Cited by 180Muscle metabolism and nutritionSports Performance and TrainingCardiovascular and exercise physiology

Pre-exercise carbohydrate and fat ingestion: effects on metabolism and performance

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Hargreaves, Mark, Hawley, John A, Jeukendrup, Asker·2004·Journal of Sports Sciences

Abstract

A key goal of pre-exercise nutritional strategies is to maximize carbohydrate stores, thereby minimizing the ergolytic effects of carbohydrate depletion. Increased dietary carbohydrate intake in the days before competition increases muscle glycogen levels and enhances exercise performance in endurance events lasting 90 min or more. Ingestion of carbohydrate 3-4 h before exercise increases liver and muscle glycogen and enhances subsequent endurance exercise performance. The effects of carbohydrate ingestion on blood glucose and free fatty acid concentrations and carbohydrate oxidation during exercise persist for at least 6 h. Although an increase in plasma insulin following carbohydrate ingestion in the hour before exercise inhibits lipolysis and liver glucose output, and can lead to transient hypoglycaemia during subsequent exercise in susceptible individuals, there is no convincing evidence that this is always associated with impaired exercise performance. However, individual experience should inform individual practice. Interventions to increase fat availability before exercise have been shown to reduce carbohydrate utilization during exercise, but do not appear to have ergogenic benefits.

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Registry

Crossref · 10.1080/0264041031000140536

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Authors
Hargreaves, M., Hawley, J. A., & Jeukendrup, A.
Affiliations
  • Deakin University (AU)
  • RMIT University (AU)
  • University of Birmingham (GB)
Venue
Journal of Sports Sciences
Published
2004-01
Volume
22
Issue
1
Pages
31-38
ISSN
  • 0264-0414 (ISSN-L)
  • 1466-447X
OpenAlex
W2150585142
Cited by
178
References
90
Citations by year
2026: 2 · 2025: 7 · 2024: 6 · 2023: 8 · 2022: 4 · 2021: 13 · 2020: 8 · 2019: 7 · 2018: 9 · 2017: 3 · 2016: 7 · 2015: 10 · 2014: 10 · 2013: 14 · 2012: 16
FWCI
1.58
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • Journal of Sports Sciences (publishedVersion)
  • PubMed (publishedVersion)
  • RMIT Research Repository (RMIT University Library) (submittedVersion)
  • Figshare (submittedVersion, cc-by)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
  • Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
  • Health Sciences › Medicine › Complementary and alternative medicine › Cardiovascular and exercise physiology
Keywords
pre-exercise nutrition, carbohydrate intake, dietary fat intake, muscle glycogen, liver glycogen, endurance exercise performance, carbohydrate oxidation, free fatty acids, blood glucose, plasma insulin, lipolysis, hypoglycemia, ergogenic aids
MeSH terms
Dietary Carbohydrates, Dietary Fats, Energy Metabolism, Glycogen, Humans, Nutritional Physiological Phenomena, Physical Endurance, Time Factors

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