Maple Syrup Carbohydrate Dose-Response on 20-km Cycling Time-Trial Performance

NCT07389837 | Not Yet Recruiting

• 1 other identifier: ICM 2026-3568
• Study Type: interventional
• Target: 32
• Locations: 1 country
• Sites: 1

Brief Summary

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

Conditions

Exercise; Endurance Cycling Performance; Carbohydrate Intolerance; Sport Nutrition

Keywords

13C-glucose; cycling exercise; endurance performance; carbohydrate; substrate oxidation

Outcome Measures

Primary Outcomes (1)

• Assess the dose-response effect of maple syrup carbohydrate ingestion (0, 60, 90, 120 g·h-¹) on 20-km cycling time-trial performance in trained male cyclists.

  20-km time trial completion time (minutes), measured at the end of each experimental visit.

  Immediately after completion of the 20-km time trial during each experimental visit

Secondary Outcomes (6)

• Substrate oxidation rates during exercise

  At rest, immediately before exercise, and every 30 minutes during 120 minutes of constant-load cycling

• Plasma metabolite concentrations

  Measured before beverage ingestion, immediately pre-exercise, every 30 minutes during the 120-minute constant-load cycling, and immediately post-exercise (before the time trial).

• Ratings of perceived effort during exercise

  Assessed 3 minutes after exercise begins; every 30 minutes during the constant-load cycling (30, 60, 90, 120 min); and at approximately 126, 127, 130, 136, and 145 minutes (corresponding to 0.5, 5, 10, 15, and 20 km during the time trial)

• Assess gastrointestinal tolerance and symptoms across maple syrup doses and placebo.

  Measured pre-exercise; every 30 minutes during the 120-minute constant-load cycling (30, 60, 90, 120 min); and immediately after the time trial.

• Peak power output during maximal sprints

  Baseline, 60 minutes, 120 minutes, and immediately after time trial

Other Outcomes (6)

• Hedonic ratings for beverage sweetness, flavor, and liking

  Immediately after time trial completion

• Explore correlations between substrate oxidation rates and TT performance.

  Evaluated using oxidation values measured during cycling (at rest, pre-exercise, and at 30, 60, 90, 120 min) and TT performance measured at approximately 150-155 minutes (immediately after time trial completion)

• Examine inter-individual variability in dose-response patterns for performance outcomes.

  Calculated from repeated TT measurements collected at each of 4 experimental visits over approximately 4-6 weeks

Study Arms (4)

Maple syrup providing 60g of CHO per hour

EXPERIMENTAL

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.

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

Maple syrup providing 90g of CHO per hour

EXPERIMENTAL

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.

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

Maple syrup providing 120g of CHO per hour

EXPERIMENTAL

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.

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

Placebo

PLACEBO COMPARATOR

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.

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

Interventions

Maple Syrup Beverages DIETARY_SUPPLEMENT

Pure maple syrup is diluted in water and mixed with electrolytes (sodium, potassium, magnesium) to resemble a sports drink. Participants receive one of three carbohydrate doses (60, 90, or 120 g per hour). Drinks are ingested every 15 minutes during 120 minutes of cycling, for a total of \~750 mL per hour. All doses have the same volume, temperature, electrolyte content, and schedule.

Maple syrup providing 120g of CHO per hour; Maple syrup providing 60g of CHO per hour; Maple syrup providing 90g of CHO per hour; Placebo

placebo beverage DIETARY_SUPPLEMENT

Participants receive a calorie-free electrolyte drink designed to mimic maple syrup. Sotolon (maple aroma) and stevia are added in small amounts to reproduce sweetness, flavor, and smell without providing energy. The drink is administered in identical volumes and timing to the maple syrup beverages (\~750 mL per hour, every 15 minutes).

Maple syrup providing 120g of CHO per hour; Maple syrup providing 60g of CHO per hour; Maple syrup providing 90g of CHO per hour; Placebo

Pre-Trial Meals OTHER

To control nutrition before each trial, participants are provided with a standardized dinner the night before and a standardized breakfast 2-3 hours before testing. Meals contain the same calories and macronutrient distribution across all sessions. Participants must also replicate their training during the previous 48 hours.

