Keto flu is not contagious, but it can make life miserable. How to deal with it?

Keto flu occurs in some individuals who begin the ketogenic diet. Unquestionably, it is related to a sudden reduction in the amount of carbohydrates in the diet and the body’s entry into ketosis. This is a challenging time when he or she must transition from obtaining energy from carbohydrates to fat. The duration of the keto flu varies, but is typically around seven days.

see also : What is a ketogenic diet? How to do it? When it is better to avoid?

what is keto flue?
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Are you planning to follow a ketogenic diet and concerned about developing keto flu? You need not be overly concerned because it does not affect everyone. In addition, you can reduce the likelihood of its occurrence by acting in a manner that facilitates the body’s adaptation to the new diet. Those who previously consumed a great deal of carbohydrates and sugars and then abruptly adopted the ketogenic diet have the highest risk of developing this condition.

What is the keto flu?

The keto flu is a group of symptoms that can happen 2–7 days after starting the ketogenic diet. Keto flu is not a disease, and doctors have never described or researched it. This doesn’t change the fact that there are a lot of stories on the Internet about people who got the so-called “keto flu” after going on a low-carbohydrate diet.

We don’t know how the keto flu happens, and we don’t even know if it’s a specific set of symptoms because similar ones can happen when people switch to, say, an elimination diet or an anti-inflammatory diet or when they stop eating a lot of highly processed foods.

Not everyone who follows the ketogenic diet gets the keto flu. No one knows why some people have it and others don’t. We don’t know if it’s an immune reaction, a change in the microbiome of the intestines, or a shock after a sudden stop of carbohydrates. Ketoflu is not caused by pathogenic microorganisms, and it is not contagious or dangerous to your health or life.

Keto flu: symptoms

Not everyone has the full set of symptoms that are attributed to the keto flu. Some people notice only a few of the following symptoms :

  • stomach pain,
  • constipation or diarrhoea
  • nausea and vomiting
  • muscle and joint pain ,
  • headaches , including migraines,
  • insomnia or excessive sleepiness
  • fatigue and apathy ,
  • mood swings,
  • involuntary muscle contractions,
  • problems with concentration , memory, and logical thinking.

Many of them are like the flu or stomach flu, but the keto flu has nothing to do with the real flu, which is caused by a virus.

Keto flu: sore throat, fever, and chills

These signs don’t appear because you’re following the keto diet and aren’t its result. This doesn’t mean that some people won’t get keto flu during keto flu, but if they do, it will mean that they also have a bacterial or viral infection, which is a separate problem.

The changes in the body that happen when you drastically cut out carbohydrates and eat more fat and protein are not what cause a sore throat, fever, or chills.

How long does the keto flu last?

It usually lasts about a week, but everyone is different, and we don’t know what makes the symptoms of the keto flu last as long as they do. Some people get better and get rid of them quickly, like in 4 days, while others have to deal with them for up to a month. The good news is that they go away on their own in the long run.

Keto flu: what to do?

Since keto flu is not a disease entity, there are no official guidelines on how to deal with it. Therefore, most often the whole “treatment” consists in the temporary alleviation of symptoms.

However, it is best to try to prevent it by doing the following:

  • Switch to the keto diet gradually, not overnight,
  • take care of proper hydration of the body ,
  • Do not drastically reduce the amount of salt in the diet; the keto diet “flushes” it (electrolytes will ensure hydration and supply of mineral salts).
  • Do not avoid fat in the initial phase of the diet; it is from it that the body will draw energy before it adapts to drawing more from its own adipose tissue.
  • Eat often but in smaller portions.
  • rest ,
  • give up coffee and alcohol.

Most of these tips are worth implementing when keto flu symptoms appear. In the case of severe headaches or muscle and joint pain, they can be temporarily relieved with commonly available painkillers . If you feel very unwell, you should contact your doctor, as it may be the result not only of switching to the keto diet but also of infection.


What is a ketogenic diet? How to do it? When it is better to avoid?

A diet that is very low in carbohydrates and very high in fat.

The goal of a ketogenic diet is to get tissues that can use fat and ketones as fuel instead of carbs to do so. During a ketogenic diet, it is usually recommended to get most of your calories from fat and ketones.

What is a ketogenic diet
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  • 5% (45-60%)  carbohydrates
  • 20% (10-12%)  protein
  • 75% (20-35%) fat.

In some cases, less extreme fat-to-protein ratios are used, like 60% protein and 35% fat. However, the common denominator is always a carbohydrate intake so low that it forces the body into a state of ketosis.

Compared to other popular diets of this time (Paleo, Dukan, etc. ), the ketogenic diet often has a very high fat content (up to 70%–80%) and only a moderate amount of protein. This is because too much protein can make it harder to get into ketosis because some amino acids can be turned into glucose.

