Oxidation of Solid versus Liquid Carbohydrate Sources during Exercise.

B Pfeiffer, T Stellingwerff, E Zaltas, Asker Jeukendrup

Research output: Contribution to journalArticle

51 Citations (Scopus)


The ingestion of carbohydrate (CHO) solutions has been shown to increase CHO oxidation and improve endurance performance. However, the majority of studies have investigated CHO in solution and sporting practice includes ingestion of CHO in solid (e.g. energy bars) as well as liquid form. It remains unknown whether CHO in solid form is as effectively oxidized as compared to CHO solutions. PURPOSE:: To investigate exogenous CHO oxidation from CHO provided in either solid (BAR) or solution (DRINK) form during cycling. METHODS:: Eight well trained subjects (31+/-7 yrs; 73+/-5 kg; 1.79+/-0.05 m; VO2max: 69+/-6 ml/kg/min) cycled at 58+/-4% VO2max for 180 min while receiving one of the following three treatments in randomized order: BAR plus water, DRINK, or water. The BAR and DRINK delivered glucose+fructose (GLU+FRC) in a ratio of 2:1 at a rate of 1.55 g/min and fluid intake was matched between treatments. RESULTS:: During the final 2 h of exercise overall mean exogenous CHO oxidation rate was -0.11 g/min lower in BAR (95% confidence interval: -0.27 to 0.05 g/min; p=0.19) relative to DRINK; exogenous CHO oxidation rates were 15% lower in BAR (p1g/min). The GLU+FRC mix ingested in form of a solid BAR resulted in similar average and peak exogenous CHO oxidation rates and showed similar oxidation efficiencies as a DRINK. These findings suggest that CHO from a solid BAR is effectively oxidized during exercise and can be a practical form of supplementation alongside other forms of CHO.
Original languageEnglish
JournalMedicine and Science in Sports and Exercise
Publication statusPublished - 19 Mar 2010




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