Consumer Reports of “Keto Flu” Associated With the Ketogenic Diet

Abstract

Background: The ketogenic diet (KD) is a high-fat, low-carbohydrate diet that limits glucose and results in the production of ketones by the liver and their uptake as an alternative energy source by the brain. KD is an evidence-based treatment for intractable epilepsy. KD is also self-administered, with limited evidence of efficacy, for conditions including weight loss, cognitive and memory enhancement, type II diabetes, cancer, neurological and psychiatric disorders. A commonly discussed side effect of KD in media and online forums is "keto flu," a cluster of transient symptoms generally reported as occurring within the first few weeks of KD. This study aimed to characterize the pattern of symptoms, severity and time course of keto flu as related by users of online forums.Method: Online forums referring to "keto flu," "keto-induction," or "keto-adaptation" in the URL were identified in Google. Passages describing personal experiences of keto flu were categorized manually with reference to pattern of symptoms, severity, time course, and remedies proposed.Results: The search criteria identified 75 online forums, 43 met inclusion criteria and contained 448 posts from 300 unique users. Seventy-three made more than one post (mean 3.12, range 2-11). Descriptors of personal experience of keto flu, reported by 101 of 300 users, included 256 symptom descriptions involving 54 discrete symptoms. Commonest symptoms were "flu," headache, fatigue, nausea, dizziness, "brain fog," gastrointestinal discomfort, decreased energy, feeling faint and heartbeat alterations. 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 (median 4.5, IQR 3-15). 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.Conclusions: Typically, individual posts provided fragmentary descriptions related to the flow of forum conversations. A composite picture emerged across 101 posts describing personally experienced symptoms. User conversations were generally supportive, sharing remedies for keto flu reflecting assumptions of physiological effects of KD.

Effects of the Ketogenic Diet on Glycemic Control in Diabetic Patients: Meta-Analysis of Clinical Trials

“…The idea of a ketogenic diet is to consume more calories from fat and less from carbohydrates in order to shift the basis of energy production from glucose to ketone bodies created from fat breakdown [ 4 ]. Side effects are usually mild and short in duration like headache, diarrhea, frequent urination, sweating, fatigue, hunger, anxiety and/or irritability, tachycardia, lightheadedness, and shakiness [ 5 ]. In the past, the use of the diet was for the treatment of refractory seizures in children.…”

Therapeutic use of intermittent fasting and ketogenic diet as an alternative treatment for type 2 diabetes in a normal weight woman: a 14-month case study

“…Our patient tolerated the KD well, with her only reported difficulty being the week-long initial period of adjustment, termed in popular media as keto flu and in the medical literature as keto induction. 34 Common symptoms of keto flu include influenzalike symptoms, headache, fatigue, nausea, dizziness, gastrointestinal discomfort and decreased energy. 34 The symptoms tend to peak within the first 7 days of initiating a KD and resolve within the first month.…”

“…34 Common symptoms of keto flu include influenzalike symptoms, headache, fatigue, nausea, dizziness, gastrointestinal discomfort and decreased energy. 34 The symptoms tend to peak within the first 7 days of initiating a KD and resolve within the first month. 34 While data show that IF and the production of ketone bodies result in adaptive responses that influence health and longevity, further research on KDs is needed to help support their widespread use in the treatment of diabetes mellitus.…”

Popular Diets: Ketogenic Diet

“…The ketogenic diet may have negative health and wellness effects. In the short term, some individuals following a ketogenic diet have reported flu-like symptoms, including headache, fatigue, nausea, dizziness, gastrointestinal disorders, and decreased energy, among others (Bostock et al 2020). Lethargy, dehydration, acidosis, mood changes, and increases in infections, vomiting, and constipation have been reported during the first days of usage of ketogenic diet in some children with epilepsy (Vining et al 1998).…”