International consensus on fasting terminology

Daniela A Koppold¹, Carolin Breinlinger², Etienne Hanslian³, Christian Kessler⁴, Holger Cramer⁵, Anika Rajput Khokhar⁶, Courtney M Peterson⁷, Grant Tinsley⁸, Claudio Vernieri⁹, Richard J Bloomer¹⁰, Michael Boschmann¹¹, Nicola L Bragazzi¹², Sebastian Brandhorst¹³, Kelsey Gabel¹⁴, Alan C Goldhamer¹⁵, Martin M Grajower¹⁶, Michelle Harvie¹⁷, Leonie Heilbronn¹⁸, Benjamin D Horne¹⁹, Spyridon N Karras²⁰, Jost Langhorst²¹, Eva Lischka²², Frank Madeo²³, Sarah J Mitchell²⁴, Ioannis-Eleemon Papagiannopoulos-Vatopaidinos²⁵, Maria Papagiannopoulou²⁶, Hanno Pijl²⁷, Eric Ravussin²⁸, Martha Ritzmann-Widderich²⁹, Krista Varady¹⁴, Lilian Adamidou³⁰, Melika Chihaoui³¹, Rafael de Cabo³², Mohamed Hassanein³³, Nader Lessan³⁴, Valter Longo³⁵, Emily N C Manoogian³⁶, Mark P Mattson³⁷, J Brent Muhlestein³⁸, Satchidananda Panda³⁶, Sousana K Papadopoulou³⁹, Nikolaos E Rodopaios⁴⁰, Rainer Stange⁴, Andreas Michalsen⁴

