Endurance Cycling Performance
Conditions
Brief summary
This study employs a crossover design to evaluate the effect of two different diets (high carbohydrate vs. ketogenic) and corresponding test meals on endurance exercise performance, energy expenditure including resting metabolic rate and thermic effect of food, postprandial responses of blood lipids, glucose and appetite hormones, and cognitive function and mood states.
Detailed description
Traditionally, a high carbohydrate diet is recommended for elite endurance athletes and sub-elite, highly trained recreational athletes competing in endurance events. However, recently the ketogenic diet (extremely low carbohydrate content) has become popular in these populations. The effect on endurance exercise performance, energy expenditure, postprandial blood profiles, and cognitive function and mood states requires further investigation. In this study, highly trained recreational cyclists and triathletes will adhere to each diet (high-carbohydrate and ketogenic) for 14 days in a crossover design. Experimental trials at baseline and after each diet will evaluate endurance cycling performance (time trial), resting energy expenditure, the thermic effect of food of test meals corresponding in composition to each diet, postprandial responses of blood lipids, glucose and appetite hormones, and cognitive function and mood states.
Interventions
OTHERDiet
Participants will consume each diet for 14 days in a crossover design.
Sponsors
Texas Christian University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
* \>100-150km of cycling per week * VO2max \> 80th percentile for sex and age (adjusted for cycle ergometry) * apparently healthy
Exclusion criteria
* weight loss supplements/medications/diet * extreme dietary patterns (e.g. extremely high or low carbohydrate) * nicotine use * heavy alcohol use (\>7 drinks/week female; \>14 drinks/week male) * food allergies * diabetes * heart disease * stroke * liver/kidney/thyroid disease * anemia * eating disorders * uncontrolled hypertension * pulmonary/orthopedic/musculoskeletal problems that prevent exercise * surgery that affects swallowing and digestion * claustrophobia
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Endurance Cycling Performance | 180 min after the meal begins | Time to completion in a 30-kilometer simulated time trial |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Muscle Fuel Rating | Change from baseline at 180 min and 240 min after the meal begins | Ultrasound echogenicity of Rectus Femoris |
| Oxygen consumption (VO2) | At 192 min, 204 min, 216 min, 228 min and 240 min after the meal begins | Indirect calorimetry during exercise |
| Rating of Perceived Exertion (RPE) | At 192 min, 204 min, 216 min, 228 min and 240 min after the meal begins | 6-20 Borg's scale during exercise |
| Thermic Effect of Food (postprandial energy expenditure) | Change from baseline at 30 min, 60 min, 90 min, 120 min, 150 min, 180 min after the meal begins | Fasted vs. postprandial indirect calorimetry |
| Subjective appetite ratings | Change from baseline at 60 min, 120 min, 180 min after the meal begins | Visual Analog Scale (Scale 1: Perception of Hunger \[0-100 mm\]; Scale 2: Perception of Fullness \[0-100 mm\]; Scale 3: Desire to Eat \[0-100 mm\] |
| Appetite hormones including ghrelin, leptin, insulin, and Peptide-YY | Change from baseline at 30 min, 60 min, 120 min, 180 min and 240 min | Fasted, postprandial & post exercise blood concentration of appetite hormones |
| Respiratory Exchange Ratio | Change from baseline at 30 min, 60 min, 90 min, 120 min, 150 min, 180 min, 192 min, 204 min, 216 min, 228 min and 240 min after the meal begins | Indirect calorimetry fasted, postprandial, and during exercise |
| Blood pressure | Change from baseline at 180 min after the meal begins | Fasted, postprandial & post exercise |
| Cognitive function | At 180 min and 240 min after the meal begins | Stroop test |
| Mood state questionnaire | At 180 min and 240 min after the meal begins | Abbreviated Profile of Mood States; 40-item scale; Likert scale from 0 = not at all to 4 = extremely |
| Resting Metabolic Rate | At baseline before meal begins | Indirect calorimetry in fasted state |
| Blood lipids including (triglycerides, total cholesterol, low density lipoprotein, and high-density lipoprotein) | Change from baseline at 30 min, 60 min, 120 min, 180 min, 192 min, 204 min, 216 min, 228 min and 240 min after the meal begins | Fasted and postprandial in mg/dL |
| Blood glucose | Change from baseline at 180 min and 240 min after the meal begins; on day 7 of each diet | Fasted, postprandial & post exercise blood concentration of glucose |
Countries
United States
Outcome results
None listed