference, blood lipids, cholesterol levels, blood pressure, and blood glucose:

  1. Increased Waist Circumference: For men, a waist circumference greater than 102 cm.For women, a waist circumference greater than 88 cm.
  2. Elevated Triglyceride Levels: In both men and women, triglyceride levels equal to or greater than 150 mg/dl.
  3. Low Hdl Cholesterol: For men, a waist circumference greater than 102 cm. For women, a waist circumference greater than 88 cm.
  4. Hypertension: For both men and women, blood pressure equal to or greater than 130/85 mmHg.
  5. Impaired Fasting Glucose: For both men and women, fasting blood glucose levels equal to or greater than 110 mg/dl.

Metabolic syndrome is significantly related to a high danger of evolving type 2 diabetes and cardiovascular diseases and is a prominent cause of morbidity and mortality internationally. Seven out of eight Americans are considered metabolically unhealthy. Even if you don’t think you feel or look metabolically unhealthy, it’s worth spending some time learning about how metabolic health affects the body.

How Does Metabolic Health Affect the Brain?

Unlike other organs, the brain has limited energy reserves and relies on a constant supply of glucose from the bloodstream. Because of this, disruptions in metabolic processes can directly impact brain function. Research on the direct association between metabolism and cognitive function is mixed, but most studies show that metabolic syndrome has a detrimental effect on cognition. 

There are also mixed findings on whether certain cognitive abilities are more affected by metabolic syndrome than others. Some literature finds no tie to certain cognitive functions, while other literature links metabolic syndrome to deficits in memory, visuospatial abilities, executive functioning, processing speed, and overall intellectual functioning.1, 2 Let’s look at the ways an unhealthy metabolism could cause brain fog.

Compromised Blood Flow

Cerebrovascular reactivity is a term used to describe the ability of blood vessels in the brain to respond the changes in blood flow demand, like being able to expand when the brain needs more blood. When your brain is given certain cognitive tasks, neuronal activity in the associated brain region increases, and blood demand increases. Vascular reactivity is key to maintaining regional brain activation by clearing the metabolic waste produced by neuronal activity (e.g., CO2, excess lactate, other metabolites, and heat).3 

People with metabolic syndrome have been found to have impaired cerebrovascular reactivity, higher artery stiffness, and thicker artery walls due to plaque buildup.4, 5, 6 This means that the brain's functioning could be impaired by an inability to receive adequate blood supply, oxygen, and nutrients and get rid of waste.

Lipid Metabolism

In addition to glucose metabolism, dysfunctional lipid metabolism can also drive cognitive decline. Lipids make up about 50% of your brain’s dry weight and are crucial for its function. Dysregulated synthesis and breakdown of lipids in the body can affect the brain by disrupting intestinal microbiota and the gut-brain axis, neuronal signaling, the blood-brain barrier, and mitochondrial function, and increasing oxidative stress and inflammation.7 

Dyslipidemia, characterized by abnormal levels of cholesterol and triglycerides, has been linked to cognitive impairment and dementia. Excessively high levels of certain lipids, particularly LDL cholesterol and triglycerides, can contribute to plaque buildup in the arteries and reduced blood flow to the brain.8

Blood Glucose and Insulin Resistance

Insulin, a hormone produced by the pancreas, plays a crucial role in regulating glucose metabolism. When cells become resistant to insulin, cells’ glucose uptake is impaired. Without enough glucose, brain cells are unable to function optimally, which could lead to cognitive dysfunction and brain fog.

Chronic elevation of blood sugar levels, known as hyperglycemia, has also been associated with cognitive impairment and increased risk of neurodegenerative diseases such as Alzheimer's disease. High levels of blood sugar can lead to inflammation, oxidative stress, and damage to blood vessels, all of which contribute to cognitive decline.2

<p class="pro-tip"><strong>Also Read: </strong><a href="insulin-and-brain-fog">The Impact of Insulin on Brain Fog</a>.</p>

Leverage Your Metabolism to Clear Brain Fog

Runner crossing a bridge.

The good news is that we have some control over our metabolism, more than you might think. Each person’s metabolism is determined by a variety of factors like gender, age, body type, activity level, and diet choices. Our daily habits can shape our metabolism over time and can be powerful tools to improve our metabolic health. Taking care of your metabolic health could improve not only your mental clarity but also a host of other health factors like energy levels, weight, and disease risk factors. Here are some ways to improve your metabolic health, clear brain fog, and improve your overall wellness.


Our food choices are one of the most powerful tools we have to improve our metabolism. Aim to eat a balanced diet that supports stable blood sugar and provides your body with the nutrients it needs. 

Choose to include:

Choose to avoid:

  • Highly processed foods like processed snacks, fast food, and simple carbohydrates.
  • Foods high in sugar, artificial sweeteners, trans fats, and saturated fats.
  • Calorically-dense foods in excess.


