Ketogenic Diet Benefits Body Composition and Well-being but Not Performance in a Pilot Case Study of New Zealand Endurance Athletes

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aut.relation.articlenumber22en_NZ
aut.relation.issue22en_NZ
aut.relation.journalJournal of the International Society of Sports Nutritionen_NZ
aut.relation.volume14en_NZ
aut.researcherZinn, Caryn
dc.contributor.authorZinn, Cen_NZ
dc.contributor.authorWood, Men_NZ
dc.contributor.authorWilliden, Men_NZ
dc.contributor.authorChatterton, Sen_NZ
dc.contributor.authorMaunder, Een_NZ
dc.date.accessioned2021-06-29T04:10:17Z
dc.date.available2021-06-29T04:10:17Z
dc.date.copyright2017en_NZ
dc.date.issued2017en_NZ
dc.description.abstractBackground: Low-carbohydrate, high-fat and ketogenic diets are increasingly adopted by athletes for body composition and sports performance enhancements. However, as yet, there is no consensus on their efficacy in improving performance. There is also no comprehensive literature on athletes' experiences while undertaking this diet. The purpose of this pilot work was two-fold: i. to examine the effects of a non-calorie controlled ketogenic diet on body composition and performance outcomes of endurance athletes, and ii. to evaluate the athletes' experiences of the ketogenic diet during the 10-week intervention. Methods: Using a case study design, five New Zealand endurance athletes (4 females, 1 male) underwent a 10-week ketogenic dietary intervention. Body composition (sum of 8 skinfolds), performance indicators (time to exhaustion, VO 2 max, peak power and ventilatory threshold), and gas exchange thresholds were measured at baseline and at 10 weeks. Mean change scores were calculated, and analysed using t-tests; Cohen's effect sizes and 90% confidence limits were applied to quantify change. Individual interviews conducted at 5 weeks and a focus group at 10 weeks assessed athletes' ketogenic diet experiences. Data was transcribed and analysed using thematic analysis. Results: All athletes increased their ability to utilise fat as a fuel source, including at higher exercise intensities. Mean body weight was reduced by 4 kg ± SD 3.1 (p = 0.046; effect size (ES):0.62), and sum of 8 skinfolds by 25.9 mm ± SD 6.9; ES: 1.27; p = 0.001). Mean time to exhaustion dropped by ~2 min (±SD 0.7; p = 0.004; ES: 0.53). Other performance outcomes showed mean reductions, with some increases or unchanged results in two individuals (VO2 Max: -1.69 ml.kg.min ± SD 3.4 (p = 0.63); peak power: -18 W ± SD 16.4 (p = 0.07), and VT2: -6 W ± SD 44.5 (p = 0.77). Athletes reported experiencing reduced energy levels initially, followed by a return of high levels thereafter, especially during exercise, but an inability to easily undertake high intense bouts. Each athlete reported experiencing enhanced well-being, included improved recovery, improvements in skin conditions and reduced inflammation. Conclusions: Despite performance decrements and some negative experiences, athletes were keen to pursue a modified low-carbohydrate, high-fat eating style moving forward due to the unexpected health benefits they experienced. Trial registration: ACTRN: ACTRN12617000613303. Registered 28 April 2017, retrospectively registered.en_NZ
dc.identifier.citationJournal of the International Society of Sports Nutrition, 14, 22 (2017). https://doi.org/10.1186/s12970-017-0180-0
dc.identifier.doi10.1186/s12970-017-0180-0en_NZ
dc.identifier.issn1550-2783en_NZ
dc.identifier.urihttps://hdl.handle.net/10292/14312
dc.publisherBioMed Central
dc.relation.urihttps://jissn.biomedcentral.com/articles/10.1186/s12970-017-0180-0en_NZ
dc.rights© The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
dc.rights.accessrightsOpenAccessen_NZ
dc.subjectLow-carbohydrate; High-fat; LCHF; Endurance athletes; Well-being; Performance
dc.titleKetogenic Diet Benefits Body Composition and Well-being but Not Performance in a Pilot Case Study of New Zealand Endurance Athletesen_NZ
dc.typeJournal Article
pubs.elements-id285579
pubs.organisational-data/AUT
pubs.organisational-data/AUT/Faculty of Health & Environmental Science
pubs.organisational-data/AUT/Faculty of Health & Environmental Science/School of Sport & Recreation
pubs.organisational-data/AUT/Faculty of Health & Environmental Science/School of Sport & Recreation/Physical Activity, Nutrition & the Outdoors Department
pubs.organisational-data/AUT/Faculty of Health & Environmental Science/School of Sport & Recreation/Sport & Exercise Science Department
pubs.organisational-data/AUT/Faculty of Health & Environmental Science/School of Sport & Recreation/Sports Performance Research Institute New Zealand
pubs.organisational-data/AUT/Faculty of Health & Environmental Science/School of Sport & Recreation/Sports Performance Research Institute New Zealand/Human Potential Research Group
pubs.organisational-data/AUT/Faculty of Health & Environmental Science/School of Sport & Recreation/Sports Performance Research Institute New Zealand/Sports Physiology & Nutrition Research Group
pubs.organisational-data/AUT/PBRF
pubs.organisational-data/AUT/PBRF/PBRF Health and Environmental Sciences
pubs.organisational-data/AUT/PBRF/PBRF Health and Environmental Sciences/HS Sports & Recreation 2018 PBRF
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