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NCT Number: NCT04097171

The Effect of Diet Composition on Performance, Expenditure, Blood Lipids, and Appetite Hormones 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.

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Key information

Conditions

Endurance Cycling Performance

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Texas Christian University

Fort Worth, Texas, 76129, United States

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Diet

Other

Participants will consume each diet for 14 days in a crossover design.

Primary outcomes

  1. Endurance Cycling Performance

    Time frame: 180 min after the meal begins

    Time to completion in a 30-kilometer simulated time trial

Secondary outcomes

  1. Respiratory Exchange Ratio

    Time frame: 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

  2. Muscle Fuel Rating

    Time frame: Change from baseline at 180 min and 240 min after the meal begins

    Ultrasound echogenicity of Rectus Femoris

  3. Oxygen consumption (VO2)

    Time frame: At 192 min, 204 min, 216 min, 228 min and 240 min after the meal begins

    Indirect calorimetry during exercise

  4. Rating of Perceived Exertion (RPE)

    Time frame: At 192 min, 204 min, 216 min, 228 min and 240 min after the meal begins

    6-20 Borg's scale during exercise

  5. Thermic Effect of Food (postprandial energy expenditure)

    Time frame: 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

  6. Subjective appetite ratings

    Time frame: 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]

  7. Appetite hormones including ghrelin, leptin, insulin, and Peptide-YY

    Time frame: Change from baseline at 30 min, 60 min, 120 min, 180 min and 240 min

    Fasted, postprandial & post exercise blood concentration of appetite hormones

  8. Blood glucose

    Time frame: 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

  9. Blood pressure

    Time frame: Change from baseline at 180 min after the meal begins

    Fasted, postprandial & post exercise

  10. Cognitive function

    Time frame: At 180 min and 240 min after the meal begins

    Stroop test

  11. Mood state questionnaire

    Time frame: 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"

  12. Resting Metabolic Rate

    Time frame: At baseline before meal begins

    Indirect calorimetry in fasted state

  13. Blood lipids including (triglycerides, total cholesterol, low density lipoprotein, and high-density lipoprotein)

    Time frame: 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

Sponsors and collaborators

Lead sponsor

Texas Christian University

Other

Registry information

Official study title

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

Acronym: DCAP

Important dates

Study start
2019
Primary completion
2020
Study completion
2020
First posted
Sep 20, 2019
Registry last updated
Oct 5, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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