{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,9]],"date-time":"2026-11-09T22:03:56Z","timestamp":1794261836651,"version":"4.9.0"},"reference-count":44,"publisher":"Cambridge University Press (CUP)","issue":"7","license":[{"start":{"date-parts":[[2025,9,18]],"date-time":"2025-09-18T00:00:00Z","timestamp":1758153600000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["cambridge.org"],"crossmark-restriction":true},"short-container-title":["Br J Nutr"],"published-print":{"date-parts":[[2025,10,14]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    The purpose of this study was to confirm reduced training metrics previously associated with a ketogenic low-carbohydrate (CHO) high-fat diet (LCHF) and investigate their attenuation with caffeine supplementation. At baseline,\n                    <jats:italic>n<\/jats:italic>\n                    21 elite race-walkers followed a high CHO availability (HCHO) diet and performed a tempo hill session (14 km with a 450 m elevation gain). Athletes were then assigned to either the HCHO or LCHF in a parallel groups design for 3 weeks, where the 14 km tempo hill session was repeated each week. On weeks 2 and 3, in a randomised crossover allocation, all participants received 3 mg\/kg caffeine or placebo (gum), 20 min before the session. Race-walking speed, heart rate, ratings of perceived exertion, blood metabolites and Stroop word-colour test metrics were collected. Although LCHF athletes walked faster at baseline compared with HCHO (\n                    <jats:italic>P<\/jats:italic>\n                    = 0\u00b7049), the HCHO group improved by week 2 (\n                    <jats:italic>P<\/jats:italic>\n                    = 0\u00b7009) and week 3 (\n                    <jats:italic>P<\/jats:italic>\n                    = 0\u00b7007), whereas the LCHF group was significantly slower in Week 1 (\n                    <jats:italic>P<\/jats:italic>\n                    &lt; 0\u00b7001) and Week 2 (\n                    <jats:italic>P<\/jats:italic>\n                    = 0\u00b7026) compared with baseline. During the 14 km hill session, within-group analysis shows that athletes walked significantly faster (\n                    <jats:italic>P<\/jats:italic>\n                    = 0\u00b7010) and at a higher percentage of vVO\n                    <jats:sub>2<\/jats:sub>\n                    max (\n                    <jats:italic>P<\/jats:italic>\n                    = 0\u00b7007) when using caffeine compared with a placebo. Between-group differences remained present, with HCHO athletes walking at a higher percentage of vVO\n                    <jats:sub>2<\/jats:sub>\n                    max than those adhering to the LCHF diet (\n                    <jats:italic>P<\/jats:italic>\n                    = 0\u00b7035). No interaction between supplement treatment and dietary group occurred (\n                    <jats:italic>P<\/jats:italic>\n                    = 0\u00b7640). Caffeine supplementation partially reversed the performance impairment associated with an LCHF diet, but training quality remained lower than the combination of caffeine and high CHO availability.\n                  <\/jats:p>","DOI":"10.1017\/s0007114525105084","type":"journal-article","created":{"date-parts":[[2025,9,18]],"date-time":"2025-09-18T10:38:01Z","timestamp":1758191881000},"page":"578-588","update-policy":"https:\/\/doi.org\/10.1017\/policypage","source":"Crossref","is-referenced-by-count":3,"title":["Caffeine enhances performance regardless of fueling strategy; however, high carbohydrate availability is associated with improved training speeds compared with ketogenic diet"],"prefix":"10.1017","volume":"134","author":[{"given":"Louise M.","family":"Burke","sequence":"first","affiliation":[{"name":"Mary MacKillop Institute for Health Research, Australian Catholic University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lucy","family":"Merrell","sequence":"additional","affiliation":[{"name":"University of Bath"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ida A.","family":"Heikura","sequence":"additional","affiliation":[{"name":"Mary MacKillop Institute for Health Research, Australian Catholic University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rita","family":"Civil","sequence":"additional","affiliation":[{"name":"University of Birmingham"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Avish P.","family":"Sharma","sequence":"additional","affiliation":[{"name":"Victorian Institute of Sport"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jill J.","family":"Leckey","sequence":"additional","affiliation":[{"name":"South Australian Sports Institute"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4184-3886","authenticated-orcid":false,"given":"Alannah K. A.","family":"McKay","sequence":"additional","affiliation":[{"name":"Mary MacKillop Institute for Health Research, Australian Catholic University"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"56","published-online":{"date-parts":[[2025,9,18]]},"reference":[{"key":"S0007114525105084_ref43","doi-asserted-by":"publisher","DOI":"10.1249\/MSS.0000000000001700"},{"key":"S0007114525105084_ref19","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.299.6694.313"},{"key":"S0007114525105084_ref26","doi-asserted-by":"publisher","DOI":"10.1016\/j.metabol.2017.10.010"},{"key":"S0007114525105084_ref38","doi-asserted-by":"publisher","DOI":"10.1249\/MSS.0b013e31817bb8b7"},{"key":"S0007114525105084_ref9","doi-asserted-by":"publisher","DOI":"10.1123\/ijsnem.16.5.545"},{"key":"S0007114525105084_ref32","doi-asserted-by":"publisher","DOI":"10.1080\/17461391.2014.971880"},{"key":"S0007114525105084_ref8","doi-asserted-by":"publisher","DOI":"10.1123\/ijsnem.2018-0020"},{"key":"S0007114525105084_ref36","doi-asserted-by":"publisher","DOI":"10.1016\/j.neubiorev.2016.09.001"},{"key":"S0007114525105084_ref28","doi-asserted-by":"publisher","DOI":"10.1249\/MSS.0000000000002517"},{"key":"S0007114525105084_ref24","doi-asserted-by":"publisher","DOI":"10.3390\/nu14050953"},{"key":"S0007114525105084_ref4","doi-asserted-by":"publisher","DOI":"10.1249\/MSS.0000000000002008"},{"key":"S0007114525105084_ref41","doi-asserted-by":"publisher","DOI":"10.3389\/fnut.2020.00020"},{"key":"S0007114525105084_ref34","doi-asserted-by":"publisher","DOI":"10.1249\/MSS.0b013e31828af183"},{"key":"S0007114525105084_ref27","first-page":"738","article-title":"High rates of fat oxidation induced by a low-carbohydrate, high-fat diet, do not impair 5-km running performance in competitive recreational athletes","volume":"18","author":"Prins","year":"2019","journal-title":"J Sports Sci Med"},{"key":"S0007114525105084_ref30","doi-asserted-by":"publisher","DOI":"10.1123\/ijsnem.2018-0289"},{"key":"S0007114525105084_ref3","doi-asserted-by":"publisher","DOI":"10.1002\/9780470059593.ch8"},{"key":"S0007114525105084_ref1","doi-asserted-by":"publisher","DOI":"10.1123\/ijspp.2022-0351"},{"key":"S0007114525105084_ref42","unstructured":"42. 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Published by Cambridge University Press on behalf of The Nutrition Society","name":"copyright","label":"Copyright","group":{"name":"copyright_and_licensing","label":"Copyright and Licensing"}},{"value":"This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (https:\/\/creativecommons.org\/licenses\/by\/4.0\/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.","name":"license","label":"License","group":{"name":"copyright_and_licensing","label":"Copyright and Licensing"}},{"value":"This content has been made available to all.","name":"free","label":"Free to read"}]}}