Keto Flu Symptoms and How to Reduce Them Effectively

Dieser Artikel basiert auf wissenschaftlichen Studien

Keto Flu | Symptoms | Causes | Duration | Remedy | Conclusion

A ketogenic diet lowers insulin levels, empties carbohydrate stores, and ultimately helps burn fat more efficiently.

Switching your metabolism to ketosis can cause side effects the first time.

The good news is that simple tips are all you need to prevent or alleviate the keto flu. Now let’s take a look together at exactly how this works.

What Is the Keto Flu?

Keto flu is the term used to describe flu-like symptoms that can occur due to switching to a ketogenic diet.

The keto diet aims to burn fat instead of sugar as the primary energy source. The keto flu can occur because, in some cases, your body must first learn to metabolize fat efficiently.

What Are the Symptoms of Keto Flu?

The most common symptoms of the keto flu are (Bostock et al. 20201):

  • Headaches
  • Fatigue
  • Nausea
  • Dizziness
  • Brain fog
  • Gastrointestinal discomfort
  • Low appetite
  • Sugar cravings
  • Other flu symptoms

However, people can experience the keto flu differently. Some even experience chills or fever-like symptoms.

Causes of Keto Flu Symptoms

The leading cause of keto flu symptoms is sodium deficiency.

Some people have a flexible metabolism and can switch effortlessly between glucose and fat burning (Goodpaster et al. 20172).

Keto flu can occur when your body struggles to switch from burning sugar to burning fat. The keto diet lowers insulin levels and allows your body to deplete its carbohydrate stores.

Carbohydrates are stored in glycogen, mainly in the liver and partly in the muscles. Glycogen consists of one part carbohydrate and three parts water.

By breaking down the carbohydrate stores, you lose three to six pounds of water in a few days.

Because insulin binds salt, you excrete more sodium with the water during keto (Tiwari et al. 20073).

This can cause a sodium deficiency, leading to headaches, nausea, fatigue, muscle cramps, and difficulty concentrating (Hurley et al. 20154).

These same symptoms are the most common signs of keto flu.

woman experiences headaches among the symptoms of keto flu

How Long Does the Keto Flu Last?

Usually, symptoms of keto flu last a few days. However, many people experience no signs at all. For a few, symptoms can last for several weeks.

Depending on your lifestyle, the body can make the metabolic change easier or harder.

However, the symptoms are not a must. There are straightforward remedies to relieve the symptoms of keto flu.

How to Reduce Keto Flu Symptoms

The keto flu sounds complex and intimidating. Your antidotes, on the other hand, are amazingly simple.

1. Salt Well

Keto lowers insulin levels. Insulin binds salt in the body. Hence, the kidneys actively remove salt when switching to a ketogenic diet (Tiwari et al. 20075).

Physical symptoms of keto flu, such as headaches or dizziness, are predominantly due to sodium deficiency.

Therefore, most of the symptoms of keto flu disappear with salt consumption.

The craving for salt is natural. Salt, unlike sugar, has a negative feedback loop—salt foods at will on keto. Your body will let you know when it’s enough.

2. Stay Hydrated

In the first few days of the Keto diet, your body flushes out several liters of water.

Accordingly, it would be best to drink diligently to compensate for the fluid loss.

If you are one of the rare cases of diarrhea during the keto flu, you must rehydrate all the more.

In addition to salt, water can help relieve headaches, dizziness, fatigue, and muscle cramps (Popkin et al. 20106).

3. Eat More Healthy Fats

In a society where fat was considered unhealthy for decades, it’s hard to eat it in larger quantities suddenly. The outdated low-fat ideology still shapes our food choices.

When people first remove carbohydrates from their pantry, they often eat too little. The result is cravings – usually for sweets.

But the solution to this problem is simple: more fat.

While satiety hormones increase in proportion to the number of fatty acids consumed, hunger hormones are reduced as a result (Pironi et al. 19937Beck 20068).

We must relearn to replace the high amounts of carbohydrates in our diet with healthy fats. If you find this difficult, you can increase fats step by step.

The basis for your new keto pantry is healthy fats, which you don’t have to skimp on:

  • Virgin coconut oil
  • Extra virgin olive oil
  • Pastured butter

Healthy fats not only keep you fuller longer, but they also taste great. Ideally, you’ll also add them as whole foods, as we’ll see in a moment.

Salmon and spinach help fight the keto flu

4. Supply Electrolytes

In addition to sodium, magnesium, calcium, and potassium help muscles and nerves function correctly (Shrimanker et al. 20209).

These minerals can also be partially flushed out when switching to a ketogenic diet (Tiwari et al. 200710).

Fortunately, the best keto foods are also rich in magnesium, calcium, and potassium (Mg/Ca/K mg per 100 g):

  • Cocoa Nibs (533/250/833*)
  • Spinach (79/99/558*)
  • Macadamia nuts (118/70/363*)
  • Salmon (37/15/628*)
  • Avocados (29/12/485*)
  • Pastured Beef (23/9/342*)
  • Broccoli (19/43/288*)

My pro tip is to drink natural mineral water because it contains sodium, magnesium, calcium, and potassium. Mineral water is the all-in-one remedy for keto flu.

Look at the nutrition facts and make sure the water is highly mineralized. Most major brands are low in electrolytes.

