Keto Flu Symptoms: How Long Does It Last and Its Remedies

A ketogenic diet or better known as keto, is the modern way of losing fat that many people are adopting. However, the enthusiasm and immediate change of diet from a general all carbohydrates to all fats can have various effects on your body.

Keto flu is one of them. It is a mild and symptomatic onset of a condition that has your regular flu-like symptoms- Only that it is not your regular flu and has much to do with your body entering a ketosis metabolic state.

If you’re experiencing keto flu symptoms and you’ve only begun your keto diet, do not despair nor feel let down. It is short term, and with the proper care and remedies, it will be gone in no time.


Keto flu is like a withdrawal symptom. Why the withdrawal? Because your body is normally used to a particular metabolic pathway where it is habitual of breaking down carbohydrates for the majority of the energy obtained since they’re easiest to break as compared to proteins and fats. Fats are harder to break down and require more energy to that.

Whether it’s the withdrawal-like effect or a mild reaction to the changes your body goes through when it switches from breaking down glucose to fat. That is something no one has figured out yet.

What is Keto Flu?

Keto Flu itself is a collection of symptoms similar to your regular flu that has an onset of about two to seven days after one begins keto diet. Symptoms vary from person to person, but the most common reported seem to be headache, dizziness, fatigue, lethargy, nausea, and constipation. 

Some of the symptoms are not recognized by science. That means that a few of them cannot be said to have a strong scientific relation to how ketogenic diet affects the body. No research papers describe this phenomenon; however, a lot of personal medical and lifestyle blogs and gurus cannot talk enough about it.

It is difficult to pinpoint the source of the symptom precisely and to relate each of it to the mechanisms of a ketogenic diet. However, it is imperative that sudden and impulsive changes in diet can alter the metabolic system, leading to a couple of varying effects- which is what apparently happens in keto flu. 

However, not all of the keto flu symptoms associated or described by people are diagnostic symptoms. In healthcare forums and personal training blogs, people have reported similar symptoms when they cut back on processed food or immediately switch to an elimination diet. 

Keto flu is also known as keto induction, as the majority of the people associated with the onset of keto flu as an indicative factor that your body has successfully switched to ketogenesis. Some even consider this an important part of the keto diet since a lot of new people find it hard to figure out whether ketosis has begun in their bodies or not.

What are the symptoms of keto flu?

Like we mentioned earlier that keto flu symptoms are similar to your regular flu. There are other symptoms that people report as well but are not officially recognized as an indication of keto flu.

The onset of symptoms is mild and begin a few days after you start on the keto diet. It lasts only a few days to weeks and can range from mild to moderate in severity varying from person to person.

According to a scientific profile of the keto diet, keto flu comprises of the following symptoms.

  • Nausea
  • Vomiting
  • Fatigue
  • Headache
  • Dizziness
  • Sleeplessness
  • Lethargy
  • Fatigue
  • Constipation 

Other widespread symptoms reported by researchers are.

  • Muscle cramps
  • Diarrhea
  • Weakness
  • Bad breath
  • Rash
  • Lack of focus
  • Sugar cravings

Additionally, a few other symptoms that are short term symptoms and predictable from a scientific point of view when taking a low carbohydrate diet are.

  • Low blood sugar episodes 
  • Hypoglycemia
  • Dehydration
  • Low energy

Bad breath is a symptom that is quite prevalent in people who are on a keto diet. It is not a major symptom of keto flu, though. When a body is actively functioning on a ketosis metabolic process, the liver is pushed to produce a ketone called acetone. This acetone molecule easily enters the bloodstream, circulates the body and passes into the lungs on contact, and becomes part of the exhaled gases during breathing. Hence the distinct smell.

It is important to remember that no matter how indicative the symptoms appear to be, it should not last more than a few weeks. If they do so, you should see a doctor immediately.

Despite the keto flu fiasco and people worrying about how dangerous it could be, it really is not. In fact, a ketogenic diet is often prescribed and endorsed by medical professionals in cases where obesity negatively affects a medical condition or disease.

