Maple Syrup Carbohydrate Dose-Response on 20-km Cycling Time-Trial Performance (MAPLE-DR)

Université de Montréal

Status: Not yet enrolling

Conditions: Carbohydrate Intolerance; Endurance Cycling Performance; Exercise; Sport Nutrition

Treatments: Other: Hedonic Ratings; Procedure: D₂O Fluid Absorption; Procedure: Substrate Oxidation; Diagnostic Test: Perceptual Responses; Diagnostic Test: Gastrointestinal Symptoms; Other: Blinding Integrity; Procedure: Blood Metabolites; Behavioral: Time Trial Performance; Dietary Supplement: placebo beverage; Dietary Supplement: Maple Syrup Beverages; Diagnostic Test: Neuromuscular Fatigue; Other: Pre-Trial Meals

Study type: Interventional

Funder types: Other; Industry

Identifiers

NCT07389837

ICM 2026-3568

Details and patient eligibility

About

The goal of this clinical trial is to learn whether maple syrup can be used as a natural carbohydrate source to help trained male cyclists perform better during long-duration cycling. The study also aims to learn how different amounts of maple syrup affect energy use in the body, stomach comfort, and feelings of effort and fatigue.

The main questions the study aims to answer are:

• Does consuming more carbohydrate from maple syrup help participants finish a 20-kilometer cycling time trial faster?
• How do different amounts of maple syrup change how the body uses carbohydrates and fats during long exercise?
• Are higher amounts of maple syrup easy for participants to tolerate without stomach problems?

Researchers will compare four drinks:

1. A placebo drink (a look-alike drink with no calories),
2. A drink that provides 60 grams of carbohydrate per hour,
3. A drink that provides 90 grams per hour, and
4. A drink that provides 120 grams per hour.

They will compare these drinks to see whether higher carbohydrate amounts lead to better cycling performance and how each dose affects comfort and metabolism.

Participants will:

• Attend a screening visit that includes a health check and a glucose tolerance test.
• Complete a fitness test to measure their aerobic capacity and practice the cycling tests used in the study.
• Take part in four separate exercise sessions in random order. Each session includes:
• Drinking one of the four study beverages during 2 hours of steady cycling,
• Completing two short, all-out 6-second sprints during the ride,
• Completing a 20-kilometer cycling time trial as fast as possible,
• Reporting stomach symptoms and perceptions of effort,
• Providing breath, blood, urine, and sweat samples so researchers can measure how their body uses fuel.

All drinks will look, taste, and smell similar so participants cannot tell which one they are receiving. Meals before each session will be provided to keep conditions the same across visits.

This study may help athletes and active people choose natural carbohydrate sources that support both performance and comfort during long endurance exercise. The findings may also guide future research on the use of maple syrup as a sports nutrition option.

Enrollment: 32 estimated patients

Sex: Male

Ages: 18 to 45 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Age: 18-45 years.
• Relative VO2max: >55 mL·min-¹·kg-¹ for level 3; >65 mL·min-¹·kg-¹ for level 4.
• Peak Power Output (PPO): >4.6 W·kg-¹ (absolute PPO >320 W).
• Training History: >5 hours/week of cycling-specific training; >1 year of consistent endurance training.
• No history of metabolic disorders, gastrointestinal issues, or contraindications to exercise testing.

Exclusion criteria

• Current or past metabolic disorders (diabetes, metabolic syndrome)
• Cardiovascular disease or abnormal ECG at rest
• Gastrointestinal disorders (IBS, Crohn's, celiac disease)
• Food allergies or intolerances (particularly maple, fructose)
• Current use of medications affecting metabolism
• Smoking or nicotine use
• Alcohol consumption >14 units/week
• Recent illness or injury (<4 weeks)
• Participation in other clinical trials (<3 months)
• Unable to maintain consistent training during study period

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Double Blind

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32 participants in 4 patient groups, including a placebo group

Maple syrup providing 60g of CHO per hour

Experimental group

Description:

The protocol begins with a 10-minute warm-up at 100 W, followed by a 120-minute constant-load cycling phase at 65% PPO, during which the 60 g/h maple syrup solution is consumed every 15 minutes as the main intervention. Neuromuscular fatigue is assessed four times (baseline, 60 min, 120 min into the constant-load, and post-TT) using two 6-second all-out seated sprints (from a 100 W rolling start); these two sprints are separated by a 1-minute active recovery at 100 W, after which the 65% PPO cycling is immediately resumed for the in-exercise timepoints. The constant-load phase is concluded by a 5-minute complete recovery, immediately followed by the 20-km self-paced Time Trial (completed without fluids), with the final set of sprints performed immediately after the TT to assess residual fatigue.