Affiliations

¹ Institute of Social Medicine, Epidemiology and Health Economics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany; Department of Internal Medicine and Nature-Based Therapies, Immanuel Hospital Berlin, 14109 Berlin, Germany; Charité Competence Center for Traditional and Integrative Medicine (CCCTIM), Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany. Electronic address: daniela.koppold@charite.de.
² Institute of Social Medicine, Epidemiology and Health Economics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany. Electronic address: carolin.breinlinger@charite.de.
³ Institute of Social Medicine, Epidemiology and Health Economics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany.
⁴ Institute of Social Medicine, Epidemiology and Health Economics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany; Department of Internal Medicine and Nature-Based Therapies, Immanuel Hospital Berlin, 14109 Berlin, Germany.
⁵ Institute for General Practice and Interprofessional Care, University Hospital Tübingen, Tübingen, Germany; Robert Bosch Center for Integrative Medicine and Health, Bosch Health Campus, Stuttgart, Germany.
⁶ Institute of Social Medicine, Epidemiology and Health Economics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany; Department of Dermatology, Venereology and Allergology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
⁷ Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA.
⁸ Department of Kinesiology & Sport Management, Texas Tech University, Lubbock, TX 79409, USA.
⁹ Medical Oncology Department, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; IFOM ETS, the AIRC Institute of Molecular Oncology, Milan, Italy.
¹⁰ College of Health Sciences, The University of Memphis, Memphis, TN 38152, USA.
¹¹ Experimental & Clinical Research Center - A joint co-operation between Charité Universitätsmedizin und Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Clinical Research Unit, Berlin, Germany.
¹² Department of Mathematics and Statistics, Laboratory for Industrial and Applied Mathematics (LIAM), York University, Toronto, ON, Canada.
¹³ Longevity Institute, Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA.
¹⁴ Department of Kinesiology and Nutrition, University of Illinois at Chicago, 1919 West Taylor Street, Chicago, IL 60612, USA.
¹⁵ TrueNorth Health Foundation, Santa Rosa, CA 95404, USA; TrueNorth Health Center, Santa Rosa, CA 95404, USA.
¹⁶ Division of Endocrinology, Albert Einstein College of Medicine, Bronx, New York, NY, USA.
¹⁷ Prevent Breast Cancer Research Unit, The Nightingale Centre, Manchester University NHS Foundation Trust, Manchester, England; Division of Cancer Sciences, The University of Manchester, Manchester, England.
¹⁸ Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia; Nutrition, Metabolism & Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, Australia.
¹⁹ Intermountain Medical Center Heart Institute, Salt Lake City, UT, USA; Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA.
²⁰ Laboratory of Biological Chemistry, Medical School, Aristotle University, 54636 Thessaloniki, Greece.
²¹ Department for Internal and Integrative Medicine, Sozialstiftung Bamberg Hospital, Bamberg, Germany; Department for Integrative Medicine, University of Duisburg-Essen, Medical Faculty, Bamberg, Germany.
²² Klinik Buchinger Wilhelmi, Überlingen, Germany.
²³ BioTechMed Graz, Graz, Austria; Institute of Molecular Biosciences, University of Graz, Graz, Austria; Field of Excellence BioHealth, University of Graz, Graz, Austria.
²⁴ Ludwig Princeton Branch, Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA.
²⁵ Vatopaidi Monastery Hospital, 63086 Mount Athos, Greece.
²⁶ Medical Office for Fasting Therapy, Danaedon 24A, Chalandri, 15232 Athens, Greece.
²⁷ Department of Internal Medicine, Leiden University Medical Center, Leiden, the Netherlands.
²⁸ Pennington Biomedical Research Center, Baton Rouge, LA, USA.
²⁹ Praxis für Ernährungsmedizin und Prävention in Rottweil, Hochbrücktorstraße 22, 78628 Rottweil, Germany.
³⁰ Department of Dietetics and Nutrition, AHEPA University Hospital, Thessaloniki, Greece.
³¹ Department of Endocrinology, University Hospital La Rabta, Faculty of medicine of Tunis, University Tunis El Manar, Tunis, Tunisia.
³² Experimental Gerontology Section, Translational Gerontology Branch, National Institute on Aging, Baltimore, MD, USA.
³³ Department of Endocrinology and Diabetes, Dubai Hospital, Dubai Academic Health Cooperation, United Arab Emirates.
³⁴ The Research Institute, Imperial College London Diabetes Centre, Abu Dhabi, United Arab Emirates.
³⁵ IFOM ETS, the AIRC Institute of Molecular Oncology, Milan, Italy; Longevity Institute, Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA.
³⁶ Regulatory Biology Department, Salk Institute for Biological Studies, La Jolla, CA, USA.
³⁷ Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
³⁸ The Intermountain Medical Center, Murray, UT, USA.
³⁹ Department of Nutritional Sciences and Dietetics, School of Health Sciences, International Hellenic University, 57001 Thessaloniki, Greece.
⁴⁰ Department of Social Medicine, Preventive Medicine and Nutrition Clinic, School of Medicine, University of Crete, Voutes, 71003 Iraklion, Greece.

PMID: 39059384
PMCID: PMC11504329
DOI: 10.1016/j.cmet.2024.06.013

International consensus on fasting terminology

Daniela A Koppold et al. Cell Metab. 2024.

. 2024 Aug 6;36(8):1779-1794.e4.

doi: 10.1016/j.cmet.2024.06.013. Epub 2024 Jul 25.