It is beneficial for people suffering from endocrine diseases such as obesity, thyroid enlargement, and diabetes. It is also helpful with certain neurological diseases like epilepsy.

What causes keto flu?

We’ve explained above briefly about how and why a ketogenic diet approved by health professionals would cause keto flu or induction. The most accurate yet easy way to understand the cause of keto flu is to understand that your average diet consists of large portions of carbohydrates, fats, and proteins.

Carbohydrates are your body’s favorite thing to break down to obtain energy. They’re easier to break, are heavily concentrated with glucose, which is more than enough for your body to run on as fuel. The fat you eat is stored in the form of fat deposits, so your body never really bothers to break down fat.

These fat deposits make you gain weight and lead you on a path to obesity. When you start on a ketogenic diet, you reduce your carbohydrate from minimal to absolutely none. This way, you’re forcing your body to break down your fats stored and burn them to provide energy for the body to function.

Switching from a high carb diet to a high-fat diet lowers the insulin levels in your body. Insulin is a hormone that breaks down sugar. This low insulin level forces your liver to convert fats into ketones, which is an alternate source of energy for the cells of your body.

When your body completely begins to utilize ketone as a source of energy unit instead of glucose, your body has officially entered the state of ketosis. Hence, the ketogenic diet.

While this may sound simple enough, there are cells in your body that take more time to adapt to ketones as an energy source, like the brain, for instance. Another adaptive process is your body excreting more sodium in the urine, which takes up more water. This is why frequent urge to urinate is also a common sign at the beginning of a keto diet.

While this may work for may people in the form of rapid weight loss, the loss of sodium and water can lead to dehydration and other flu-like symptoms. The adaptive time taken for the body cells can also be taken into account since an immediate switch in the diet can induce flu-like symptoms more effectively.

However, the symptoms are mild and quite very bearable. They’re a nuisance for people who have just begun the keto diet, and it seems to affect their initial progress to adhere to the diet. The symptoms can be relieved with the right care and education.

What are the possible cure or remedies?

While the flu can make you feel very inconvenienced, there are always ways to deal with it. A few important remedies are as follows. 

1. Hydration and salt intake

Whether its health, lifestyle or skincare, it is emphasized countless times of how important drinking water is. For keto flu remedy, drinking enough water is the pro tip anyone can offer to help reduce symptoms. Healthy water intake levels can alleviate most of the stated symptoms like dehydration, headache, dizziness, and nausea. 

Keto diet itself is enough to cause more water loss, increasing the risks of dehydration, which can further lead to muscle cramps and fatigue or constipation. Sodium intake is also crucial since it is practically flushed out in the urine.

Adding a little amount of table salt in your water can do wonders for you during keto flu, including fighting off electrolyte imbalance incase of ket flu induced diarrhea. 

2. Avoid intense workout 

Yes. Exercise or working out is great for losing weight and staying healthy and active. But during a keto flu remedy, it is advised to avoid any strenuous exercise strictly. If one is already experiencing muscle cramps, fatigue, and upset stomach, one should avoid adding to the discomfort.

The first week of the ketogenic diet is enough of a burden on your body as it is. Adding to the workload can have wrong impacts and only increase the intensity of the keto flu symptoms. General exercises like walking, light jogging, or biking may help you feel better and even improve the symptoms.

3. Slow transitions

People begin the ketogenic diet with high morales and motivation. They are met with discomfort and a keto flu right at the beginning, which can be disappointing and lower dedication to the diet. This is why many nutritionists and lifestyle gurus advise beginning with a transitioning phase to not only get used to the idea of a high-fat diet but to also allow your body to adapt to it. 

Start by balancing out your carbohydrates with the fats and then slowly decreasing the portions till you’re down to minimal carbohydrate intake. It is also advisable to keep a small portion of carbohydrates as part of your ketogenic diet. It reduces cravings, and it keeps the symptoms and even many cases, the onset of keto flu symptoms at bay.