Treatment:

Diagnostic Test: Gastrointestinal Symptoms

Other: Pre-Trial Meals

Dietary Supplement: placebo beverage

Behavioral: Time Trial Performance

Diagnostic Test: Neuromuscular Fatigue

Procedure: Blood Metabolites

Dietary Supplement: Maple Syrup Beverages

Other: Blinding Integrity

Procedure: Substrate Oxidation

Other: Hedonic Ratings

Diagnostic Test: Perceptual Responses

Procedure: D₂O Fluid Absorption

Maple syrup providing 90g of CHO per hour

Experimental group

Description:

The protocol begins with a 10-minute warm-up at 100 W, followed by a 120-minute constant-load cycling phase at 65% PPO, during which the 90 g/h maple syrup solution is consumed every 15 minutes as the main intervention. Neuromuscular fatigue is assessed four times (baseline, 60 min, 120 min into the constant-load, and post-TT) using two 6-second all-out seated sprints (from a 100 W rolling start); these two sprints are separated by a 1-minute active recovery at 100 W, after which the 65% PPO cycling is immediately resumed for the in-exercise timepoints. The constant-load phase is concluded by a 5-minute complete recovery, immediately followed by the 20-km self-paced Time Trial (completed without fluids), with the final set of sprints performed immediately after the TT to assess residual fatigue.

Treatment:

Diagnostic Test: Gastrointestinal Symptoms

Other: Pre-Trial Meals

Dietary Supplement: placebo beverage

Behavioral: Time Trial Performance

Diagnostic Test: Neuromuscular Fatigue

Procedure: Blood Metabolites

Dietary Supplement: Maple Syrup Beverages

Other: Blinding Integrity

Procedure: Substrate Oxidation

Other: Hedonic Ratings

Diagnostic Test: Perceptual Responses

Procedure: D₂O Fluid Absorption

Maple syrup providing 120g of CHO per hour

Experimental group

Description:

The protocol begins with a 10-minute warm-up at 100 W, followed by a 120-minute constant-load cycling phase at 65% PPO, during which the 120 g/h maple syrup solution is consumed every 15 minutes as the main intervention. Neuromuscular fatigue is assessed four times (baseline, 60 min, 120 min into the constant-load, and post-TT) using two 6-second all-out seated sprints (from a 100 W rolling start); these two sprints are separated by a 1-minute active recovery at 100 W, after which the 65% PPO cycling is immediately resumed for the in-exercise timepoints. The constant-load phase is concluded by a 5-minute complete recovery, immediately followed by the 20-km self-paced Time Trial (completed without fluids), with the final set of sprints performed immediately after the TT to assess residual fatigue.

Treatment:

Diagnostic Test: Gastrointestinal Symptoms

Other: Pre-Trial Meals

Dietary Supplement: placebo beverage

Behavioral: Time Trial Performance

Diagnostic Test: Neuromuscular Fatigue

Procedure: Blood Metabolites

Dietary Supplement: Maple Syrup Beverages

Other: Blinding Integrity

Procedure: Substrate Oxidation

Other: Hedonic Ratings

Diagnostic Test: Perceptual Responses

Procedure: D₂O Fluid Absorption

Placebo

Placebo Comparator group

Description:

The protocol begins with a 10-minute warm-up at 100 W, followed by a 120-minute constant-load cycling phase at 65% PPO, during which the placebo solution (sweetened water, with sotolon for maple taste) is consumed every 15 minutes as the main intervention. Neuromuscular fatigue is assessed four times (baseline, 60 min, 120 min into the constant-load, and post-TT) using two 6-second all-out seated sprints (from a 100 W rolling start); these two sprints are separated by a 1-minute active recovery at 100 W, after which the 65% PPO cycling is immediately resumed for the in-exercise timepoints. The constant-load phase is concluded by a 5-minute complete recovery, immediately followed by the 20-km self-paced Time Trial (completed without fluids), with the final set of sprints performed immediately after the TT to assess residual fatigue.

Treatment:

Diagnostic Test: Gastrointestinal Symptoms

Other: Pre-Trial Meals

Dietary Supplement: placebo beverage

Behavioral: Time Trial Performance

Diagnostic Test: Neuromuscular Fatigue

Procedure: Blood Metabolites

Dietary Supplement: Maple Syrup Beverages

Other: Blinding Integrity

Procedure: Substrate Oxidation

Other: Hedonic Ratings

Diagnostic Test: Perceptual Responses

Procedure: D₂O Fluid Absorption