Glycemic and insulinemic response to selected snack bars in trained versus sedentary individuals

The purpose of this study was to determine whether glycemic index (GI) is influenced by training state. Participants were tested in a randomized order: twice with a reference solution containing 50 g glucose and once each with 2 commercially available snack bars (Griffin's Fruitli bar and Peak Fuel's Summit bar) containing 50 g available carbohydrate. Eleven of the participants (6 men and 5 women, M + or - SD age 20.8 + or - 2.0 yr) were endurance trained (ET; VO(2max) 57.5 + or - 8.4 ml x kg(-1) x min(-1) ), and 9 participants (2 men and 7 women, M + or - SD age 22.4 + or - 1.8 yr) were sedentary (SE; VO(2max) 43.7 + or - 9.1 ml x kg(-1) x min(-1) ). After an overnight fast, participants consumed either the glucose solution or snack bar, with blood samples taken before eating and at 15, 30, 45, 60, 90, and 120 min after eating began. The mean incremental area under the curve (IAUC) of the glucose reference was 31% lower (95% CI 3-52%, p = .03), and the Fruitli bar 38% lower (95% CI 0-61%, p = .05) in ET than in SE participants. There was a trend for the IAUC for the Summit bar to be 35% lower in ET than in SE participants (95% CI -7% to 61% p = .09). There was no significant interaction between training state and test food. The GIs of the Fruitli and Summit bars was not significantly different between ET and SE participants (p = .65 and .54, respectively). ET participants had a lower glycemic response than SE participants; however, training state did not influence GI.