Can Keto Cause Brain Fog? Here’s What You Need to Know

The keto diet has become increasingly popular in recent years as a way to lose weight and improve overall health. But can keto cause brain fog? Brain fog is characterized by confusion, forgetfulness, difficulty concentrating or focusing on tasks, mental fatigue, and an overall feeling of being out of it.

While some research suggests that certain aspects of the low-carbohydrate ketogenic diet may contribute to improved cognitive performance over time, there are also potential risks associated with it that could lead to increased feelings of brain fog. In this article, we will explore how different components of the keto diet affect our brains and what strategies can be used to reduce or avoid any negative effects. So let’s answer: can keto cause brain fog?

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Can Keto Cause Brain Fog?

Can keto cause brain fog? For us to answer this question, let us learn what the keto diet is and what its positive and negative effects are.

What Is the Keto Diet?

The keto diet, also known as the ketogenic diet, is a high-fat, low-carbohydrate eating plan that has been used for centuries to treat certain medical conditions. It involves drastically reducing carbohydrate intake and replacing it with fat.

This reduction in carbs puts your body into a metabolic state called ketosis. Ketosis is when your body burns fat instead of glucose (sugar) for energy.

How Does The Keto Diet Work?

When you follow a traditional Western diet consisting mostly of processed carbohydrates such as bread and pasta, your body breaks down these starches into glucose which it uses for energy throughout the day.

When you switch to a low-carb, high-fat approach like the keto diet, your body enters into what’s known as “ketosis” where it begins burning stored fat instead of glucose for fuel. This leads to rapid weight loss over time without feeling deprived of fewer calories, because fats are more satiating than carbs so hunger isn’t an issue.

Benefits of the Keto Diet

The primary benefit of following a keto diet is weight loss due to reduced calorie intake from carbohydrates being replaced by fats and proteins.

Additionally, research suggests that following this type of eating plan may improve blood sugar control and reduce inflammation in people with diabetes or prediabetes.

Other potential benefits include improved mental clarity, increased energy levels, better sleep quality, and improved moods due to an increase in healthy fats such as omega-3 fatty acids found in fish oil supplements or foods like salmon or mackerel.

What Is Keto Fog?

Keto Fog is a term used to describe the mental confusion and lack of clarity that can occur when following a ketogenic diet. This foggy feeling can be frustrating, but there are ways to reduce its effects and improve your overall brain performance.

Keto fog is caused by the body transitioning from using glucose as its primary source of fuel to relying on fats for energy production. When this happens, it causes an imbalance in electrolytes such as sodium, potassium, magnesium, and calcium which can cause confusion or difficulty concentrating.

Additionally, since keto diets tend to be low in carbs they also tend to be low in fiber which may lead to constipation. This is another factor that could contribute to cognitive impairment.

Can keto cause brain fog? Yes, especially if a person does not ease into their diet well. Let’s look at keto fog more closely in the next section.

A Closer Look at Keto Fog

Keto fog is a common phenomenon experienced by those on the ketogenic diet. It’s characterized by mental fatigue, confusion, and difficulty concentrating.

The exact cause of this condition is still unknown, but there are several theories as to why it occurs.

Low Blood Sugar Levels

One theory suggests that low blood sugar levels may be responsible for keto fog. When following a strict ketogenic diet, your body enters a state of nutritional ketosis in which it burns fat instead of carbohydrates for energy.

This can lead to lower-than-normal blood sugar levels which can affect cognitive function and cause brain fog-like symptoms such as confusion and lack of focus.


Another possible explanation for keto fog is dehydration due to increased urination caused by the high-fat content in the diet.

When you’re not getting enough fluids, your body becomes dehydrated which can lead to headaches, dizziness, and other cognitive issues like difficulty focusing or thinking clearly – all signs of “keto fog.”

To prevent this from happening make sure you drink plenty of water throughout the day when following a low-carb, high-fat eating plan.

Nutrient Deficiencies

Nutrient deficiencies may also contribute to brain fog on the ketogenic diet since certain vitamins and minerals are essential for proper cognitive functioning such as B vitamins (thiamine), vitamin D3, omega-3 fatty acids (EPA & DHA), magnesium, zinc, and iron.

If any one or more of these nutrients are lacking in your diet then it could result in decreased mental clarity and concentration leading to what we know as “keto fog.”

To ensure adequate intake try adding foods rich in these nutrients into your meals or taking supplements if needed.

Keto fog typically lasts for 1-2 weeks. However, some people may experience it for longer periods.

It is important to note that this symptom usually subsides as your body adjusts to the new dietary changes and your brain begins using fat instead of glucose as its primary fuel source. Additionally, taking supplements such as omega-3 fatty acids and magnesium can help reduce the duration of keto fog.

can keto cause brain fog


How to Manage Keto Fog

Keto fog, also known as “brain fog” or “keto flu” is a common side effect of the ketogenic diet. It is characterized by difficulty concentrating, confusion, and forgetfulness. Fortunately, several natural remedies can help manage this condition and improve overall brain performance.

Get Enough Sleep

Getting enough sleep is essential for managing keto fog. Aim to get 7-9 hours of quality sleep each night to ensure your body has time to rest and repair itself.

Additionally, avoid caffeine late in the day as it can interfere with your ability to fall asleep at night.

Increase Your Intake of Omega-3 Fatty Acids

Omega-3 fatty acids are important for cognitive function and have been shown to reduce inflammation in the brain which may help improve mental clarity during periods of keto fog. Try adding more omega-3-rich foods such as salmon, sardines, walnuts, or flaxseeds into your diet regularly, or consider taking an omega-3 supplement if needed.

Exercise Regularly

Regular exercise helps increase blood flow throughout the body including the brain. This can help improve cognitive function and reduce symptoms associated with keto fog like fatigue and irritability.

Aim for 30 minutes of moderate physical activity most days of the week such as walking or swimming for best results but any amount will be beneficial!

Reduce Stress Levels

Stress can cause a decrease in focus and concentration so it’s important to find ways to relax when dealing with keto fog symptoms like headaches or mood swings.

Consider activities like yoga, meditation, or deep breathing exercises that can help you stay calm while still getting some physical activity in too!


Can keto cause brain fog? Yes, the keto diet can cause a decline in mental clarity. However, this side effect is usually temporary and can be avoided or reduced by following a few simple strategies such as eating nutrient-dense foods, exercising regularly, or reducing stress levels.

With proper planning and care, you can enjoy the many benefits of the keto diet without experiencing any negative effects like brain fog. If you are still concerned about whether or not keto is right for you, it is best to consult with your doctor before making any changes to your diet.

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