The significant advantage of natural foods is that they don’t contain sugar, sweeteners, flavors, colors, fillers, and lubricants. Also, unlike supplements, you can hardly overdose on them.

5. Don’t Take It Too Easy

You don’t have to take it as easy with the keto flu as with the flu.

Authors that recommend this approach probably have no experience with either ketogenic diets or intermittent fasting 16/8. Both methods inevitably lead to ketosis if done correctly.

If you’re already feeling sluggish, the surest way to eventually feel terrible is to sit around even more.

Fatigue in the first few days of ketogenic eating often indicates that glycogen stores are emptying.

Quickly available energy from carbohydrates becomes scarce while the body first learns to burn fat efficiently for energy.

Physical activity, such as yoga, walking, or gardening, distracts you and forces the body to switch to burning fat.

You still don’t have to overdo it with a 2-hour workout. Moderate exercise is enough to boost fat metabolism.

The Bottom Line

Like keto breath, keto flu is less dangerous than its name sounds.

The best remedies for the keto flu are straightforward: salt and water. Yes, it’s that simple!

If you prepare meals with healthy fats, salt them as you like, and hydrate well, you won’t even feel the keto flu symptoms.

Intermittent Fasting 16/8 for Women Book

Frequently Asked Questions (FAQ)

What does keto flu feel like?

Keto flu may accompany headaches, fatigue, nausea, dizziness, and other flu-like symptoms.

How do I get rid of keto flu?

The easiest way to cure keto flu is to salt and drink well.

Does keto flu mean it's working?

Keto flu means your body is currently relearning to burn fat for energy.



1Bostock ECS, Kirkby KC, Taylor BV, Hawrelak JA. Consumer Reports of “Keto Flu” Associated With the Ketogenic Diet. Front Nutr. 2020;7:20. doi: 10.3389/fnut.2020.00020. eCollection 2020. PubMed PMID: 32232045; PubMed Central PMCID: PMC7082414.

2Goodpaster BH, Sparks LM. Metabolic Flexibility in Health and Disease. Cell Metab. 2017 May 2;25(5):1027-1036. doi: 10.1016/j.cmet.2017.04.015. Review. PubMed PMID: 28467922; PubMed Central PMCID: PMC5513193.

3Tiwari S, Riazi S, Ecelbarger CA. Insulin’s impact on renal sodium transport and blood pressure in health, obesity, and diabetes. Am J Physiol Renal Physiol. 2007 Oct;293(4):F974-84. doi: 10.1152/ajprenal.00149.2007. Epub 2007 Aug 8. Review. PubMed PMID: 17686957.

4Hurley SW, Johnson AK. The biopsychology of salt hunger and sodium deficiency. Pflugers Arch. 2015 Mar;467(3):445-56. doi: 10.1007/s00424-014-1676-y. Epub 2015 Jan 10. Review. PubMed PMID: 25572931; PubMed Central PMCID: PMC4433288.

5Tiwari S, Riazi S, Ecelbarger CA. Insulin’s impact on renal sodium transport and blood pressure in health, obesity, and diabetes. Am J Physiol Renal Physiol. 2007 Oct;293(4):F974-84. doi: 10.1152/ajprenal.00149.2007. Epub 2007 Aug 8. Review. PubMed PMID: 17686957.

6Popkin BM, D’Anci KE, Rosenberg IH. Water, hydration, and health. Nutr Rev. 2010 Aug;68(8):439-58. doi: 10.1111/j.1753-4887.2010.00304.x. Review. PubMed PMID: 20646222; PubMed Central PMCID: PMC2908954.


7Pironi L, Stanghellini V, Miglioli M, Corinaldesi R, De Giorgio R, Ruggeri E, Tosetti C, Poggioli G, Morselli Labate AM, Monetti N. Fat-induced ileal brake in humans: a dose-dependent phenomenon correlated to the plasma levels of peptide YY. Gastroenterology. 1993 Sep;105(3):733-9. doi: 10.1016/0016-5085(93)90890-o. PubMed PMID: 8359644.

8Beck B. Neuropeptide Y in normal eating and in genetic and dietary-induced obesity. Philos Trans R Soc Lond B Biol Sci. 2006 Jul 29;361(1471):1159-85. doi: 10.1098/rstb.2006.1855. Review. PubMed PMID: 16874931; PubMed Central PMCID: PMC1642692.

9Shrimanker I, Bhattarai S. Electrolytes. 2022 Jan;. PubMed PMID: 31082167.

10Tiwari S, Riazi S, Ecelbarger CA. Insulin’s impact on renal sodium transport and blood pressure in health, obesity, and diabetes. Am J Physiol Renal Physiol. 2007 Oct;293(4):F974-84. doi: 10.1152/ajprenal.00149.2007. Epub 2007 Aug 8. Review. PubMed PMID: 17686957.

Mag. Stephan Lederer, MSc. is an author and blogger from Austria who writes in-depth content about health and nutrition. His book series on Interval Fasting landed #1 on the bestseller list in the German Amazon marketplace in 15 categories.

Stephan is a true man of science, having earned multiple diplomas and master's degrees in various fields. He has made it his mission to bridge the gap between conventional wisdom and scientific knowledge. He precisely reviews the content and sources of this blog for currency and accuracy.

Click on the links above to visit his author and about me pages.

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