Mental clarity is one of the benefits of being in ketosis so why are people talking about brain fog on a Keto diet. When your body starts producing ketones in sufficient amount your brain starts functioning better, it’s like kicking it in higher gear.

There are several possible reasons for brain fog also called mental fatigue. One of them is also insulin resistance. As you can see they are not all related to your diet. We will be discussing brain fog caused by low levels of glucose in your blood.

Your brain functions on two different fuel types. The first one is glucose and the second one are ketones. If you have hypoglycemia or you haven’t eaten enough carbohydrates for a while you glucose levels drop in your body.

When this happens, your brain is running out of fuel and kicks in a fuel saving mode. Unless your replenish your glucose or your body starts producing ketones in satisfactory amount your brain will feel the lack of energy and most people will suffer from some type of brain fatigue. Some people also experience some sort of keto flu.

As ketones are a better and more stable type of fuel for your brain many people experience and improvement of mental clarity and performance when they are fully keto adapted. To clarify being in ketosis and being fully keto adapted is not the same thing. Being in ketosis means that your body increased production of ketones, being fully keto adapted brings also some other changes in your body that support this type of regime.

It takes about one month to become fully keto adapted while getting into ketosis could be done in as little as 24 hours.

The effects of brain fog disappear somewhere in between when you enter ketosis and when you become fully keto adapted. For some people it can be even faster as everyone reacts differently.

Even if your body increases production of ketones while it enters the state of ketosis it is usually still not enough to support the needs of your brain 100%, so you still experience some effects of brain fog.

Look at it as a sort of a roller coaster. When you remove carbs from your diet, your brain still depends on glucose, this is the downhill part of a roller coaster. When you reach the bottom your body has used all of glucose reserves and starts to produce ketones. This is the uphill part of the roller coaster ride. Your production of ketones is going up and levels are increasing every day and every day you feel better. However until you reach the top you will not have that mental clarity and you will still have some brain fatigue.

If you are experiencing that your brain fog is not going anywhere, or your symptoms are more severe you might have some other issues and you should consult with a medical professional.

Maybe you are low on electrolytes or have some other type of mineral deficiency. What you need to do in a situation like this is to get examined by a doctor, you don’t want to risk anything.

If the doctor says everything is ok you can continue but this time you need to take care of your nutrition. It is not just calories in and calories out, it’s all about quality and by quality I mean nutrients that your body needs to work properly.

Even if you don’t have severe issues it will help and speed up your transition into ketosis if you have a well balanced diet. I personally believe that eating healthy is fundamental to a healthy life and definately to enter ketosis faster.

Mindfulness Law of attraction
Cognitive effects of ketosis

What Are the Cognitive Effects of Ketosis?

Even dough no prospective studies of developmental or behavioral outcomes have been performed so far, anecdotal evidence and parental report measures have indicated that children treated with the ketogenic diet  show increased alertness and better cognitive functioning, as well as improved behaviour. You car read more about it here.

How to get rid of Brain fog

From a scientific perspective brain fog is caused by depressed GABA and elevated ammonia. It is not uncommon and it happens to most of us during our life. It feels like there is a layer between you and the world and everything seem a little slower. Your performance is not optimal and you don’t feel energetic.

Ketosis increases brain glutamine syntheses, and brain glutamine syntheses reduces extra ammonia.

Ketosis also increases production of GABA. GABA is a neurotransmitter that acts as a counterbalance to glutamate. Our brain needs both but too much glutamate can cause neuronal degeneration.

Increased euphoria

Ketones can induce feelings of euphoria in some people. The opposite reaction to a state of euphoria is depression which is a known factor to decrease mental performance but on the other hand to much of euphoria can have the same effect.

There are also different types of supplements that you can take to alleviate brain fog symptoms. They can either speed up the process of getting over the symptoms or even make them go away completely.

Studies about effects of ketosis

Type 1 diabetics who experience reduced cognitive function because of low blood sugar see those deficits erased by increasing BHB through dietary medium chain triglycerides (the same fats found in coconut oil). You can find the study here.

In memory impaired adults, some with Alzheimer’s, BHB improved cognition. Scores improved in (rough) parallel with rising ketones. You can find the study here.

A very low-carb diet improved memory in older adults. Again, ketones tracked with improvements. You can find the study here.

A ketone-elevating agent (purified medium chain triglycerides) improved cognition in patients with mild to moderate Alzheimer’s. You can find the study here.

State of mild ketosis

Even a state of mild ketosis can bring some great benefits and it is much easier to get into it than you think. If you had an early dinner or dinner without any carbs your body will already be in a state of mild ketosis when you wake up in the morning.

What I like to do is that I eat only eggs for breakfast and induce a mild ketosis this way. Some people skip breakfast, but I am addicted to my coffee and I don’t like to drink it on an empty stomach as I had some issues because of it.

You can even get in state of ketosis in one day. This is however a more extreme approach.

Keto meal for ketosis

Best ways to induce mild ketosis

A short fast: Taking a short fast has so many benefits and ketosis is just one of them. A fast can be anything from 12 to 48 hours. You can do longer even fasts but after a few days if not earlier you will definately be in full state of ketosis.

No carb dinner or skip it completely: As already mentioned if you don’t overeat on carbs in the evening you will wake up in mild ketosis already. Now if you eat zero carbs or even skip dinner entirely this will work even better. One other option is also if you move your dinner to an earlier time frame, I however prefer to either skip it or maybe just have a salad with some eggs.

Eat MCT’s: MCT oils are known to increase the creation of ketones. You can either buy a MCT oil which is almost 100% MCT or you can start adding the good old coconut oil to your diet as about 55-60% of the fats in coconut oil are MCT oils and even the MCT oil that you can buy is derived from coconut oil.

Is ketosis dangerous?

There are many myths about keto and ketosis and people get afraid that it is not healthy or that it is unnatural. Some people think that carbs are essential for health, some that they will get a heart attack others again are worried about their physical performance. The topic is so broad that I  wrote an extensive article where I bust 12 common myths about ketosis.

To wrap it up

As I write only about things I tried myself and can personally testify that whenever I am in state of ketosis is generally feel more energetic and have better mental clarity. I also think that I have a problem with digesting carbs as I get really tired immediately after eating them which I fight with eating digestive enzymes that help me a lot.

I can eat loads of fat and will not feel any problems, but as soon as I eat a lot of carbs it makes me sleepy. It might be that just this fact gives me all the additional energy but I definitely feel better on low carbs, once I am over the initial accommodation period that is.

I firmly believe that people have different adaptations towards digesting different types of foods. Some people cannot eat fat, some people like myself are having difficulties digesting carbs, and some have problems with high fibre foods. There was even a study that proved that insulin responded differently to same types and amounts of food in different people. Some people had a higher insulin response from eating a piece of bread as compared to others eating two scoops of ice cream. This just shows us that we must find what fits best to us. You have to be in tune with yourself and listen to your body.

So why not give it a go and see if ketogenic diet is for you. You can only benefit even if it turns out it is not for you.


I am happy father of two and a health and fitness enthusiast.

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