Engaging in regular physical activity has numerous benefits for metabolic health and cognitive function. Exercise helps improve insulin sensitivity, promotes glucose uptake into cells, and enhances blood flow to the brain, all of which contribute to reduced brain fog and improved mental clarity.

  • The US Department of Health recommends getting 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic exercise each week. 
  • In comparison, the American Heart Association recommends performing at least 30 minutes of aerobic exercise five to seven days per week.
  • Incorporate weight-bearing exercises to increase muscle mass.
  • Use exercise as a tool to stabilize blood glucose after eating.


In our increasingly sleep-deprived world, it can be difficult to prioritize solid rest. Sleep is intricately connected to many metabolic processes within our body. Sleep deprivation impairs glucose metabolism, increases insulin resistance, and negatively impacts cognitive performance.9 Make sure to get enough deep sleep each night, usually between 7 and 9 hours for adults.


Chronic stress can exacerbate metabolic dysfunction and contribute to cognitive impairment. Find stress-reduction techniques such as mindfulness meditation, deep breathing exercises, or yoga to help you lower cortisol levels when you need to. 

Jumpstart Your Metabolic Health With Signos

Our metabolism affects almost all aspects of how our bodies work, and our metabolic health determines how well our bodies feel and function. With Signos, you’ll learn about your body’s unique response to lifestyle factors like food, exercise, sleep, and stress—factors you can use to shape your metabolic health.

Learn how Signos combines continuous blood glucose data with personalized advice to guide your health journey. Read more about how CGMs can be a tool for managing stress, sleeping better, gaining energy, and losing weight. Take a quick quiz to see if Signos is right for you.

<p class="pro-tip"><strong>Learn More: </strong><a href="12-foods-for-brain-health">12 Healthy Foods for Good Brain Health</a>.</p>

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Topics discussed in this article:


  1. Yates, K. F.; Sweat, V.; Yau, P. L.; Turchiano, M. M.; Convit, A. Impact of Metabolic Syndrome on Cognition and Brain: A Selected Review of the Literature. Arterioscler. Thromb. Vasc. Biol. 2012, 32 (9), 2060–2067.
  2. Koutsonida, M.; Markozannes, G.; Bouras, E.; Aretouli, E.; Tsilidis, K. K. Metabolic Syndrome and Cognition: A Systematic Review across Cognitive Domains and a Bibliometric Analysis. Front. Psychol. 2022, 13.
  3. Drake, C. T.; Iadecola, C. The Role of Neuronal Signaling in Controlling Cerebral Blood Flow. Brain Lang. 2007, 102 (2), 141–152.
  4. Pasha, E. P.; Birdsill, A. C.; Oleson, S.; Haley, A. P.; Tanaka, H. Impacts of Metabolic Syndrome Scores on Cerebrovascular Conductance Are Mediated by Arterial Stiffening. Am. J. Hypertens. 2018, 31 (1), 72–79.
  5. Giannopoulos, S.; Boden-Albala, B.; Choi, J. H.; Carrera, E.; Doyle, M.; Perez, T.; Marshall, R. S. Metabolic Syndrome and Cerebral Vasomotor Reactivity. Eur. J. Neurol. 2010, 17 (12), 1457–1462.
  6. Koivistoinen, T.; Hutri-Kähönen, N.; Juonala, M.; Aatola, H.; Kööbi, T.; Lehtimäki, T.; Viikari, J. S. A.; Raitakari, O. T.; Kähönen, M. Metabolic Syndrome in Childhood and Increased Arterial Stiffness in Adulthood: The Cardiovascular Risk In Young Finns Study. Ann. Med. 2011, 43 (4), 312–319.
  7. Wu, S.; Liu, X.; Yang, H.; Ma, W.; Qin, Z. The Effect of Lipid Metabolism on Age-Associated Cognitive Decline: Lessons Learned from Model Organisms and Human. IBRO Neurosci. Rep. 2023, 15, 165–169.
  8. Reitz, C. Dyslipidemia and the Risk of Alzheimer’s Disease. Curr. Atheroscler. Rep. 2013, 15 (3), 307.
  9. Sharma, S.; Kavuru, M. Sleep and Metabolism: An Overview. Int. J. Endocrinol. 2010, 2010, 270832.

About the author

Alicia Buchter is a content writer for Signos and earned her degree in Biochemistry, Biophysics, and Molecular Biology from Whitman College in Walla Walla, WA.

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Please note: The Signos team is committed to sharing insightful and actionable health articles that are backed by scientific research, supported by expert reviews, and vetted by experienced health editors. The Signos blog is not intended to diagnose, treat, cure or prevent any disease. If you have or suspect you have a medical problem, promptly contact your professional healthcare provider. Read more about our editorial process and content philosophy here.

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