For the sake of clarity, it’s important to say that a ketogenic diet always involves going into ketosis, so it is NOT the same as:

  • high protein diet
  • low-carb diet (of which it represents an extreme type).

What foods are allowed?

To get into and stay in ketosis, it’s best to eat foods that are very low in carbohydrates and high in fat, which is a macronutrient that gets a lot of attention.

  • some forms of animal fats (lard, butter, aged cheeses, Greek yoghurt, etc.)
  • most vegetable oils (olive, palm, and coconut),
  • fatty foods in general, such as avocados and nuts (walnuts, macadamia nuts, almonds, pecans)
  • seeds (sunflower, pumpkin, sesame, hemp, flax)

Protein is moderate, so it is important to choose cuts of beef fed on hay and free-range poultry with higher omega-3 fats and greater animal welfare, as well as freedom for other meats, fish, wild eggs, and tofu.

Non-starchy vegetables include leafy greens, brassicas, peppers, onions, garlic, mushrooms, cucumbers, celery, and zucchini. Carrots and tomatoes should be avoided due to their low carbohydrate content.

When it comes to fruit, small portions of berries are okay, and other fruits that aren’t very high in carbs can be added in very small amounts, but you have to be careful not to go over the daily limit (peach, watermelon, etc.).

No problem with unsweetened cocoa, but it must be at least 90%, and then certainly drinks such as unsweetened coffee and tea .

There are a lot of industrial preparations on the market today that were made so they could be eaten on low-carb or even ketogenic diets. Unfortunately, many of these are highly processed foods with a lot of additives that should be limited for health reasons.

What foods are prohibited?

On the diet, you can’t eat any foods that have a lot of carbohydrates, such as:

  • All cereals, no matter if they are whole or refined, as well as all starchy foods and all foods with added or natural sugars;
  • Legumes, including peanuts, which, yes, are legumes;
  • starchy vegetables like potatoes, corn, and winter squash
  • Fruit, barring the exceptions seen above or really moderate quantities (how much sense does it make to eat a slice of apple?).

Hard alcohol and low-carb wines and beers, but not sugary cocktails, are limited by the programmes. Dairy products are looked at on a case-by-case basis.

Ketogenic Diet for Medical Purposes

In the 1920s, before insulin was discovered, people with diabetes were put on ketogenic diets, which cut back on carbs to lower the amount of sugar in the blood. The evidence of effectiveness is good, and some endocrinologists still resort to this approach today. Other less restrictive and more focused regimes on the choice of carbohydrates have also been used successfully. Ketogenic diets are typically low in animal fats and calories and aimed at weight loss.

This diet is used for the treatment of forms of childhood epilepsy that do not respond to traditional drugs, as well as weight loss in a broad sense. Trials are underway to explore its effectiveness on other conditions, such as tumours, dementia, and Parkinson’s disease.

Can you lose weight on the ketogenic diet?

The ketogenic diet is beneficial for weight loss, but it is limited to the short term and has no advantages in terms of “how much weight you lose” compared to other diets.

Fats and proteins have a long-lasting satiating effect, reducing appetite and making meal times less lively. For some patients, no caloric limit is imposed, allowing them to eat as much as they want.

Biasci’s book, Project Nutrition, shows that when comparing a ketogenic diet with a more balanced one, the weight loss is comparable, except for the amount of liquids lost in the first few days. This is likely due to factors such as the ease with which many subjects manage to lose weight.

  • reduction in energy efficiency (ketone bodies only let you get back some of the energy stored in fat), but most importantly,
  • increased sense of satiety,
  • Because there were so few foods to choose from, people ate fewer calories on their own.
  • A great psychological incentive linked to the rapid loss of the first few kilos is, however, linked to liquids.

The ketogenic approach is a limited-time diet, with a time frame of less than 3 weeks. It’s not a good way to eat all the time, but it can help you lose weight.


Ketogenic diets are controversial and don’t really work for certain groups of people.

Exclusion diets can be harmful because they leave out foods that have been shown to help fight diseases. They also expose people to the risk of micronutrient deficiencies, such as vitamin-mineral integrations.

Because it leaves out foods that have been shown to help protect against diseases, an exclusion diet is a dangerous way to live. It also exposes one to the risk of micronutrient deficiencies and does not allow for mistakes, which can have psychological and social repercussions. Vegetarians and vegans are limited to tofu and little else to ensure a proper protein intake.

Risks and side effects

The ketogenic diet is safe for up to 2 years, as ketone bodies are produced in small concentrations without alterations in blood pH. Unlike diabetic ketoacidosis, the organism never loses control of the production of ketones and cannot exceed the critical threshold.

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