Previous investigations have reported that soluble fiber reduces the plasma glucose and insulin changes after an oral glucose load. To improve the payability of a soluble-fiber feeding, this study addressed how a combined, soluble fiber (delivered in capsule form) and a preexercise CHO feeding would affect metabolic responses during exercise. On 3 different days, participants ingested a placebo (CON), 75 g liquid CHO (GLU), or 75 g liquid CHO with 14.5 g encapsulated guar gum (FIB) 45 min before cycling for 60 min at 70% VO2peak. Peak concentrations of plasma glucose and insulin were similar and significantly greater than CON preexercise (p < .05). Similarities in carbohydrate reliance were observed in GLU and FIB. Muscle glycogen use did not differ significantly among trials. These results demonstrate that encapsulated soluble fiber delivered with a liquid CHO feeding does not affect plasma glucose, insulin, or muscle glycogen utilization during exercise.
Allen C. Parcell is now with the Human Performance Research Center in the Department of Physical Education at Brigham Young University, 212 Richards Building, Provo, UT 84602. Melinda L. Ray, Kristine A. Moss, Rick L. Sharp, and Douglas S. King are with the Exercise Physiology and Biochemistry Laboratory in the Department of Health and Human Performance at Iowa State University, Ames, IA 50011. Timothy M. Ruden is now with the Human Performance Laboratory at Weber State University, 2801 University Cir., Ogden, UT 84408-2801.