What Is Keto Flu And How To Fight It?

What Is Keto Flu And How To Fight It?

Now we all know what the different types of weight-loss diets are and that the keto diet has been gaining popularity a lot from the past few years. But did you know that you are prone to getting the Keto flu when you follow the keto diet? So when you want to get into the diet, make sure you know everything about it, like the flu.

Keto flu is basically a collection of symptoms that some people experience when they start the keto diet for the first time. These symptoms feel similar to the flu which are caused by the body trying to adapt to a new diet that consists of very little carbohydrates.

When you reduce your carb intake it forces your body to burn ketones for energy instead of glucose. During the ketogenic diet, ketones, the byproducts of fat breakdown, become the main fuel or the main energy source for the body.

Normally, when glucose is not available the reserved fat acts as a secondary fuel source. This switch of burning fat for energy is called ketosis. This condition basically occurs during specific circumstances that include starvation and fasting.

Nevertheless, ketosis can also be reached by adopting a very low-carb diet. Carbohydrate intake is typically reduced to under 50 grams per day in a ketogenic diet.

This sudden and drastic reduction can come as a shock to the body and may cause withdrawal-like symptoms which is similar to the conditions while weaning off an addictive substance like caffeine.

Symptoms Of Keto Flu

When the body switches to a very low-carb diet it goes under a major change and definitely requires time to adapt to this new way of eating or diet. For some people, this transition period can be quite difficult.

Symptoms Of Keto Flu - Headache

The symptoms of the keto flu may start to pop up within the first few days of cutting back on the carbs intake. These symptoms vary from individual to individual and can range from mild to severe.

While for some people the transition to a ketogenic diet happens without any side effects others may experience one or more of the following symptoms:

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

These symptoms are generally reported by those who have just begun the ketogenic diet and can be really distressing. Some people may experience these symptoms for a longer period but typically it lasts about a week. While these side effects may encourage some dieters to keep themselves away from continuing keto diet, certainly there are ways to reduce them.

Why do people get Keto Flu?

Generally, different people adapt to ketogenic diets differently. While some people may experience weeks of keto-flu symptoms, others may simply adjust to the new diet with literally no side effects. The symptoms that occur are basically tied to how people’s bodies adjust to the new fuel source.

In general conditions, carbs provide the body with energy in the form of glucose while in the absence of carbs or when the carbs intake is substantially reduced, the body burns ketones from fat instead of glucose.

People who are typically habituated to consume a lot of carbs, especially refined carbs like pasta, soda and sugary cereals may find it more difficult while they begin the ketogenic diet.

Consequently, the transition to high-fat and very low-carb diet may be a difficult task for some while others may be able to switch between fuel sources easily with little to no keto-flu symptoms.

The reason why some people are able to adapt to ketogenic diets more easily than others is still unknown, but genetics, electrolyte loss, carbohydrate withdrawal are believed to be few of the main driving forces behind the keto flu.

How Long The Keto-flu Symptoms Last?

Keto Flu Lasts For A Week

Fortunately, the unpleasant symptoms of the keto flu only last for about a week for most people. Nevertheless, some people may experience more difficulty in adapting to this low-carb and high-fat diet.

For these people, symptoms may last for several weeks. But these symptoms will definitely decrease as your body get used to transforming ketones into energy.

While keto-flu symptoms are basically reported by those shifting to a ketogenic diet but in case you are feeling particularly unwell and are feeling particularly unwell with prolonged symptoms of diarrhoea, fever or vomiting, it’s better that you immediately consult a doctor to rule out other causes.

People Who Should Avoid Ketogenic Diets

Even though the ketogenic diet is helpful for many people, it is not suitable for everyone. The ketogenic diet may not be appropriate for pregnant, breastfeeding women, teens and children unless and until you are therapeutically advised by your medical supervision. 

In addition to the above, this diet should be avoided by people with certain health conditions like kidney disease, pancreatic conditions or liver disease. Also, people who have diabetes and are interested in following a ketogenic meal plan should primarily consult their doctor to determine whether the keto is safe and suitable for their specific needs.

This diet is also not suitable for people who are hypersensitive to dietary cholesterol and such population account for around one-quarter of the world’s population. 

Signs Of Ketosis

Following are some symptoms that may help a person to determine whether the ketogenic diet is working for them or not:

Increased Ketones

When you have ketones in the blood that is probably the most definitive sign that the individual is in the ketosis process. More often doctors may also use urine samples and breath tests to check for ketone levels but these are considered less reliable in comparison to the blood samples.

Weight Loss

Such kind of very low carbohydrate diet is quite effective for weight loss as suggested by some of the researchers. This is the reason why some people expect to lose weight when in ketosis. Individuals on a ketogenic diet may notice weight loss in the first few days but this is generally a reduction in the water weight and the actual fat loss may not occur for several weeks.

Signs Of Ketosis - Weight Loss


As a side effect of water loss, ketosis may cause some people to feel thirstier than usual. Moreover, high levels of ketones and an electrolyte imbalance can also lead to dehydration and can cause complications.

