Carbohydrate supplementation optimises athletic performance, but the metabolic and performance impacts of commercial products/compositions are underexplored. We compared the efficacy of three commercial carbohydrate supplements: a glucose-fructose bar (GF-Bar), a glucose-fructose hydrogel (GF-Gel) and a maltodextrin-based gel (MD-Gel). Antegrade venous blood samples for glucose and insulin were measured alongside substrate utilisation in healthy Tier 2 athletes after ingesting 45 g of carbohydrates from the GF-Bar, GF-Gel and MD-Gel during a modified 1-h oral glucose tolerance test (OGTT). Additionally, the effect of supplementation on high-intensity interval exercise was evaluated during repeated maximal sprint performance. During the OGTT, the GF-Bar elicited greater total carbohydrate oxidation than MD-Gel (24.6 ± 7.4 g vs. 17.8 ± 8.6 g, P = 0.038) but not GF-Gel (20.1 ± 6.4 g, P > 0.05). Carbohydrate oxidation per minute varied over time (P < 0.001) and between products (P = 0.043), with GF-Bar (0.27 ± 0.05 g min-1) showing higher oxidation than GF-Gel (0.21 ± 0.05 g min-1) and MD-Gel (0.19 ± 0.06 g min-1). No differences were observed in glucose peak, time to peak glucose or insulin concentration (P > 0.05). Peak power (P = 0.011), mean power (P < 0.001) and total work varied across sprints (P < 0.001) but not between products (P > 0.05). Perceived exertion and gastrointestinal discomfort were similar between products (P > 0.05). Despite differences in carbohydrate oxidation during the OGTT, the GF-Bar, GF-Gel and MD-Gel displayed similar metabolic and sprint performance outcomes, suggesting that, within this study, carbohydrate formulation did not impact short-duration maximal exercise. Highlights - What is the central question of this study? Carbohydrate supplementation optimises athletic performance, but the metabolic and performance impacts of commercial products/compositions are underexplored: what is the efficacy of a glucose-fructose bar, a glucose-fructose hydrogel and a maltodextrin-based gel? - What is the main finding and its importance? In Tier 2 athletes, a glucose-fructose bar led to significantly greater total carbohydrate oxidation than a maltodextrin gel during a 1-h OGTT but not compared to a glucose-fructose hydrogel. No significant effects were observed on blood glucose, insulin, sprint performance or gastrointestinal comfort. All supplements produced similar outcomes during repeated high-intensity sprints, suggesting that carbohydrate formulation did not influence short-duration maximal exercise performance in this context.
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