Authors

Affiliations

¹ Institute of Social Medicine, Epidemiology and Health Economics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany; Department of Internal Medicine and Nature-Based Therapies, Immanuel Hospital Berlin, 14109 Berlin, Germany; Charité Competence Center for Traditional and Integrative Medicine (CCCTIM), Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany. Electronic address: daniela.koppold@charite.de.
² Institute of Social Medicine, Epidemiology and Health Economics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany. Electronic address: carolin.breinlinger@charite.de.
³ Institute of Social Medicine, Epidemiology and Health Economics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany.
⁴ Institute of Social Medicine, Epidemiology and Health Economics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany; Department of Internal Medicine and Nature-Based Therapies, Immanuel Hospital Berlin, 14109 Berlin, Germany.
⁵ Institute for General Practice and Interprofessional Care, University Hospital Tübingen, Tübingen, Germany; Robert Bosch Center for Integrative Medicine and Health, Bosch Health Campus, Stuttgart, Germany.
⁶ Institute of Social Medicine, Epidemiology and Health Economics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany; Department of Dermatology, Venereology and Allergology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
⁷ Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA.
⁸ Department of Kinesiology & Sport Management, Texas Tech University, Lubbock, TX 79409, USA.
⁹ Medical Oncology Department, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; IFOM ETS, the AIRC Institute of Molecular Oncology, Milan, Italy.
¹⁰ College of Health Sciences, The University of Memphis, Memphis, TN 38152, USA.
¹¹ Experimental & Clinical Research Center - A joint co-operation between Charité Universitätsmedizin und Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Clinical Research Unit, Berlin, Germany.
¹² Department of Mathematics and Statistics, Laboratory for Industrial and Applied Mathematics (LIAM), York University, Toronto, ON, Canada.
¹³ Longevity Institute, Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA.
¹⁴ Department of Kinesiology and Nutrition, University of Illinois at Chicago, 1919 West Taylor Street, Chicago, IL 60612, USA.
¹⁵ TrueNorth Health Foundation, Santa Rosa, CA 95404, USA; TrueNorth Health Center, Santa Rosa, CA 95404, USA.
¹⁶ Division of Endocrinology, Albert Einstein College of Medicine, Bronx, New York, NY, USA.
¹⁷ Prevent Breast Cancer Research Unit, The Nightingale Centre, Manchester University NHS Foundation Trust, Manchester, England; Division of Cancer Sciences, The University of Manchester, Manchester, England.
¹⁸ Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia; Nutrition, Metabolism & Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, Australia.
¹⁹ Intermountain Medical Center Heart Institute, Salt Lake City, UT, USA; Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA.
²⁰ Laboratory of Biological Chemistry, Medical School, Aristotle University, 54636 Thessaloniki, Greece.
²¹ Department for Internal and Integrative Medicine, Sozialstiftung Bamberg Hospital, Bamberg, Germany; Department for Integrative Medicine, University of Duisburg-Essen, Medical Faculty, Bamberg, Germany.
²² Klinik Buchinger Wilhelmi, Überlingen, Germany.
²³ BioTechMed Graz, Graz, Austria; Institute of Molecular Biosciences, University of Graz, Graz, Austria; Field of Excellence BioHealth, University of Graz, Graz, Austria.
²⁴ Ludwig Princeton Branch, Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA.
²⁵ Vatopaidi Monastery Hospital, 63086 Mount Athos, Greece.
²⁶ Medical Office for Fasting Therapy, Danaedon 24A, Chalandri, 15232 Athens, Greece.
²⁷ Department of Internal Medicine, Leiden University Medical Center, Leiden, the Netherlands.
²⁸ Pennington Biomedical Research Center, Baton Rouge, LA, USA.
²⁹ Praxis für Ernährungsmedizin und Prävention in Rottweil, Hochbrücktorstraße 22, 78628 Rottweil, Germany.
³⁰ Department of Dietetics and Nutrition, AHEPA University Hospital, Thessaloniki, Greece.
³¹ Department of Endocrinology, University Hospital La Rabta, Faculty of medicine of Tunis, University Tunis El Manar, Tunis, Tunisia.
³² Experimental Gerontology Section, Translational Gerontology Branch, National Institute on Aging, Baltimore, MD, USA.
³³ Department of Endocrinology and Diabetes, Dubai Hospital, Dubai Academic Health Cooperation, United Arab Emirates.
³⁴ The Research Institute, Imperial College London Diabetes Centre, Abu Dhabi, United Arab Emirates.
³⁵ IFOM ETS, the AIRC Institute of Molecular Oncology, Milan, Italy; Longevity Institute, Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA.
³⁶ Regulatory Biology Department, Salk Institute for Biological Studies, La Jolla, CA, USA.
³⁷ Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
³⁸ The Intermountain Medical Center, Murray, UT, USA.
³⁹ Department of Nutritional Sciences and Dietetics, School of Health Sciences, International Hellenic University, 57001 Thessaloniki, Greece.
⁴⁰ Department of Social Medicine, Preventive Medicine and Nutrition Clinic, School of Medicine, University of Crete, Voutes, 71003 Iraklion, Greece.