Studies show that athletes may have a higher risk of kidney stones which is simply a complication of dehydration and is considered as a side effect of ketosis.

Bad Breath

Generally, ketones leave the body through breath and urine thus, people on the keto diet or those around them may notice that the breath smells or fruity. Ketones like acetone, benzophenone and acetophenone are usually responsible for the odour and may contribute to bad breath.

Improved Focus And Concentration

At first, the ketogenic diet may cause headaches and concentration difficulties nevertheless, these symptoms would fade over time. People who tend to follow a long-term ketogenic diet often report better clarity and focus. Also, researchers have proved that the people showed greater alertness in some cognitive tests.

Fat Phobia is quite common among the people with the keto diet. It’s been a decade since we are misinformed regarding fat being unhealthy. But in the case of low-carb ketogenic eating fat consumption is utmost important otherwise your body will think it is starving which will make you feel tired, hungry and miserable.

Therefore, a well-balanced keto diet includes enough fat so that you are not hungry after a meal and can simply go for several hours without eating nevertheless have ample energy.

Ensure that you increase your intake of fat right from the start of your keto journey.  And once you are fat-adapted, let your appetite guide you on cutting down on fat gradually until you reach a point where maintaining a balance between hunger and satiety is easier for you.

How To Fight Out The Keto Flu?

No doubt the keto flu can make you feel miserable but fortunately, there are ways to reduce its flu-like symptoms and help your body get through the transition period more easily.

Avoid Tiring Exercise

Undoubtedly exercise is important for staying healthy and keeping body weight in check but tiring exercise should be avoided when you are experiencing keto-flu symptoms. Muscle cramps, stomach discomfort and fatigue are quite common in the first week of following a ketogenic diet, so giving your body the required rest would be a good idea.

Intense activities like biking, running, weight lifting and tiring workouts may have to be put aside while your body system adapts to new fuel sources. While avoiding these tiring exercises should be avoided light activities like walking, yoga or leisurely biking may be taken to improve the symptoms.

How To Fight The Keto Flu

Replacing Electrolytes

Substituting dietary electrolytes may help reduce keto-flu symptoms. While following a ketogenic diet, insulin levels in the body decreases, this insulin is an important hormone that helps our body to absorb glucose from the bloodstream. As the insulin levels decrease, the kidneys tend to release excess sodium from the body.

The Keto diet generally restricts many foods that are high in potassium which includes fruits, beans and starchy vegetables. An excellent way to power through the adaptation period of the keto diet is getting adequate amounts of these important nutrients.

Including keto-friendly foods like green leafy vegetables and avocados which are rich in potassium are an excellent way to ensure that you are maintaining a healthy balance of electrolytes. Salting food to taste is another effective way to deal with the symptoms of the keto diet.

These foods seem high in magnesium also which help to reduce muscle cramps, headaches and sleep issues.

Stay Hydrated

Staying hydrated and drinking enough water is necessary for optimal health and can also help reduce symptoms of the keto diet. A keto diet can cause your body to rapidly shed water, increasing the risk of dehydration.

When dietary carbohydrates are reduced in the body, glycogen (the stored form of carbohydrates) levels increases as a result water is excreted from the body. So staying hydrated is the only way through which the symptoms like fatigue and muscle cramping can be fought.

When you kind of experience keto-flu-associated diarrhoea, replacing fluids is utmost important as this may cause additional fluid loss.

Get Adequate Sleep

People who are adapting to a ketogenic diet commonly complain about fatigue and irritability. The levels of the stress hormone cortisol rise in the body due to lack of sleep which negatively impact mood and make keto-flu symptoms worse. 

In case you are having difficulty falling and staying asleep, go through the following tips

  • Caffeine intake should be reduced as it is a stimulant that negatively impacts sleep. If you are the one who drinks caffeine a lot, you should better have it in the morning so that your sleep is not affected.
  • Eliminate ambient light by shutting off cell phones, computers and televisions in the bedroom to promote sound sleep.
  • Take shower by adding Epsom salt or lavender essential oil to your bath is an effective way to relax, wind down and get ready for a good night’s sleep.
  • Waking up early at the same time every day and avoiding oversleeping may help you to normalize your sleep patterns and improve your overall quality of sleep.
  • Eat enough fat as the transition to a very low-carb diet can cause you to crave foods. Food such as cookies, bread, bagels and pasta are strictly restricted on the ketogenic diet. By eating enough fat which is the primary fuel source on the ketogenic diet, you can reduce cravings and keep yourself feeling satisfied. It’s a proven fact that low-carb diets help in reducing cravings for sweets and high-carb foods.

People who are facing a difficult time adapting to the ketogenic diet should eliminate carbohydrates gradually rather than all at once. A gradual process of cutting down carbs while increasing fat and protein in your diet may help in a smoother transition thereby decreasing keto-flu symptoms.

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