According to the study, published in the journal Frontiers in Nutrition, these symptoms peak in the first seven days and dwindle after four weeks and range in
These reports reveal common but yet unknown symptoms, such as flu fatigue, nausea, dizziness, decreased energy, feeling faint and heartbeat alterations.
"The experiences of symptoms by many people strengthens the evidence for side-effects following the initiation of a ketogenic diet," said study researcher
"These consumers have the most immediate experience of effects and side-effects and many choose to report and share these in online forums," Bostock added.
According to the researchers, a commonly discussed side effect of this diet is the so-called "keto flu", a cluster of transient symptoms that occur within the first few weeks on the diet.
To better understand how these symptoms evolve, the research team identified 43 online forums referring to "keto flu" and manually gathered personal experiences of 101 people describing symptoms, severity and time course.
"In the present study, we responsibly and respectfully used public domain online forum posts and analysed their content to produce new insights into side-effects of the ketogenic diet," Bostock said.
In line with prior medical research, the researchers found reports of headache, difficulty concentrating and gastrointestinal discomfort, following the initiation of a keto diet.
Additionally, they revealed further common symptoms, such as flu, fatigue, nausea, dizziness, decreased energy, feeling faint and heartbeat alterations.
Consumers often experienced more than one symptom, with differing degrees of severity, the study said.
According to ther researchers, there is also good news for people experiencing such a "keto flu".
The results of this study highlight the sudden onset of symptoms, peaking in the first and dwindling after four weeks.
Once symptoms manifested, most of them resolved within little more than two weeks, according to the research.