What Is Keto Flu? And How To Avoid It Quickly

keto flu, also known as the carbohydrate flu, is a term coined by keto followers to describe some of the symptoms they experience when they first start the keto diet.

The ketogenic diet has gained popularity as a natural way to lose weight faster and improve health in general.

Although the keto diet is considered safe for most people, it is associated with some nasty side effects.

This article takes a look at what the keto flu is, why it occurs, and how to ease its symptoms.

Did you know?

The keto flu: is your body’s natural response to carbohydrate limitation.

If you’ve embarked on the keto diet, you probably know that a keto diet is high in fat, moderate in protein, and low in carbs – implies burning fatty acids for energy instead of glucose. which comes from sugar and other carbs.

What Is The Keto Flu?

The keto flu is a collection of symptoms that some people experience when they start the keto diet.

These symptoms (of keto flu), which may resemble those of the flu, are caused by the body adapting to a new diet of few carbohydrates.

Cutting back on carbohydrate intake forces your body to burn ketones for energy instead of glucose.

Ketones are byproducts of fat breakdown and become the primary source of fuel while following a ketogenic diet.

Usually, fat is reserved as a secondary fuel source for use when glucose is not available.

This switch to burning fat for energy is named ketosis. It occurs in specific circumstances, including starvation and fasting. [Strong Evidence]

However, ketosis can also be achieved by adopting a low carb diet.

On a ketogenic diet, carbohydrates are generally reduced, to less than 50 grams per day.

Therefore this drastic reduction of carbohydrates. Can cause some symptoms in the body.

16 Symptoms Of Keto Flu

Switching to a very low-carb diet is a major change, and your body may require more time to adjust to this different way of eating.

For some people, this transition period can be particularly difficult.

The symptoms of the keto flu may begin to appear in the first few days after cutting back on carbohydrate.

Symptoms can vary from mild to severe and vary from person to person.

Sometimes, some people can switch to a keto diet without feeling any side effects, others may experience one or more of the following symptoms: [Strong Evidence]

  • Nausea
  • Vomiting
  • Constipation
  • Diarrhoea
  • Headache
  • Irritability
  • Weakness
  • Muscle cramps
  • Dizziness
  • Poor concentration
  • Stomach pain
  • Muscle soreness
  • Difficulty sleeping
  • Sugar cravings

These symptoms are commonly reported by those who have just started the ketogenic diet and can be distressing.

Symptoms usually last about a week, although some people may experience them for a longer period. But don’t worry, there are several ways to reduce these symptoms.

How to Manage Keto Flu Symptoms?

Keto flu can make you feel miserable.

Fortunately, there are several ways to reduce her flu-like symptoms and help your body get through the transition more easily.


Drinking enough water is necessary for good health and can also help reduce symptoms.

A keto diet can cause you to lose water stores quickly, which increases your risk of dehydration.  [Strong Evidence]

That is because glycogen, the stored form of carbohydrates binds to water in the body. When dietary carbohydrates is a reduced, glycogen levels drop, and water is excreted from the body.

Staying hydrated can help relieve symptoms like fatigue and muscle cramps.

Fluid replacement is especially important when you are suffering from diarrhoea associated with the keto flu, which can lead to additional fluid loss. [Strong Evidence]


While exercise is necessary for maintaining good health and controlling body weight, strenuous exercise should avoid when experiencing keto flu symptoms.

Fatigue, muscle cramps, and stomach discomfort are common in the first week on a ketogenic diet, so it may be a good idea to let your body rest.

Activities like intense cycling, running, weight lifting and intense workouts may need to be put on the back burner while your system adjusts to new fuel sources.

While these types of exercise should avoid if you have the keto flu, light activities like walking, yoga, or biking can reduce and improve symptoms.


Replacing dietary electrolytes can help reduce the symptoms of keto flu.

When you follow a ketogenic diet, the levels of insulin, an important hormone that helps the body absorb glucose from the bloodstream, drop.

When insulin levels drop, the kidneys release excess sodium from the body.

Additionally, the keto diet limits many foods high in potassium, including fruits, beans, and starchy vegetables.

Getting adequate amounts of these necessary nutrients is a great way to get through the diet adjustment period.

Salting foods to taste and including potassium-rich, keto-friendly foods like green leafy vegetables and avocados are a great way to make sure you’re maintaining a healthy electrolyte balance.

These foods are also high in magnesium, which can help reduce muscle cramps, sleep problems, and headaches. [Strong Evidence]


Fatigue and irritability are common complaints of people who adjust to a ketogenic diet.

