Effect of the glycemic index of pre-exercise snack bars on substrate utilization during subsequent exercise.
ABSTRACT Abstract Purpose: To investigate the effect of the glycemic index (GI) of pre-exercise snack bars on substrate utilization during subsequent moderate intensity exercise. Methods: Fourteen male participants (Age: 27 ± 5 yr; BMI: 22.5 ± 2.7 kg m(-2); [Formula: see text]: 48.7 ± 6.1 mL kg(-1 )min(-1)) completed two trials in a randomized and counterbalanced crossover design. Two iso-caloric snack bars with different GI values (20, LGI versus 68, HGI) were provided to the participants. Ninety minutes later, all participants completed 45 minutes of ergometer cycling at 65% [Formula: see text]. Substrate utilization was measured using indirect calorimetry. Results: During exercise, higher fat oxidation and lower carbohydrate (CHO) oxidation were observed in the LGI trial (LGI versus HGI: CHO, 87.3 ± 20.1 versus 99.2 ± 19.0 g, p < 0.05; Fat, 15.0 ± 5.8 versus 9.7 ± 7.0 g, p < 0.05). Conclusion: Compared with an iso-caloric HGI snack bar, pre-exercise LGI snack bar consumption may facilitate a shift of substrate utilization from CHO to fat during subsequent moderate intensity exercise.
- Medicine and science in sports 02/1973; 5(2):90-3.
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ABSTRACT: The determine the effect of different foods on the blood glucose, 62 commonly eaten foods and sugars were fed individually to groups of 5 to 10 healthy fasting volunteers. Blood glucose levels were measured over 2 h, and expressed as a percentage of the area under the glucose response curve when the same amount of carbohydrate was taken as glucose. The largest rises were seen with vegetables (70 +/- 5%), followed by breakfast cereals (65 +/- 5%), cereals and biscuits (60 +/- 3%), fruit (50 +/- 5%), dairy products (35 +/- 1%), and dried legumes (31 +/- 3%). A significant negative relationship was seen between fat (p less than 0.01) and protein (p less than 0.001) and postprandial glucose rise but not with fiber or sugar content.American Journal of Clinical Nutrition 04/1981; 34(3):362-6. · 6.50 Impact Factor
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ABSTRACT: Subjects rated the perceived temperature and hedonic values of four samples of drinking water (5 degrees, 16 degrees, 22 degrees, 38 degrees C) after exercise and on a control day. Ad lib drinking of any of the four samples was permitted for 20 minutes after exercise and intake was measured. Subjects completed questionnaires pertaining to their subjective states. Sensory thermal neutral water was found to be close to 22 degrees C which was also judged to be affectively neutral. Subjects rated 16 degrees C water higher on the hedonic scale after exercise than they did on a control day, despite the fact that no change in the perception of this temperature was observed. Responses to the symptoms questionnaire showed a marked effect of exercise on the perception of thirst, sweating, body warmth and dryness in the mouth. Sensations of stomach fullness could not account for the incomplete rehydration of most subjects in the time allotted. It was suggested that a rapid reduction in symptoms which initiate drinking was responsible for drinking termination. The role of water temperature in the reduction of thirst symptoms was discussed.Physiology & Behavior 06/1984; 32(5):851-5. · 3.16 Impact Factor