The Effect of Diet Composition on Performance, Energy Expenditure, Blood Lipids and Lipoproteins, and Cognitive Function and Mood States in Highly Trained Cyclists
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- Texas Christian University
- Enrollment
- 34
- Locations
- 1
- Primary Endpoint
- Endurance Cycling Performance
Study Overview
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.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Basic Science
- Masking
- None
Eligibility Criteria
- Ages
- 18 Years to 65 Years (Adult, Older Adult)
- Sex
- All
- Accepts 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
- •heart disease
- •liver/kidney/thyroid disease
- •eating disorders
- •uncontrolled hypertension
- •pulmonary/orthopedic/musculoskeletal problems that prevent exercise
- •surgery that affects swallowing and digestion
- •claustrophobia
Arms & Interventions
Ketogenic Diet
Participants will consume a low carbohydrate diet (<5-10% of total energy intake). Protein intake will be standardized at 15% of total energy intake.
Intervention: Diet (Other)
High Carbohydrate Diet
Participants will consume a high carbohydrate diet (65-75% of total energy intake). Protein intake will be standardized at 15% of total energy intake.
Intervention: Diet (Other)
Outcomes
Primary Outcomes
Endurance Cycling Performance
Time Frame: 180 min after the meal begins
Time to completion in a 30-kilometer simulated time trial
Secondary Outcomes
- 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)
- Resting Metabolic Rate(At baseline before meal begins)
- 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)
- Oxygen consumption (VO2)(At 192 min, 204 min, 216 min, 228 min and 240 min after the meal begins)
- Muscle Fuel Rating(Change from baseline at 180 min and 240 min after the meal begins)
- Rating of Perceived Exertion (RPE)(At 192 min, 204 min, 216 min, 228 min and 240 min after the meal begins)
- Subjective appetite ratings(Change from baseline at 60 min, 120 min, 180 min after the meal begins)
- Blood pressure(Change from baseline at 180 min after the meal begins)
- 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)
- Appetite hormones including ghrelin, leptin, insulin, and Peptide-YY(Change from baseline at 30 min, 60 min, 120 min, 180 min and 240 min)
- Blood glucose(Change from baseline at 180 min and 240 min after the meal begins; on day 7 of each diet)
- Cognitive function(At 180 min and 240 min after the meal begins)
- Mood state questionnaire(At 180 min and 240 min after the meal begins)
Investigators
Meena Shah
Interim Chair, Professor and Director, Graduate Program
Texas Christian University