Scientists from the University of Tasmania found that a ketogenic diet can lead to several flu-like symptoms within the first few weeks on the diet.
The ketogenic diet (keto diet) is a high-fat, low-carbohydrate diet that limits glucose and results in the production of ketones by the liver and their uptake as a different energy source by the brain.
Previous research has found that the keto diet is a treatment for epilepsy.
People also use the keto diet for weight loss, cognitive and memory enhancement, type 2 diabetes, cancer, brain, and mental disorders.
A commonly discussed side effect of the keto diet in media and online forums is “keto flu,” a group of transient symptoms reported as occurring within the first few weeks of a keto diet.
The so-called keto flu is a group of symptoms that may appear two to seven days after starting a ketogenic diet.
Headache, foggy brain, fatigue, irritability, nausea, difficulty sleeping, and constipation are just some of the symptoms of this condition, which are not recognized by medicine.
In the current study, researchers aimed to find the pattern of symptoms, severity, and time course of keto flu as related by users of online forums.
They checked online forums referring to “keto flu,” “keto-induction,” or “keto-adaptation” on Google.
The team analyzed passages describing personal experiences of keto flu and focused on the pattern of symptoms, severity, time course, and remedies proposed.
They identified 43 online forums, which contained 448 posts from 300 unique users.
Descriptors of personal experience of keto flu, reported by 101 of 300 users, included 256 symptom descriptions involving 54 discrete symptoms.
The researchers found the most common symptoms were “flu,” headache, fatigue, nausea, dizziness, “brain fog,” gut discomfort, decreased energy, feeling faint, and heartbeat change.
Symptom reports peaked in the first and dwindled after 4 weeks. Resolution of keto flu symptoms was reported by eight users between days 3 and 30.
The team also found the severity of symptoms, reported by 60 users in 40 forums, was categorized as mild (N = 15), moderate (N = 23), or severe (N = 22). Eighteen remedies were proposed by 121 individual users in 225 posts.
In addition, user conversations were generally supportive, and they shared remedies for keto flu reflecting assumptions of physiological effects of the keto diet.
The team concludes that reports of personal experiences of keto flu by many people suggest the physiological and perhaps psychological changes linked to the keto diet.
It is not clear whether this is to be understood in the form of an illness produced by nutritional and perhaps immune imbalance or is an adaptive bodily process triggered by the keto diet. Future work needs to answer the questions.
The research is published in Frontiers in Nutrition and was conducted by Dr. Emmanuelle Bostock et al.
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