Maple syrup providing 120g of CHO per hour; Maple syrup providing 60g of CHO per hour; Maple syrup providing 90g of CHO per hour; Placebo

Blood Metabolites PROCEDURE

Blood samples collected every 30 minutes measure glucose, insulin, lactate, and fatty acids. Samples are stored for later analysis of hormonal and metabolic responses.

Maple syrup providing 120g of CHO per hour; Maple syrup providing 60g of CHO per hour; Maple syrup providing 90g of CHO per hour; Placebo

Blinding Integrity OTHER

Bang's Blinding Index is calculated from participant guesses of drink identity to confirm whether blinding was successful.

Maple syrup providing 120g of CHO per hour; Maple syrup providing 60g of CHO per hour; Maple syrup providing 90g of CHO per hour; Placebo

D₂O Fluid Absorption PROCEDURE

At 30 minutes of cycling, participants ingest a small, safe dose of deuterium oxide (7-8 mL) to measure fluid absorption and gastric emptying. Additional blood samples are collected at +32, +35, and +40 minutes to capture early absorption. Urine is collected to measure deuterium enrichment and validate absorption kinetics.

Maple syrup providing 120g of CHO per hour; Maple syrup providing 60g of CHO per hour; Maple syrup providing 90g of CHO per hour; Placebo

Time Trial Performance BEHAVIORAL

After 120 minutes of steady cycling, participants complete a 20-km self-paced time trial. Only distance is displayed. The primary outcome is completion time; mean power is analyzed as supportive information.

Maple syrup providing 120g of CHO per hour; Maple syrup providing 60g of CHO per hour; Maple syrup providing 90g of CHO per hour; Placebo

Substrate Oxidation PROCEDURE

Energy metabolism is measured using indirect calorimetry and ¹³C-sucrose breath enrichment. Samples are collected at rest and every 30 minutes during exercise to quantify carbohydrate and fat use, distinguishing ingested vs. stored carbohydrate oxidation. Urine and sweat correct protein oxidation.

Maple syrup providing 120g of CHO per hour; Maple syrup providing 60g of CHO per hour; Maple syrup providing 90g of CHO per hour; Placebo

Gastrointestinal Symptoms DIAGNOSTIC_TEST

Participants rate stomach symptoms (0-10 scale) before exercise, every 30 minutes during cycling, and after the time trial. Scores quantify total, upper, and lower GI discomfort.

Maple syrup providing 120g of CHO per hour; Maple syrup providing 60g of CHO per hour; Maple syrup providing 90g of CHO per hour; Placebo

Perceptual Responses DIAGNOSTIC_TEST

Effort and muscle pain are assessed using the Borg CR100 scale during exercise and throughout the time trial at preset intervals.

Maple syrup providing 120g of CHO per hour; Maple syrup providing 60g of CHO per hour; Maple syrup providing 90g of CHO per hour; Placebo

Neuromuscular Fatigue DIAGNOSTIC_TEST

Participants perform two 6-second maximal sprints at baseline, 60 and 120 minutes of cycling, and after the time trial. Peak power, cadence, and torque assess fatigue progression and recovery.

Maple syrup providing 120g of CHO per hour; Maple syrup providing 60g of CHO per hour; Maple syrup providing 90g of CHO per hour; Placebo

Hedonic Ratings OTHER

Immediately post-exercise, a 0-100 mm scale evaluates sweetness, flavor intensity, and overall liking to assess palatability of each drink.

Maple syrup providing 120g of CHO per hour; Maple syrup providing 60g of CHO per hour; Maple syrup providing 90g of CHO per hour; Placebo

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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.

You may not qualify if:

• 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

Sponsors & Collaborators

• Université de Montréal: lead
• Mitacs: collaborator
• Natural Sciences and Engineering Research Council, Canada: collaborator
• Montreal Heart Institute: collaborator
• Quebec Maple Syrup Producers: collaborator
• Quebec Cycling Federation: collaborator

Study Sites (1)

Centre EPIC

Montreal, Quebec, H1T 1N6, Canada

Location

Related Publications (8)

• Cermak NM, van Loon LJ. The use of carbohydrates during exercise as an ergogenic aid. Sports Med. 2013 Nov;43(11):1139-55. doi: 10.1007/s40279-013-0079-0.

