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

The Effect of Diet Composition on Performance, Energy Expenditure, Blood Lipids and Lipoproteins, and Cognitive Function and Mood States in Highly Trained Cyclists

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.

Study Overview

• Status: Completed
• Conditions: Endurance Cycling Performance
• Intervention / Treatment: Other: Diet

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 Type: Interventional
• Enrollment (Actual): 34
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Texas
    • Fort Worth, Texas, United States, 76129
      • Texas Christian University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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 Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 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.	Other: Diet; Participants will consume each diet for 14 days in a crossover design.
Experimental: 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.	Other: Diet; Participants will consume each diet for 14 days in a crossover design.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Endurance Cycling Performance	Time to completion in a 30-kilometer simulated time trial	180 min after the meal begins

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Respiratory Exchange Ratio	Indirect calorimetry fasted, postprandial, and during exercise	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
Muscle Fuel Rating	Ultrasound echogenicity of Rectus Femoris	Change from baseline at 180 min and 240 min after the meal begins
Oxygen consumption (VO2)	Indirect calorimetry during exercise	At 192 min, 204 min, 216 min, 228 min and 240 min after the meal begins
Rating of Perceived Exertion (RPE)	6-20 Borg's scale during exercise	At 192 min, 204 min, 216 min, 228 min and 240 min after the meal begins
Thermic Effect of Food (postprandial energy expenditure)	Fasted vs. postprandial indirect calorimetry	Change from baseline at 30 min, 60 min, 90 min, 120 min, 150 min, 180 min after the meal begins
Subjective appetite ratings	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]	Change from baseline at 60 min, 120 min, 180 min after the meal begins
Appetite hormones including ghrelin, leptin, insulin, and Peptide-YY	Fasted, postprandial & post exercise blood concentration of appetite hormones	Change from baseline at 30 min, 60 min, 120 min, 180 min and 240 min
Blood glucose	Fasted, postprandial & post exercise blood concentration of glucose	Change from baseline at 180 min and 240 min after the meal begins; on day 7 of each diet
Blood pressure	Fasted, postprandial & post exercise	Change from baseline at 180 min after the meal begins
Cognitive function	Stroop test	At 180 min and 240 min after the meal begins
Mood state questionnaire	Abbreviated Profile of Mood States; 40-item scale; Likert scale from 0 = "not at all" to 4 = "extremely"	At 180 min and 240 min after the meal begins
Resting Metabolic Rate	Indirect calorimetry in fasted state	At baseline before meal begins
Blood lipids including (triglycerides, total cholesterol, low density lipoprotein, and high-density lipoprotein)	Fasted and postprandial in mg/dL	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

Collaborators and Investigators

• Sponsor: Texas Christian University

Study record dates

Study Major Dates

• Study Start (Actual): November 11, 2019
• Primary Completion (Actual): March 30, 2020
• Study Completion (Actual): March 30, 2020

Study Registration Dates

• First Submitted: September 17, 2019
• First Submitted That Met QC Criteria: September 18, 2019
• First Posted (Actual): September 20, 2019

Study Record Updates

• Last Update Posted (Actual): October 5, 2021
• Last Update Submitted That Met QC Criteria: October 4, 2021
• Last Verified: October 1, 2021

More Information

Terms related to this study

• Other Study ID Numbers: CT2019MS3

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Yes
• IPD Plan Description: De-identified study data of all outcome variables will be shared on an Open Science Framework project page (osf.io) along with the study protocol, statistical analysis plan, and analytic code
• IPD Sharing Time Frame: Will become available at the latest June 2021 and be available indefinitely
• IPD Sharing Access Criteria: Openly available
• IPD Sharing Supporting Information Type: Study Protocol; Statistical Analysis Plan (SAP); Analytic Code

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No