Lack of sleep leads to increased levels of the stress hormone cortisol in the body, which can negatively impact mood and worsen keto flu symptoms. [Strong Evidence]

* If you have trouble falling asleep or staying asleep, try one of the following tips:  

– Reduce your caffeine intake: Caffeine is a stimulant that can negatively impact sleep. If you drink caffeinated drinks, only do so in the morning so that your sleep is not affected.

– Turn off ambient light: Turn off cell phones, computers and TVs in the bedroom to create a dark environment and promote restful sleep.

Take a Bath: Adding Epsom salt or lavender essential oil to your bath is a relaxing way to unwind and get ready for sleep.

– Get up early: Waking up at the same time every day and avoiding sleeping too much can help normalize your sleep patterns and improve sleep quality over time.

Make sure you’re eating enough fat (and carbohydrates)

Transitioning to a very low-carb diet may cause you to want foods that are limited to the ketogenic diet, such as cookies, bread, pasta, and bagels.

However, eating enough fat is necessary to get fuel for the ketogenic diet, which will help reduce cravings and keep you feeling satisfied.

Research confirms that low-carb diets help reduce cravings for sweets and high-carb foods.

Those who struggle to adjust to the ketogenic diet may need to cut out carbs gradually. And not all at once.

Slowly cutting back on carbs, while increasing the fat and protein in your diet, can help make the transition smoother and reduce keto flu symptoms.

How Long Does The Keto Flu Last?

Symptoms of the keto flu usually begin within the first day or two after eliminating carbs. An average person, the keto flu can last for a week or less, but in extreme cases, the keto flu can last up to a month.

However, depending on your genetics, you might never suffer from the keto flu.

Some people are naturally “metabolically flexible,” which means they can easily change their metabolic state without experiencing any health symptoms.

While keto flu symptoms are common reported by those switching to a ketogenic diet.

If you feel particularly unwell and experience symptoms such as prolonged diarrhoea, fever, or vomiting, it is best to contact your doctor for advice to rule out any other cause threatens your health.

Why Do Some People Get The Keto Flu?

While some may experience symptoms of the keto flu for a week or two, others may adapt to the new diet without the unwanted side effects.

The symptoms of keto flu that people experience are related to how their body adjusts to a new source of fuel.

Usually, carbohydrates provide energy to the body in the form of glucose.

When carbohydrates are low, the body burns ketones from fat instead of glucose.

Those who typically consume a lot of carbohydrates, especially refined carbohydrates like pasta, sugary cereals, and sodas, may have more difficulty starting the ketogenic diet.

So, transitioning to a high fat, super low carb diet can be a struggle for some, while others can easily switch between fuel sources with little to no keto flu symptoms.

It is unknown why some people adapt to ketogenic diets easy than others, but did you know that the genetics, electrolyte loss, dehydration, and reduce carb in the body, are the considered among the driving forces behind the keto flu.

Final recommendations: Prevent Keto Flu

Keto flu is a collection of symptoms or signs associated with the body adapting to a ketogenic diet.

Nausea, constipation, headaches, fatigue, and sugar cravings are common in some people who adjust to a diet high in fat and low in carbohydrates.

Staying hydrated, replacing lost electrolytes, getting enough rest, and making sure you’re getting the right amounts of fats and carbohydrates are ways to reduce the symptoms of keto flu.

The symptoms of the keto flu seem very unappealing, so use these suggestions to help prevent them.

Remember, everyone’s body treats the keto diet differently. Consult your doctor or seek nutritional advice and discuss all issues you may have in your diet like – keto flu.

2 réflexions au sujet de “What Is Keto Flu? And How To Avoid It Quickly”

  1. Hi Karima..such a beautiful name! I’m 72 and new to keto ,but need to lose weight very bad because of low thyroid function ( 3 quarters of thyroid removed..On no meds.. dr says I don’t need it but I feel I need t lose weight because I’m considered over weight. I need someone to tell me simple breakfast,Lunch and dinner meals because I can’t focus long enough to prepare these so call easy recipes which require me to go to grocery store for every recipe.I’m on fixed income and don’t eat much ..just tea in morning snack at around 12 and a simple low carb dinner ..maybe a snack later in evening..thats all I require, but keto requires messing with food all day. I don’t feel hungry for all these meal. Do you have any suggestions to help me. Like a simple Keto meal plan..rt now I’m doing it and believe I’m in keto flu with diarrhea..especially after I drink lots of water.I feeling ok, but need some help and encouragement with this..Thank Joinn


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