PMID: 39059384
PMCID: PMC11504329
DOI: 10.1016/j.cmet.2024.06.013

Abstract

Although fasting is increasingly applied for disease prevention and treatment, consensus on terminology is lacking. Using Delphi methodology, an international, multidisciplinary panel of researchers and clinicians standardized definitions of various fasting approaches in humans. Five online surveys and a live online conference were conducted with 38 experts, 25 of whom completed all 5 surveys. Consensus was achieved for the following terms: "fasting" (voluntary abstinence from some or all foods or foods and beverages), "modified fasting" (restriction of energy intake to max. 25% of energy needs), "fluid-only fasting," "alternate-day fasting," "short-term fasting" (lasting 2-3 days), "prolonged fasting" (≥4 consecutive days), and "religious fasting." "Intermittent fasting" (repetitive fasting periods lasting ≤48 h), "time-restricted eating," and "fasting-mimicking diet" were discussed most. This study provides expert recommendations on fasting terminology for future research and clinical applications, facilitating communication and cross-referencing in the field.

Keywords: Delphi method; alternate-day fasting; dry fasting; fasting; fasting-mimicking diet; intermittent energy restriction; intermittent fasting; periodic fasting; therapeutic fasting; time-restricted eating.

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Conflict of interest statement

Declaration of interests D.A.K. and A.M. are members of the steering committee of the German Medical Association for Fasting and Nutrition (ÄGHE). D.A.K. has co-founded the Academy of Integrative Fasting (AIF), an institution for the qualification of medical staff in clinical fasting applications. D.A.K. serves as a consultant for a mobile application on intermittent fasting (FASTIC) as well as a company producing plant-based supplements (EVERYYIN). A.M. is also co-founder of the SALUFAST company. A.M. serves as a consultant for Lanserhof. E.H. and A.R.K. are members of the steering committee of the German Medical Association for Fasting and Nutrition (ÄGHE). C.M.P. receives grant funding from the National Institutes of Health and the Department of Defense to study intermittent fasting. G.T. is an inventor on the international patent “Compositions and methods of use of beta-hydroxy beta-methylbutyrate (HMB) associated with intermittent fasting.” C.V. is on the advisory board for Novartis, Eli Lilly, Pfizer, Menarini and Daiichi Sankyo. He receives honoraria as a speaker from Novartis, Eli Lilly, Istituto Gentili, Accademia di Medicina and research grants from Roche. C.V. is supported by AIRC (Associazione Italiana per la ricerca sul Cancro) MFAG 22977, ERC (European Research Council) METABALANCANCER - 101117893, Giuliani Foundation: Fondazione Gianmaria e Sabrina Giuliani. R.J.B. is a consultant to CalerieHealth and Tecton, and coauthor of The Daniel Cure: The Daniel Fast Way to Vibrant Health. K.G. disclosed receipt of the following financial support: the National Institutes of Health (12HD101373 and 5P30AG022849). A.C.G. owns a facility that offers fasting supervision. He is on the board of a non-profit that performs research on fasting in humans and he is the owner of TrueNorth Health Center and the president of the board of the TrueNorth Health Foundation. M.H. has co-authored three self-help books for the public to follow intermittent diets. All author proceeds are paid directly to the charity Prevent Breast Cancer (registered charity number 1109839) to fund breast cancer research. M.H. undertakes paid webinars for Nestlé Health Science and Oviva. All payments are made to Manchester University Foundation Trust. B.D.H. is a member of the advisory boards of Opsis Health and Lab Me Analytics, a