Post-exercise Ingestion of Carbohydrate, Protein and Water: A Systematic Review and Meta-analysis for Effects on Subsequent Athletic Performance

Abstract

Background: Athletes may complete consecutive exercise sessions with limited recovery time between bouts (e.g. ≤ 4 h). Nutritional strategies that optimise post-exercise recovery in these situations are therefore important.

Objective: This two-part review investigated the effect of consuming carbohydrate (CHO) and protein with water (W) following exercise on subsequent athletic (endurance/anaerobic exercise) performance.

Data sources: Studies were identified by searching the online databases SPORTDiscus, PubMed, Web of Science and Scopus.

Study eligibility criteria and interventions: Investigations that measured endurance performance (≥ 5 min duration) ≤ 4 h after a standardised exercise bout (any type) under the following control vs. intervention conditions were included: Part 1: W vs. CHO ingested with an equal volume of W (CHO + W); and, Part 2: CHO + W vs. protein (PRO) ingested with CHO and an equal volume of W (PRO + CHO + W), where CHO or energy intake was matched.

Study appraisal and synthesis methods: Publications were examined for bias using the Rosendal scale. Random-effects meta-analyses and meta-regression analyses were conducted to evaluate intervention efficacy.

Results: The quality assessment yielded a Rosendal score of 63 ± 9% (mean ± standard deviation). Part 1: 45 trials (n = 486) were reviewed. Ingesting CHO + W (102 ± 50 g CHO; 0.8 ± 0.6 g CHO kg^-1 h^-1) improved exercise performance compared with W (1.6 ± 0.7 L); %_Δ mean power output = 4.0, 95% confidence interval 3.2-4.7 (I ² = 43.9). Improvement was attenuated when participants were 'Fed' (a meal 2-4 h prior to the initial bout) as opposed to 'Fasted' (p = 0.012). Part 2: 13 trials (n = 125) were reviewed. Ingesting PRO + CHO + W (35 ± 26 g PRO; 0.5 ± 0.4 g PRO kg^-1) did not affect exercise performance compared with CHO + W (115 ± 61 g CHO; 0.6 ± 0.3 g CHO·kg body mass^-1 h^-1; 1.2 ± 0.6 L); %_Δ mean power output = 0.5, 95% confidence interval - 0.5 to 1.6 (I ² = 72.9).

Conclusions: Athletes with limited time for recovery between consecutive exercise sessions should prioritise CHO and fluid ingestion to enhance subsequent athletic performance. PROSPERO REGISTRATION NUMBER: CRD42016046807.