The Effect of Diet Composition on Performance, Expenditure, Blood Lipids, and Appetite Hormones in Highly Trained Cyclists

Not Applicable

Completed

• Conditions: Endurance Cycling Performance
• Interventions: Other: Diet

• Registration Number: NCT04097171
• Lead Sponsor: Texas Christian University

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 Timeline

• Study First Submitted: 2019-09-17
• Study First Submitted QC: 2019-09-18
• Study First Posted: 2019-09-20
• Study Start: 2019-11-11
• Primary Completion: 2020-03-30
• Study Completion: 2020-03-30
• Status Verified: 2021-10
• Last Update Submitted: 2021-10-04
• Last Update Posted: 2021-10-05

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 34

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Ketogenic Diet	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.
High Carbohydrate Diet	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.

Primary Outcome Measures

Name	Time	Method
Endurance Cycling Performance	180 min after the meal begins	Time to completion in a 30-kilometer simulated time trial

Secondary Outcome Measures

Name	Time	Method
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
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
Oxygen consumption (VO2)	At 192 min, 204 min, 216 min, 228 min and 240 min after the meal begins	Indirect calorimetry during exercise
Muscle Fuel Rating	Change from baseline at 180 min and 240 min after the meal begins	Ultrasound echogenicity of Rectus Femoris
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
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 \[0-100 mm\]
Blood pressure	Change from baseline at 180 min after the meal begins	Fasted, postprandial \& post exercise
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
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
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
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"

Trial Locations

Locations (1)

Texas Christian University; 🇺🇸 Fort Worth, Texas, United States