Effect of Glycemic Index on Physical Capacity in Runners

NCT ID: NCT03062527

Last Updated: 2017-02-23

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 36 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2015-01-31
• Study Completion Date: 2015-05-01

Brief Summary

The purpose of the present study was to assess the influence of low vs moderate glycemic index of a 3-week diet on aerobic capacity, endurance performance and body mass and composition in endurance-trained athletes in a randomized, controlled crossover trial.

Detailed Description

The effect of glycemic index of pre-exercise meal on endurance capacity and performance has been widely investigated. However, little is known about the adaptations to longer dietary interventions with different glycemic index and their influence on aerobic capacity and body composition in runners. Therefore, the purpose of this study was the assessment of the influence of low GI vs moderate GI of a 3-week diet on aerobic capacity, endurance performance and body mass and composition in endurance-trained athletes in a randomised, controlled crossover trial.

Conditions

Nutrition; Sport; Glycemic Index; Physical Capacity

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

Low Glycemic Index Diet

Group consuming low glycemic index diet. Calculated glycemic index of daily diet was lower than 40. Carbohydrate- containing foods included whole rye bread, pumpernickel bread, whole oats, wheat brans, brown rice, buckwheat, vegetables (besides corn, cooked carrots, potatoes and pumpkin) and fruit such as apples, pears, grapefruits, tangerines, prunes, dried apricots and unripe bananas.

Interventions:

The experimental procedure for each participant included a 3-week low glycemic index diet. Between the 3-week low and moderate glycemic index diets or a moderate and low glycemic index treatment, a 14-day washout period was introduced.

Group Type: EXPERIMENTAL

Dietary Intervention: Low vs. moderate glycemic index

Intervention Type: OTHER

Moderate Glycemic Index Diet

Group consuming moderate glycemic index diet. Calculated glycemic index of diet was higher than 60. Carbohydrate- containing foods included wheat bread, wheat rolls, potatoes, instant oats, cornflakes, white rice, millet, boiled carrots and fruit (ripe bananas, grapes, raisins, dates, cranberry, honey and high sugar jams)

Interventions:

The experimental procedure for each participant included a 3-week moderate glycemic index diet. Between the 3-week low and moderate glycemic index diets or a moderate and low glycemic index treatment, a 14-day washout period was introduced.

Group Type: EXPERIMENTAL

Dietary Intervention: Low vs. moderate glycemic index

Intervention Type: OTHER

Interventions

Dietary Intervention: Low vs. moderate glycemic index

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• written consent to participate,
• male and female,
• a current medical clearance to practice sports,
• training experience: at least 3 years,
• minimum of 4 workout sessions a week lasting at least 1.5-2 hours/day,
• age: 17 - 37 years.

Exclusion Criteria

• current injury,
• any health-related contraindication,
• declared general feeling of being unwell,
• unwilling to follow the study protocol,
• smoking, illicit drug use, alcohol consumption greater than 1-2 drinks/week, dietary supplements use less than 3 weeks before the study,
• females- being pregnant or planning to become pregnant during the study.

• Minimum Eligible Age: 17 Years
• Maximum Eligible Age: 37 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Poznan University of Life Sciences

OTHER

Sponsor Role: lead

Responsible Party

Krzysztof Durkalec-Michalski, PhD

Assistant Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Jan Jeszka, Professor

Role: STUDY_CHAIR

Department of Hygiene and Human Nutrition, Poznan University of Life Sciences, Poznan, Poland

Locations

Poznan University of Life Sciences, ul.Wojska Polskiego 31

Poznan, Wielkopolska, Poland

Countries

Poland

Other Identifiers

ULS00001

Identifier Type: -

Identifier Source: org_study_id