Reports of flu-like symptoms seen with Keto diet

A new study has shown that those starting on a keto diet could develop certain flu-like symptoms in the initial weeks. The study titled, “Consumer Reports of “Keto Flu” Associated With the Ketogenic Diet,” was published in the latest issue of the journal Frontiers in Nutrition.

Australian researchers from the University of Tasmania have found that within the first seven days of starting a keto diet, many individuals complain of flu-like symptoms. These symptoms often recede within the first four weeks of the diet. The symptoms include fatigue, dizziness, nausea, palpitations, etc.

What is Keto diet?

The ketogenic diet or keto diet is a special type of diet adopted by weight watchers and those seeking to reduce weight. It is typically low on carbohydrates and high on fats and proteins. This type of diet reduces the glucose intake severely, which leads to the formation and release of ketones from the liver. These ketones are generally not used by the body for releasing energy.

Consumer Reports of “Keto Flu” Associated With the Ketogenic Diet. Keto, ketogenic diet, low carb, high fat healthy weight loss meal plan. Image Credit: SewCream / Shutterstock
Consumer Reports of “Keto Flu” Associated With the Ketogenic Diet. Keto, ketogenic diet, low carb, high fat healthy weight loss meal plan. Image Credit: SewCream / Shutterstock S By

During a keto diet, ketones are utilized by the body for the release of energy for the brain because of the absence of glucose. Apart from weight loss, several disease conditions, including epilepsy, have also shown to benefit from the keto diet.

People with type 2 diabetes, dementia, psychiatric conditions, and neurological diseases and cancers also take on keto diets to obtain health benefits. None of these claims, however, have a scientific basis, say the researchers.

What was the study about?

According to researchers, people having a keto diet often complain of “keto-flu” on social media. They attempted to study the basis of these claims. The team looked at the pattern of the symptoms of keto flu as well as their time duration and severity among those reporting it on online forums.

Dr. Emmanuelle Bostock of the Menzies Institute for Medical Research of the University of Tasmania in Australia said, “The experiences of symptoms by many people strengthens the evidence for side-effects following the initiation of a ketogenic diet. These consumers have the most direct experience of effects and side-effects, and many choose to report and share these in online forums.”

What was done?

For this study, the team searched for keywords such as “keto flu,” “keto-induction,” or “keto-adaptation” in the URL on Google. They found several reports and passages where internet user had described their personal experiences with the keto flu. Each of these reports was then categorized manually, and the severity of the symptoms, time course of the symptoms, possible remedies are taken, were studied, and noted.

“We focused on social media because of its widespread use for discussion of health topics, which makes it practical to harness the experience of people who have tried the treatment in question,” said Bostock. She added, “In the present study, we responsibly and respectfully used public domain online forum posts and analyzed their content to produce new insights into side-effects of the ketogenic diet.”

What was found?

Results revealed that there were 75 online forums that contained the keywords. Of these 43 met the criteria that were predetermined for inclusion into the study. From these online forums, a total of 448 posts were found related to the keywords. Of these, there were 300 unique users noted. The team found that 73 of the users had made more than one report and posted an average of 3.12 times regarding their symptoms. Of these 300 users, 101 described their personal experiences with the keto flu. A total of 256 such symptoms were found from the reports, of which 54 were unique or discrete symptoms. Some of these symptoms include:

  • Flu headache
  • Fatigue
  • Dizziness
  • Nausea
  • “brain fog”
  • Reduced energy
  • Feeling faint
  • Gastrointestinal upset or discomfort
  • Palpitations or alterations of heartbeat

On looking at the time course of these symptoms, the team noted that the symptoms usually rose to their greatest intensity within the first week of initiating the diet and subsided by the fourth week in most. There was a range of 3 and 30 days in resolution of the symptoms of the keto flu.

The severity of the symptoms was reported by 60 users across 40 forums. The researchers categorized the intensity of the symptoms as;

  • Mild among 15 users
  • Moderate among 23 users
  • Severe among 22 users

They noted that 121 users of these online forums reported 18 different remedies for the keto flu in 225 different posts.

Implications and future directions

This was a “fragmented” picture of the pattern of symptoms and their time course and severity of keto flu among online users, concluded the researchers. They wrote in conclusions, “User conversations were generally supportive, sharing remedies for keto flu reflecting assumptions of physiological effects of KD.” Bostock concluded, “Taken together, such reports can bring an illness or side effects into focus and can complement clinical observations and questionnaire-based research. We see potential for research of this nature to inform all aspects of health care on a continuous basis.”

Journal reference:

Emmanuelle C. S. Bostock, Kenneth C. Kirkby, Bruce V. Taylor and Jason A. Hawrelak, Consumer Reports of “Keto Flu” Associated With the Ketogenic Diet, Front. Nutr., 13 March 2020 |

Dr. Ananya Mandal

Written by

Dr. Ananya Mandal

Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.


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