Keto Flu

Keto Flu- Overview, Symptoms, Remedies And How To Avoid It


If you’re exploring about starting the keto diet, you may have also come across the term called “Keto Flu”. People see it as the most common side effects of the keto diet. Staying in a fat-burning state called ketosis comes with a lot of health benefits.

It’s great for long-term and sustainable weight loss. Body takes one to two weeks to adjust with the new mechanism. When you’re first starting out on keto, you may experience a few days of flu-like symptoms as your body learns to switch over from burning sugar to burning fat.

In general language such symptoms are called as the keto flu. But these symptoms can not be referred to influenza. Rather, they’re a byproduct of the body adjusting to a very-low-carb diet as it depletes stored glucose.

While doing the ketogenic diet body attains ketosis and fats are used as the source of fuel as the liver starts breaking down fat into acids called ketones. For most people, the adjustment period may be mildly unpleasant but not dangerous to their health at all.

What Is Keto Flu?

The keto flu is a temporary group of flu-like symptoms you might experience in the first week or two of starting a keto diet. Keto flu happens when your metabolism tries to adjust to fats instead of carbohydrates.

When you eat carbs, your body burns them as its main source of energy. But if you drastically reduce your carb intake like on a low-carb ketogenic diet your body depletes your glucose stores and starts burning fatty acids for energy instead.

This metabolic switch is what causes keto flu your body is still looking for carbs because it hasn’t yet figured out how to burn fat for fuel efficiently. Keto flu passes once your body gets out of carbohydrate withdrawal and adapts to burning fat for fuel.

How Does Keto Flu Feel?

The name “keto flu” is quite exaggerated with something negative. People quite mistaken it with an influenza virus.

However in the initial phase symptoms like headaches, dizziness, fatigue, cramps, and muscle pain might happen. But this is just an indication that body is entering into ketosis.

If you experience fever and body ache, it’s best to consult with a doctor, as the cause is likely unrelated to a ketogenic diet. The symptoms of keto flu varies from person to person, but there are some common ones to watch for.


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Symptoms Of Keto Flu

Generally body takes 7 to 10 days to attain ketosis, and symptoms usually begin within the first day or two of carbohydrate restriction.

In general, the symptoms of keto flu are:

Sugar cravings
Brain fog
Poor focus and concentration
Stomach pains
Muscle soreness

But not to worry, one might experience one or two of these symptoms or none at all. The severity and length of the symptoms will be different depending on the person.

Don’t let the long list scare you! following are the reasons why there isn’t a need to worry about these:

You likely will not get all these keto flu symptoms. Everyone reacts differently.
You can avoid the keto flu! Read on to find out how.
Why Keto Flu Affects Everyone Differently

The main reason behind Keto Flu being different in terms of affecting people is nothing but just metabolic flexibility. Now, this is the capacity for the organism to adapt fuel oxidation to fuel availability.

In other words, metabolic flexibility is how well you can adapt to using different fuel sources like carbs, fats, protein, and ketones. There are many factors that determine metabolic flexibility, but we will stick with two of the most well-known: genetics and lifestyle.

Looking At Genetics

From a genetic perspective, certain people are less metabolically flexible because they have genetic variations that make it more difficult for them to adapt to the ketogenic diet.

In contrast, those who are quick keto-adapters may be gifted with genes that enhance their ability to switch between fuel sources more efficiently.

Looking At Lifestyle

Lifestyle is a major factor as well. If you are in a practice of eating a diet high in refined sugar and processed foods, you’re more likely to experience severe keto flu symptoms.

On the contrary, If your diet is low on processed sugars and starches, you may only experience mild keto flu symptoms or none at all.

A similar trend emerges with exercise. One should make exercise a part of their life will be more metabolically flexible than those who are sedentary.

Causes Of Keto Flu

Here are several primary keto flu causes:

  • Electrolyte Imbalance


It is the primary cause of the keto flu. Minerals are electrolytes that aid numerous functions when dissolved in water and are necessary for critical body functions.

Regulating Water In Your Body
Balancing PH Levels
Moving Nutrients Into Cells
Moving Waste Out Of Cells
Making Sure Your Nerves, Muscles, and Brain Work Properly.

When you restrict carbohydrates, your body produces less insulin, causing your kidneys to flush out excess water and sodium. Our kidneys will also release extra potassium, calcium, and magnesium in order to maintain balance between sodium and potassium.

You might experience keto flu due the deficiency of sodium, potassium, calcium, and magnesium in your body.

Sugar Withdrawal

Studies show that sugar is highly addictive. If you are into consuming a lot of sugar then switching to a keto diet can come as a shock and lead to withdrawal symptoms.

These symptoms include:

Cognitive issues


So, it is great to switch to a ketogenic lifestyle. It is better to consume healthy fats, low carb vegetables, unprocessed meats, eggs and other whole foods instead of processed and packaged foods.

However, just like other diets, you can do it incorrectly. If meat, cheese, keto desserts, and low carb bread are your go to foods then you may end up with deficiencies in vitamins and other micronutrients.


When you derive maximum percentage of energy from carbohydrates, this leads to increased storage of glycogen in the liver, where they are bound to water molecules and resulting in water retention. Eating low carb depletes this glycogen, which allows you to burn fat but it also means you are storing less water, making it easier to get dehydrated.

However, replenishing electrolytes is as important as drinking adequate amount of water. Because if you will dilute the concentration of electrolytes in your body even further and possibly make your keto flu worse. This is why it’s important to address both together.

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How Long Does It Last?

Usually the keto flu lasts for about 7 to 10 days. It usually peaks around 3-4 days in. Symptoms usually occur within the first day or two of starting your new diet. How long the keto flu lasts varies from person to person of course.

Some people don’t get the flu at all, while others could experience it for close to a week. However the symptoms do not last for more than a week and goes away once you adapt to it.

Keto Flu isn’t dangerous and it only lasts during your transition into ketosis before disappearing for good. You may experience a few signs like fatigue, trouble focusing, sugar cravings, and headaches.

If it turns up over and over again, you might be going in and out of ketosis. Check your diet for hidden carbs and make sure to track your macros especially during the first month or so.


Following steps will lessen keto flu at least lessen the symptoms.

Always drink when you feel thirsty, make sure you drink adequate amount of water.
Drink maximum water during the day so your sleep does not get disturbed due to a trip to the bathroom.
Increasing your sodium intake. This will help counteract the water loss that happens when starting a keto diet and replenish sodium.
Supplement with magnesium with rich food like avocados, pumpkin seeds, cooked spinach, halibut, cashews, salmon, macadamia nuts, and dark chocolate.
Eat potassium-rich keto foods. Potassium is an important unnoticed key mineral.
Eat calcium-rich keto foods like Broccoli, leafy greens, chia seeds, sardines, and salmon are all packed with calcium.
Taking an electrolyte supplement will help replenish your levels faster as compared to foods.
Getting light exercise 2-3 times per week can burn through your carb stores faster and increase your metabolic flexibility, which helps relieve the symptoms more quickly.
Make sure the calories you used to get from carbs are partially replaced by eating plenty of keto-friendly fats.

In A Nutshell

Keto flu-like symptoms will subside once your body adapts to it. Give your body time. Once the transition phase is over, you can experience increased energy, weight loss, mental clarity, and all the other benefits of ketosis.

Get yourself started today with Customized Diet Plans and Stay tuned for more such ketogenic transformation stories, health content, and recipes! Also, don’t forget to follow us on Instagram for the daily dose of the Keto Lifestyle!


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