consultant to Pfizer regarding risk scores (funds paid to Intermountain), and site PI of grants (not related to fasting) from the Patient-Centered Outcomes Research Institute, the NIH RECOVER initiative, and the Task Force for Global Health. J.L. offers consulting and expert activities to Medizinverlage Stuttgart; Ferring Arzneimittel GmbH; Repha GmbH; Dr. Willmar Schwabe. He receives honoraria as a speaker from Falk Foundation; Repha GmbH Biologische Arzneimittel; Dr. Willmar Schwabe; Galapagos Pharma, Takeda Pharmaceutical, Janssen Cilag, Dr. Pfleger Arzneimittel, Bristol-Myers Squibb GmbH, Bionorica, Luvos Just GmbH, Pfitzer Pharma GmbH and Enterosan Labordiagnostik. J.L. receives research funding from Falk Foundation, Dr. Willmar Schwabe, Repha GmbH Biologische Arzneimittel, TechLab. F.M. has equity interests in and is advisor of The Longevity Labs (TLL) and is a scientific co-founder of Samsara Therapeutics. F.M. is grateful to the Austrian Science Fund FWF (F3012, W1226, P31727, P37016, P 37278) and the Austrian Federal Ministry of Education, Science and Research as well as the University of Graz for grants “Unkonventionelle Forschung-InterFast and Fast4Health.” We acknowledge the support of the Field of Excellence BioHealth of NAWI Graz and the BioTechMed-Graz flagship project “EPIAge.” M.R.-W. is a member of the board of the German Medical Association for Fasting and Nutrition (ÄGHE). K.V. received author fees from Hachette Book Group for The Every Other Day Diet. R.d.C. is supported in part by the Intramural Research Program at the NIA, National Institutes of Health. V.L. has equity interest in L-Nutra Inc., a company that markets and sells the FMD. USC has licensed intellectual property to L-Nutra and as part of this license agreement, the University has the potential to receive royalty payments from L-Nutra. 100% of V.L.’s equity is assigned to the non-profit foundation Create Cures. S.P. is the author of the books “The Circadian Code” and “The Circadian Diabetes Code.” R.S. is member of the German Medical Association for Fasting and Nutrition (ÄGHE), president of National Association of Physicians for Natural Medicine (ZAEN), has received honoraries for conduct of clinical trials, consulting and lectures from Repha GmbH Biologische Arzneimittel, Langenhagen, Germany, Mediconomics GmbH, Hannover, Germany S.A. Vogel, Roggwil, Switzerland, Clinica Holistica Engiadina, Susch, Switzerland, Roleca Pharma GmbH, Hannover, Germany.

Figures

**Figure 1.. Flowchart of the recruitment process and participation in the study**

**Figure 2.. Overview of the consensus process for all terms**
CC, consensus conference. Gray field: term does not occur in this round; violet field: term that is not given its own definition but will be combined with another term in the next round; dark green: term on which no consensus was reached in final round, so last consensus reached is counted (exception: IER); ✔: final consensus in this round; ≈: ≥70% agreement, but changes required; ≈*: agreement in CC, but new assessment in round 4 required; Ø: not discussed in the CC or not discussed in detail due to time constraints; → and (→): <70% agreement; ✘: no consensus at the end of final round, last consensus reached is used; ✘**: exception: consensus from round 2 is used.

**Figure 3.. Classification of terminology**
All defined terms are listed here in distinct categories.

See this image and copyright information in PMC

References

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International consensus on fasting terminology

Affiliations

International consensus on fasting terminology

Authors

Affiliations

Abstract

Conflict of interest statement

Figures

References

MeSH terms

Grants and funding

LinkOut - more resources

Full Text Sources