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Front. Nutr., 17 December 2020
Sec. Clinical Nutrition

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

  • 1Menzies Institute for Medical Research, Hobart, TAS, Australia
  • 2Psychiatry, University of Tasmania, Hobart, TAS, Australia
  • 3Neurology, Menzies Institute for Medical Research, Hobart, TAS, Australia
  • 4College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
  • 5Australian Research Centre for Complementary and Integrative Medicine, University of Technology Sydney, Ultimo, NSW, Australia

A Commentary on
Commentary: Consumer Reports of “Keto Flu” Associated With the Ketogenic Diet

by Sáenz de Pipaón, M., Flores-Rojas, K., Gil, A., and Gil-Campos, M. (2020). Front. Nutr. 7:113. doi: 10.3389/fnut.2020.00113

We thank the authors of the commentary on our paper Consumer reports of “Keto Flu” associated with the Ketogenic Diet (1) for sharing their concerns regarding the use of gray literature, in this case posts on online forums. As we read it, the central thesis of the commentary is that gray literature is inherently unreliable and should not be investigated unless there is a firmly grounded scientific understanding of the phenomenon. We do not fundamentally disagree with this proposition but regard the matter as undecided and wish to place discussion of the method in a broader context, as follows.

In our view the commentary does not address the main point, namely that for many health conditions and many putative treatments, there are a variety of narratives circulating in society. These typically include a scientific narrative and a consumer narrative, which may be broadly characterized as having a methodological and an experiential focus, respectively. We regard both as potentially “legitimate sources of information,” though either may not necessarily be a “source of legitimate information” on any given aspect. In other words, it is possible to accurately summarize both narratives, or aspects thereof, but whether they are true (Oxford English Dictionary: in accordance with fact or reality) or not is a different matter.

We contend that the scientific and consumer narratives are not mutually exclusive, and that both are subject to potential bias and may contain fraudulent or spurious material. Accordingly, we would rather see the study of consumer narratives incorporated as a standard component of the scientific agenda, the utility of this approach being determined on its merits. This would include the proviso that ethical considerations are met. This direction would complement moves to make scientific narratives available to consumers, for example through open access publishing, by rendering consumer narratives accessible to scientists.

Sharing, contesting, and informing the ideas in both the scientific and consumer narratives is the desired outcome.

With respect to specific issues raised in the commentary. The media report widely and with varying degrees of accuracy on many published journal articles and this possibility cannot govern the publication of results. There is a vast amount of consumer comment available through the internet and it would be impractical for interested parties to keep up with the full content. We believe that methods are required which accurately summarize this material with respect to the particular topic of enquiry. In our paper the topic was side effects of ketogenic diets (KD) and the focus within this category was in what is popularly termed “keto flu,” as discussed in online forums on this subject. Whether the aggregate of consumer comments in online forums is less reliable than conventional questionnaire-based methods is an empirical question. We have an open mind as to whether joining an online conversation, contemplating one's own experience and formulating this in writing in a form of public space is more or less reliable than scoring a questionnaire item or responding ad-hoc to a semi-structured interview question on a given side effect. It will be interesting to see how this field evolves.

The commentators have noted that ancillary information such as level of education and type of KD would assist in interpreting the results. We agree but have noted that for ethical reasons we did not analyse or report on personal information but rather confined our attention to the principal aim of discerning the pattern of side effects.

The analysis of gray literature is a growing area of research and the results of further studies will inform discussion of the merit and limitations of this approach. Between January and September 2020 twelve publications listed on PubMed reported analyses of online forum/ discussion board content. These covered a variety of topics, including irritable bowel syndrome (2), ketamine use in depression and post-traumatic stress disorder (3), and information seeking and sharing practices in breastfeeding mothers (4).

Author Contributions

EB, KK, BT, and JH contributed equally to the response to the commentary. All authors contributed to the article and approved the submitted version.

Conflict of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


1. Bostock 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

PubMed Abstract | CrossRef Full Text | Google Scholar

2. Teasdale E, Clarke H, Chen N, Everitt H. Online forum users' views and experiences of managing irritable bowel syndrome: a qualitative analysis of discussion content. BJGP Open. (2020). doi: 10.3399/bjgpopen20X101084. [Epub ahead of print].

PubMed Abstract | CrossRef Full Text | Google Scholar

3. Chaves TV, Wilffert B, Sanchez ZM. The use of ketamine to cope with depression and post-traumatic stress disorder: a qualitative analysis of the discourses posted on a popular online forum. Am J Drug Alcohol Abuse. (2020) 46:613–24. doi: 10.1080/00952990.2020.1769118

PubMed Abstract | CrossRef Full Text | Google Scholar

4. Lebron CN St, George SM, Eckembrecher DG, Alvarez LM. “Am I doing this wrong?” Breastfeeding mothers' use of an online forum. Matern Child Nutr. (2020) 16:e12890. doi: 10.1111/mcn.12890

PubMed Abstract | CrossRef Full Text | Google Scholar

Keywords: ketogenic diet, ‘keto flu', symptoms, online forums, scientific method

Citation: Bostock ECS, Kirkby KC, Taylor BV and Hawrelak JA (2020) Response: Commentary: Consumer Reports of “Keto Flu” Associated With the Ketogenic Diet. Front. Nutr. 7:575713. doi: 10.3389/fnut.2020.575713

Received: 24 June 2020; Accepted: 30 November 2020;
Published: 17 December 2020.

Edited by:

Nada Rotovnik Kozjek, Institute of Oncology Ljubljana, Slovenia

Reviewed by:

Caterina Conte, Università telematica San Raffaele, Italy

Copyright © 2020 Bostock, Kirkby, Taylor and Hawrelak. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Emmanuelle C. S. Bostock,

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