The aim of this study was to examine the effects of a specific glycemic index (GI) diet on performance in competitive cyclists. Several studies have shown that different meals of varying glycemic indexes can affect performance, but no there are no studies that examine performance using long-term GI regulated diet. Twelve subjects (9 males, 3 females) were randomly assigned to either a control group or an experimental group. Subjects were tested using a 20-minute sub-max threshold test on a computrainer measuring average power. The control group had no changes in their diets, however the experimental group followed a specific GI diet regulating the timing, quality, and glycemic index of all foods consumed. Experimental subjects kept a detailed nutrition log of everything consumed for six to eight weeks, upon which they were re-tested. Nine subjects (7 males, 2 females) completed the study with results showing no statistically significant (p-value <.05) difference in power between the experimental and control groups. However, improvements in study design and testing techniques could potentially produce a significant difference in performance.
