Evidence map›Paper›PMID 32497061›Full record

Trial reportPloS one2020

Crisis of confidence averted: Impairment of exercise economy and performance in elite race walkers by ketogenic low carbohydrate, high fat (LCHF) diet is reproducible.

Louise M Burke, Avish P Sharma, Ida A Heikura, Sara F Forbes, Melissa Holloway, Alannah K A McKay, Julia L Bone, Jill J Leckey, Marijke Welvaert, Megan L Ross

Erratum issuedOpen access · goldAbstract readClinical Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in PloS one, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. Cited by 57 papers, 6 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
57citing papers in PubMed, 6 pooled it
8.5field-weighted citation impact, top 2% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

57 citing papers in PubMed, 6 syntheses or guidelines pooled it, 95 citations in OpenAlex.

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  11. Divergent Changes in Peak Fat Oxidation and FatScandinavian journal of medicine & science in sports · 2025
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  17. Effect of low- and high-carbohydrate diets on swimming economy: a crossover study.Journal of the International Society of Sports Nutrition · 2020
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  20. Does a low-carbohydrate diet impede endurance sports performance? Yes.The American journal of clinical nutrition · 2026
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4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

10 authors at 3 institutions in 1 country.

Louise M BurkeAustralian Institute of Sport, Canberra, Australia.ORCID 0000-0001-8866-5637
Avish P SharmaAustralian Institute of Sport, Canberra, Australia.
Ida A HeikuraAustralian Institute of Sport, Canberra, Australia.
Sara F ForbesAustralian Institute of Sport, Canberra, Australia.
Melissa HollowayAustralian Institute of Sport, Canberra, Australia.
Alannah K A McKayAustralian Institute of Sport, Canberra, Australia.
Julia L BoneAustralian Institute of Sport, Canberra, Australia.
Jill J LeckeyMary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia.
Marijke WelvaertAustralian Institute of Sport, Canberra, Australia.
Megan L RossAustralian Institute of Sport, Canberra, Australia.
Australian Sports Commission · AUAustralian Catholic University · AUGriffith University · AU

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

introductionWe repeated our study of intensified training on a ketogenic low-carbohydrate (CHO), high-fat diet (LCHF) in world-class endurance athletes, with further investigation of a "carryover" effect on performance after restoring CHO availability in comparison to high or periodised CHO diets.

methodsAfter Baseline testing (10,000 m IAAF-sanctioned race, aerobic capacity and submaximal walking economy) elite male and female race walkers undertook 25 d supervised training and repeat testing (Adapt) on energy-matched diets: High CHO availability (8.6 g∙kg-1∙d-1 CHO, 2.1 g∙kg-1∙d-1 protein; 1.2 g∙kg-1∙d-1 fat) including CHO before/during/after workouts (HCHO, n = 8): similar macronutrient intake periodised within/between days to manipulate low and high CHO availability at various workouts (PCHO, n = 8); and LCHF (<50 g∙d-1 CHO; 78% energy as fat; 2.1 g∙kg-1∙d-1 protein; n = 10). After Adapt, all athletes resumed HCHO for 2.5 wk before a cohort (n = 19) completed a 20 km race.

resultsAll groups increased VO2peak (ml∙kg-1∙min-1) at Adapt (p = 0.02, 95%CI: [0.35-2.74]). LCHF markedly increased whole-body fat oxidation (from 0.6 g∙min-1 to 1.3 g∙min-1), but also the oxygen cost of walking at race-relevant velocities. Differences in 10,000 m performance were clear and meaningful: HCHO improved by 4.8% or 134 s (95% CI: [207 to 62 s]; p < 0.001), with a trend for a faster time (2.2%, 61 s [-18 to +144 s]; p = 0.09) in PCHO. LCHF were slower by 2.3%, -86 s ([-18 to -144 s]; p < 0.001), with no evidence of superior "rebound" performance over 20 km after 2.5 wk of HCHO restoration and taper.

conclusionOur previous findings of impaired exercise economy and performance of sustained high-intensity race walking following keto-adaptation in elite competitors were repeated. Furthermore, there was no detectable benefit from undertaking an LCHF intervention as a periodised strategy before a 2.5-wk race preparation/taper with high CHO availability.

trial registrationAustralia New Zealand Clinical Trial Registry: ACTRN12619000794101.

Indexed as

Athletic PerformanceDiet, High-FatDiet, KetogenicPhysical Conditioning, HumanWalkingAdaptation, PhysiologicalAthletesFemaleHumansMalePhysical Endurance

Identifiers

PMID32497061
PMCPMC7272074
OpenAlexW3033469141

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.