4. Intake heavy fats

Sometimes, people switch to ketogenic diets, eat a high carb diet, and yet cannot achieve the ketosis state required for it to begin working. They experience the keto flu symptoms, yet they remain dangling between ketosis and glucogenesis.

As a remedy, they are advised to eat high content fat. You can get MCT oils, butter, fat additives and use them in your diet to achieve the fat level to reach the ketosis that you require. Organic high fat content food items allow your body to adapt to ketosis hassle-free.

4. Fiber intake

Whether its constipation of a keto flu induced diarrhea, both are perhaps the harshest of the symptoms of the keto flu. Many people who begin a keto diet have a hard time balancing all the nutrients and requirements os the body. The least considered are the fibers. 

As keto flu remedy to relieve constipation, drinking loads of water is not enough, nor is salt or electrolyte replacement in case of diarrhea. Fiber is necessary to keep your stomach balanced and happy. There are plenty of low carb vegetables out there like avocado, broccoli, or cauliflower than one can consume.

4. Plenty of rest 

If it’s one thing keto diet affects anyone in the first few days to weeks, it’s the sleep cycle. We mentioned earlier how the brain cells are one of the last cells in the body to adapt to the ketosis state, which is why lack of sleep is keto flu symptom as well.

The only remedy is to nap whenever you feel like it to catch up on your sleep. Go to bed early to help yourself fall asleep, or in case you cannot sleep, rest. It is equally important to do that so you may lessen the lack of sleep induced symptoms like irritability or lack of concentration.

What should I avoid?

In order to avoid the signs of keto flu in the first place, here are a few tips and tricks.

  1. Slow and steady. Remember that the ketogenic diet affects everyone differently, and so do the signs of keto flu. The best agreeable way to avoid that is to begin slow and steady. Start with a medium carb diet and work your way down there.
  2. Don’t forget your vitamins and minerals. These are small amounts of compounds that are required by your body on a daily basis. These play a vital role in regulating your metabolic processes and hormones. Since the keto diet is all about switching your metabolic process, vitamins are a necessity. Try using mineral-based supplements as well.
  3. Eat more. That’s right. You’re trying to lose weight but eating more is the key here. As absurd as it sounds, burning fats is a tedious procedure for your body, and it needs a constant supply of energy to do so. If you’ve reduced your carbohydrates, it is important that your diet is high in fats, otherwise, in case of low carb and low-fat diet, you will risk the success of the keto diet. It will also make you hungry, lethargic, and irritable.

How long does Keto flu last, and why?

People adapt to ketogenic diets differently, at their own pace. Some jump right into it and do not show signs of keto flu at any time of the early days. While for another following suit can experience a full-blown keto flu symptoms. 

It is also generally believed that a person who has been eating high carb foods for most of his life is more prone to signs keto flu as compared to someone who has been consuming a balanced diet. The onset and the keto flu time period varies from a few days to a few weeks, three at the most. 

The science behind how long keto flu symptoms last remain dependent on the time for a body to adapt to ketosis. Many other secondary factors come into play as well, such as type of food, region, metabolic rates, genes, dehydration, withdrawal, etc.

The good news is that no matter how long it takes, your body does eventually adapt to ketosis since, even in the normal state, ketosis occurs all the time, only at a smaller scale. The signs of keto flu eventually start to go away, allowing you to enjoy your new diet with a renewed dedication.

The bottom line

Signs of keto flu are nothing to worry about despite the alarming symptoms. It is only natural and very short term. However, the ketogenic diet itself is not for everyone despite being helpful for a vast majority. 

If you’re pregnant or breastfeeding, then the ketogenic diet is not appropriate for you. If you’re in your late teens, it is not advisable to pursue it unless under medical supervision. It is also not suitable for people with health conditions such as kidney or liver diseases. It is also not appropriate for people who are sensitive to dietary cholesterol.

If you’re a healthy individual that does not fall in the above-stated categories, you do not have to worry about how long keto symptoms last. Just follow the remedies and remain knowledgeable about your intake in order for the keto diet to work in your favor.