PMID- 27677914
OWN - NLM
STAT- MEDLINE
DCOM- 20180618
LR  - 20181202
IS  - 1179-2035 (Electronic)
IS  - 0112-1642 (Linking)
VI  - 47
IP  - 6
DP  - 2017 Jun
TI  - Effect of Glycemic Index of a Pre-exercise Meal on Endurance Exercise 
      Performance: A Systematic Review and Meta-analysis.
PG  - 1087-1101
LID - 10.1007/s40279-016-0632-8 [doi]
AB  - BACKGROUND: Low glycemic index (GI) pre-exercise meals may enhance endurance 
      performance by maintaining euglycemia and altering fuel utilization. However, 
      evidence for performance benefits is equivocal. OBJECTIVE: To evaluate the effect 
      of a low GI (LGI) versus a high GI (HGI) pre-exercise meal on endurance 
      performance using meta-analyses. METHODS: Data sources included MEDLINE, 
      SPORTDiscus, AUSPORT, AusportMed, Web of Science, and Scopus. Eligibility 
      criteria were randomized, crossover trials with an endurance exercise (>/=60 min) 
      component, e.g., time trial (TT), time to exhaustion (TTE) test, or submaximal 
      bout followed by TT or TTE. Participants were healthy, active individuals aged 
      >/=16 years. Interventions included a LGI (</=55) and HGI (>/=70) meal ingested 
      30-240 min before exercise. Study quality was assessed using an adapted version 
      of the validated Downs and Black tool. Effect size (ES) and 95 % confidence 
      interval were calculated for each study and pooled according to performance test 
      type and whether exogenous carbohydrate (CHO) was given during exercise. 
      Potential effect modifiers including exercise duration, pre-exercise meal timing, 
      glycemic load (GL), and fitness were assessed using meta-regression. RESULTS: The 
      search netted 3431 citations with 19 studies eligible for inclusion (totaling 188 
      participants; 91 % male; VO(2max): >50 ml/kg/min). Meals with 0.18-2 g CHO/kg 
      body mass, and a mean GI and glycemic load of 82 (GL: 72) and 35 (GL: 32) for HGI 
      and LGI, respectively, were given between 30 and 210 min before exercise. All 
      test types without CHO ingestion during exercise showed slightly improved 
      performance with LGI, but no significant pooled effects were observed (ES: -0.17 
      to -0.36; p > 0.05). Studies where exogenous CHO was ingested during exercise 
      showed conflicting results (ES: -0.67 to 0.11; p = 0.04 to 0.94). No significant 
      relationship was observed with any of the effect modifiers (p > 0.05). No 
      consistent metabolic responses (glucose, insulin, lactate, respiratory exchange 
      ratio) during exercise were observed with either meal type. LIMITATIONS: There 
      were small numbers of studies within each exercise testing protocol and limited 
      statistical power within studies. Pre-exercise meal timing, GL, meal composition 
      and participant fitness varied across studies, limiting the capacity to assess 
      the influence of these factors on study outcomes. CONCLUSION: There was no clear 
      benefit of consuming a LGI pre-exercise meal for endurance performance regardless 
      of carbohydrate ingestion during exercise.
FAU - Burdon, Catriona A
AU  - Burdon CA
AD  - Discipline of Exercise and Sport Science, Faculty of Health Sciences, The 
      University of Sydney, 75 East Street, Lidcombe, Sydney, NSW, 2141, Australia.
AD  - School of Medicine, University of Wollongong, Wollongong, NSW, Australia.
FAU - Spronk, Inge
AU  - Spronk I
AD  - Wageningen University, Wageningen, The Netherlands.
FAU - Cheng, Hoi Lun
AU  - Cheng HL
AD  - Discipline of Exercise and Sport Science, Faculty of Health Sciences, The 
      University of Sydney, 75 East Street, Lidcombe, Sydney, NSW, 2141, Australia.
AD  - Academic Department of Adolescent Medicine, The Children's Hospital at Westmead, 
      Westmead, Sydney, NSW, Australia.
AD  - Discipline of Child and Adolescent Health, Sydney Medical School, The University 
      of Sydney, Westmead, Sydney, NSW, Australia.
FAU - O'Connor, Helen T
AU  - O'Connor HT
AD  - Discipline of Exercise and Sport Science, Faculty of Health Sciences, The 
      University of Sydney, 75 East Street, Lidcombe, Sydney, NSW, 2141, Australia. 
      helen.oconnor@sydney.edu.au.
AD  - Charles Perkins Centre, The University of Sydney, Camperdown, Sydney, NSW, 
      Australia. helen.oconnor@sydney.edu.au.
LA  - eng
PT  - Journal Article
PT  - Meta-Analysis
PT  - Review
PT  - Systematic Review
PL  - New Zealand
TA  - Sports Med
JT  - Sports medicine (Auckland, N.Z.)
JID - 8412297
RN  - 0 (Blood Glucose)
RN  - 0 (Dietary Carbohydrates)
RN  - 0 (Insulin)
SB  - IM
MH  - Blood Glucose/metabolism
MH  - *Dietary Carbohydrates
MH  - *Exercise
MH  - Exercise Test
MH  - *Glycemic Index
MH  - Humans
MH  - Insulin
MH  - Male
MH  - Meals
MH  - Physical Endurance/*physiology
EDAT- 2016/09/30 06:00
MHDA- 2018/06/19 06:00
CRDT- 2016/09/29 06:00
PHST- 2016/09/30 06:00 [pubmed]
PHST- 2018/06/19 06:00 [medline]
PHST- 2016/09/29 06:00 [entrez]
AID - 10.1007/s40279-016-0632-8 [pii]
AID - 10.1007/s40279-016-0632-8 [doi]
PST - ppublish
SO  - Sports Med. 2017 Jun;47(6):1087-1101. doi: 10.1007/s40279-016-0632-8.