  PMID: 23846824 BACKGROUND

• Stellingwerff T, Cox GR. Systematic review: Carbohydrate supplementation on exercise performance or capacity of varying durations. Appl Physiol Nutr Metab. 2014 Sep;39(9):998-1011. doi: 10.1139/apnm-2014-0027. Epub 2014 Mar 25.

  PMID: 24951297 BACKGROUND

• Jeukendrup AE. Carbohydrate and exercise performance: the role of multiple transportable carbohydrates. Curr Opin Clin Nutr Metab Care. 2010 Jul;13(4):452-7. doi: 10.1097/MCO.0b013e328339de9f.

  PMID: 20574242 BACKGROUND

• Vandenbogaerde TJ, Hopkins WG. Effects of acute carbohydrate supplementation on endurance performance: a meta-analysis. Sports Med. 2011 Sep 1;41(9):773-92. doi: 10.2165/11590520-000000000-00000.

  PMID: 21846165 BACKGROUND

• Smith JW, Zachwieja JJ, Peronnet F, Passe DH, Massicotte D, Lavoie C, Pascoe DD. Fuel selection and cycling endurance performance with ingestion of [13C]glucose: evidence for a carbohydrate dose response. J Appl Physiol (1985). 2010 Jun;108(6):1520-9. doi: 10.1152/japplphysiol.91394.2008. Epub 2010 Mar 18.

  PMID: 20299609 BACKGROUND

• Hearris MA, Pugh JN, Langan-Evans C, Mann SJ, Burke L, Stellingwerff T, Gonzalez JT, Morton JP. 13C-glucose-fructose labeling reveals comparable exogenous CHO oxidation during exercise when consuming 120 g/h in fluid, gel, jelly chew, or coingestion. J Appl Physiol (1985). 2022 Jun 1;132(6):1394-1406. doi: 10.1152/japplphysiol.00091.2022. Epub 2022 Apr 21.

  PMID: 35446596 BACKGROUND

• Lavoie L, Tremblay J. Ingestion of maple-based and other carbohydrate sports drinks: effect on sensory perceptions during prolonged exercise. J Int Soc Sports Nutr. 2020 Dec 9;17(1):63. doi: 10.1186/s12970-020-00384-3.

  PMID: 33298104 BACKGROUND

• De Pauw K, Roelands B, Cheung SS, de Geus B, Rietjens G, Meeusen R. Guidelines to classify subject groups in sport-science research. Int J Sports Physiol Perform. 2013 Mar;8(2):111-22. doi: 10.1123/ijspp.8.2.111.

  PMID: 23428482 BACKGROUND

MeSH Terms

Conditions

Motor Activity; Glucose-Galactose Malabsorption

Condition Hierarchy (Ancestors)

Behavior

Study Officials

• Jonathan Tremblay, PhD

  Université de Montréal

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Philippe Parent, BSc

CONTACT

+1-438-393-9720; philippe.parent.1@umontreal.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Full Professor

Model Details: This is a randomized, double-blind, placebo-controlled, crossover trial designed to maximize statistical power. Each participant will serve as their own control, completing four experimental conditions in computer-randomized order.

Study Record Dates

• First Submitted: January 2, 2026
• First Posted: February 5, 2026
• Study Start: February 1, 2026
• Primary Completion (Estimated): December 30, 2026
• Study Completion (Estimated): June 1, 2027
• Last Updated: February 5, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ANALYTIC CODE
• Time Frame: 12 months after primary results publication and for at least 5 years
• Access Criteria: Qualified researchers at accredited institutions may request access to de-identified IPD and supporting materials (protocol, SAP, and analytic code if available). Requests must include a study synopsis, analysis plan, variables needed, and documentation of IRB/ethics approval. The PI/sponsor data access committee will review for scientific merit, feasibility, and privacy protection. Approved users must sign a Data Use Agreement prohibiting re-identification, onward sharing, and commercial use; publications must acknowledge the original study. Access will be time-limited via a secure repository with role-based permissions, encryption, and audit logs; only aggregate results may be publicly released. Linkage to external datasets requires explicit approval.

Locations

CA (1)