In our study an initial click here increase of glucose was observed and then plateaued whereas insulin continued to increase up to 30 minutes following the ingestion of foods. The same glucose and insulin response prior to exercise was seen selleck kinase inhibitor in De Marco et al. study when the same amount of carbohydrates was ingested [17]. This response of glucose and insulin is common since the initial increase in glucose constitutes the main stimulus for the delayed insulin increase. Several studies attempted

to alter the carbohydrate composition of a meal prior to exercise in an effort to improve performance. A number of those studies show no improvement in exercise performance [19, 22, 31–33]. Febbraio et al. [19] utilized a similar design with the one employed in this study and

found no significant differences in exercise performance. Subjects received low and high glycemic foods (1.0 g. kg-1 of body weight) 30 min prior to a 120-min submaximal exercise bout that was followed by a 30 min time trial. Total work performed during the time trial was similar between the LGI, the HGI and the control condition. These results were evident despite the fact that carbohydrate MLN2238 supplier oxidation was greater during the HGI condition. No significant differences in exercise performance were noted in two other studies by the same group [31, 32] when subjects received LGI and HGI foods (1.0 g. kg-1 of body mass) 45 min prior to submaximal exercise that was followed again by a time trial. Although

differences in glucose and insulin levels were reported following consumption of the LGI and HGI prior to exercise, there were no apparent differences in the blood metabolites during the steady state exercise. Thomas et al. [33] used four meals with different glycemic index foods (30, 36, 73 and 100) that each provided 1.0 g. kg-1 of body weight. selleck chemical The meal was consumed 1 h prior to cycling to exhaustion at 65-70% of VO2max. The results showed no significant differences in time to exhaustion between trials. No enhancement in exercise performance was found when low and high glycemic index foods were provided 3 h prior to exercise even though there was a relative shift in substrate utilization from carbohydrate to fat following the LGI meal [22]. As far as exercise performance is concerned, results from the present study coincide with those of earlier reports suggesting that although pre-exercise GI manipulation affects pre-exercise glucose and insulin levels, it does not presumably influence the rate of muscle glycogen utilization or exercise performance. Differences in glucose levels and carbohydrate and fat oxidation during steady state exercise could influence exercise performance during a subsequent short and intense exercise.